U.S. patent application number 12/835587 was filed with the patent office on 2011-01-13 for methods and compositions for preparing consumables with optical shifting properties.
Invention is credited to Hans O. Ribi.
Application Number | 20110008498 12/835587 |
Document ID | / |
Family ID | 27084021 |
Filed Date | 2011-01-13 |
United States Patent
Application |
20110008498 |
Kind Code |
A1 |
Ribi; Hans O. |
January 13, 2011 |
Methods and Compositions for Preparing Consumables with Optical
Shifting Properties
Abstract
Ingestible compositions comprising a chromic change agent
together with methods of making and using them are provided. The
chromic change agent alternatively may be associated with the
ingestible, such as a packaging material for the ingestible. In
response to a triggering event, physical or chemical, the chromic
change agent changes color to provide information as to the history
of the ingestible, either prior or contemporaneous with use.
Depending on the use, the color change agent may be reversible or
irreversible. Various solid or liquid ingestible compositions are
provided for determining ingestible temperature, storage
temperature, user temperature, light exposure, pH change, hydration
or solvation change, mechanical stress, and the like, particularly
in comestibles. Of particular interest are polydiacetylene polymers
that may be formulated to provide compositions having numerous
different color transition triggering mechanisms. The invention is
also related to other chromic change agents that may be
incorporated into ingestibles.
Inventors: |
Ribi; Hans O.;
(Hillsborough, CA) |
Correspondence
Address: |
BOZICEVIC, FIELD & FRANCIS LLP
1900 UNIVERSITY AVENUE, SUITE 200
EAST PALO ALTO
CA
94303
US
|
Family ID: |
27084021 |
Appl. No.: |
12/835587 |
Filed: |
July 13, 2010 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
11523723 |
Sep 18, 2006 |
7776371 |
|
|
12835587 |
|
|
|
|
10302368 |
Nov 22, 2002 |
|
|
|
11523723 |
|
|
|
|
09892018 |
Jun 25, 2001 |
|
|
|
10302368 |
|
|
|
|
09602001 |
Jun 23, 2000 |
6607744 |
|
|
09892018 |
|
|
|
|
Current U.S.
Class: |
426/87 ;
426/231 |
Current CPC
Class: |
A23L 5/47 20160801; G01N
31/22 20130101; A23L 5/42 20160801; G01N 31/229 20130101; C07C
233/20 20130101 |
Class at
Publication: |
426/87 ;
426/231 |
International
Class: |
G01N 33/02 20060101
G01N033/02 |
Claims
1-7. (canceled)
8. A method for detecting whether an ingestible has been exposed to
an absolute temperature level, said method comprising: associating
with said ingestible a diacetylenic compound that undergoes an
irreversible color change when subjected to a change in
temperature, wherein a color change associated with said ingestible
is indicative that said ingestible has been exposed to said
absolute temperature level.
9. The method according to claim 8, wherein said diacetylenic
compound is attached to a container or packaging material for
ingestibles.
10. The method according to claim 8, wherein said color change
indicates said ingestible has been spoiled.
11. The method according to claim 8, wherein said color change
indicates said ingestible is cooked.
12-20. (canceled)
21. A method for manufacturing an ingestible comprising a
diacetylenic compound, said method comprising applying said
diacetylenic compound in a composition of up to 75% weight % of a
diacetylenic compound.
22. The method according to claim 21, whereby said composition is
up to about 60% weight % of a diacetylenic compound.
23. The method according to claim 21, whereby said composition of
up to about 20% weight % of a diacetylenic compound.
24. The method according to claim 21, wherein said diacetylenic
compound is a lipid mono- or dicarboxylic non-oxo carbonyl monomer,
or derivative thereof.
25-28. (canceled)
29. An ingestible comprising a chromic change agent that undergoes
a color change one or more times in response to at least one
physical or chemical triggering mechanism.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation in part of U.S. Ser. No.
09/892,018 filed Jun. 25, 2001 which is a continuation in part of
U.S. Ser. No. 09/602,001 filed Jun. 23, 2000, which disclosures are
hereby incorporated by reference.
INTRODUCTION
[0002] 1. Technical Field
[0003] The field of this invention is methods and compositions for
preparing an edible consumable or ingestible comprising one or more
chromic change agent that is safe for human or animal consumption
that interactively modulates a color transition in the edible
consumable or ingestible.
[0004] 2. Background
[0005] Foods, beverages, medications and a variety of edible
products with intrinsic color change properties can find a
multitude of uses for manufacturers and consumers alike. They can
be developed and marketed for entertainment purposes, such as
graphics on the surface of food that change color, giving rise to a
visual effect that is both pleasing and interesting for children. A
variety of new food categories can be produced to contain the
chromic material. Food producers are in need of new means to
differentiate brands, extend product lines, advertise and promote,
and create new product lines. Generally, food developers are
limited to new flavors, colors, presentations, packaging, and
combinations for product differentiation. Entirely new categories
of foods, beverages, and medications can be created by introducing
a new intrinsic property during processing.
[0006] Color changes may release or expose hidden messages which
can be used for promotional or marketing purposes. Color changes
can visually signal the consumer when the food is "done" to a
satisfactory extent and safe to eat, or that the food is still in
the process of being cooked. Color changes can be used to
communicate optically with a cooking instrument telling the cooking
instrument the level of doneness through a bar code change.
[0007] Color change foods can indicate to consumers or institutions
that the food offered is sterile due to its color at purchase.
Subsequent changes in color could indicate that the food has become
stale or spoiled. Safe food storage temperatures can be indicated
by the food or beverage directly where a color change indicates
that the food was held at an inappropriate temperature for a period
of time. The color change can be used to signal the timely release
of a certain nutrient or flavor into the food. The chromic change
can also be used to communicate the nature of food to be consumed.
For example, chromic change agents can tell the consumer how "hot"
a hot sauce really is, the fat content of certain foods, the level
of carbonation in soft drinks, or the level of a biological or
chemical in a food, such as caffeine or allergens.
[0008] Certain spices and other foods should be irradiated with
high-energy sources to ensure that potential microbial
contamination has been eliminated, thereby protecting the consumer.
Foods containing a chromic agent that changes color upon
irradiation can communicate to the consumer or the food processor
that proper irradiation has taken place.
Relevant References
[0009] Colored food products on the market today involve the use of
commercialized dyes combined with a capsule of waxes or other
opaque matrices that mask the underlying dye. The dye molecules
become visually exposed upon dissolving or melting of the
encapsulating material. An example of releasing a dye into hot
water involves Quaker Oat's Deep Blue Hot Oatmeal. An example of
dissolving a coated dye into cold milk involves a version Nabisco's
Oreo Cookie that releases a blue dye into milk when the cookie is
dipped into the milk. An example using melting waxes to reveal an
underlying color involves Kellogg's PopTarts where a white wax is
coated over a colored sprinkle. When the pastry is heated the wax
melts to reveal the color. An example of beverage additive is Kraft
Food's Kool-Aid Magic Twists incorporating an entrapped dye that
becomes revealed as the coating on the food color is dissolved. An
example of a color change when a food product is eaten is
FritoLay's Cheeto's Cheese Puffs, which release a dye into one's
mouth when the product is wetted and chewed. An example of a
chewing gum which turns one's mouth blue is Blue Mouth Chewing Gum
from Creative Products Manufacturing. In each case a color is
revealed by releasing or exposing a hidden dye and not an intrinsic
chromic change that results from a molecular change in the chromic
change agent itself.
[0010] References of interest include U.S. Pat. Nos. 4,859,538;
5,144,112; 5,156,810; 5,189,281; 5,273,360; 5,415,999; 5,685,641;
5,788,375; 5,918,981; and 6,046,455.
SUMMARY OF THE INVENTION
[0011] Environmentally responsive components are intrinsically
associated with ingestibles, such as foods, beverages and
medicaments, to be consumed as part of the ingestible, while
providing knowledge of an informative or entertaining character.
Specifically, physiologically acceptable chromic materials, e.g.
polymerized polyacetylenes, are associated with the ingestible so
as to be consumed by the user. The chromic material changes color
in response to various environmental clues, such as temperature,
pH, radiation, and physical stress, among others.
DESCRIPTION OF THE SPECIFIC EMBODIMENTS
[0012] Ingestibles are provided comprising a chromic material that
changes color in response to environmental cues.
[0013] A variety of color change triggering processes can be used
to cause the color change of chromic change agents depending on the
type of chemistry involved, such as temperature, pH changes,
changes in ionic strength, mechanical changes such as stress or
pressure during mixing or contortion, chemical changes such as the
addition of a second component, exposure to light for a
photochromic effect, biochemical reactions such as binding pair
interaction (e.g., an antibody-antigen interaction, a
receptor-ligand interaction), solvent environment changes,
hydration or dehydration, solvent changes, and enzymatic changes
where enzymes in the food can induce a change. The color-indicating
material can be processed directly into the ingestible, coated on
the surface, released in a timely manner, or be made to be exposed
through a discrete color change triggering process.
[0014] By ingestibles is intended compositions that are taken
orally, even though they may not be digested. Therefore,
ingestibles include foods, medicaments, toothpaste, mouth washes,
gargles, swabs, and the like, where the food is introduced into the
mouth and may then be rejected or may reside in the mouth for a
limited period of time. Since foods are the primary application of
the subject invention, foods are discussed as illustrative of
ingestibles generally. The chromic materials are physiologically
acceptable, particularly polymerized polyacetylenes, which can be
incorporated with the ingestible during or after processing. Only a
small amount of the chromic material need be incorporated, where
the chromic material may be suffused through the ingestible,
partially penetrate the ingestible or primarily be an adherent
coating on the ingestible. The ingestible is porous or liquid, so
that the chromic composition, by itself or in conjunction with an
edible carrier, interpenetrates the ingestible, where the
penetration may be throughout the ingestible, a limited depth into
the ingestible, or into the surface to provide an adherent
surface.
[0015] Polydiacetylenes as a class of ingestible chromic agents
offer several advantages since they exhibit a broad range of
beneficial characteristics. They have a large extinction
coefficient showing a high color contrast, so that proportionally
less chromic change material may be required to achieve an optical
effect than materials such as entrapped dyes. Polydiacetylenes are
organic and can be modified to create a wide range of permutations
applicable to different chromic triggering mechanisms, ingestible
applications, and processing methods. They can be structurally
modified to have more than one intrinsic color change (e.g.
blue-magenta-red or blue red-yellow). They can be modified to be
compatible with the different food matrices (e.g., fats, aqueous,
starch, protein, inorganic salts, sugars or the like). They can be
made structurally inert such that they are odorless and tasteless,
thus not affecting the foods to which they are added. The polymer
form is a high molecular weight structure thereby, reducing its
potential for adsorption during the digestion process.
Polydiacetylenes are compatible with a variety of compositions used
in the food industry for coatings and processing, making them
amenable to existing processing methods without complete processing
line redesign (e.g., solid food forms or liquid food forms). They
can be made into stable forms making them good candidates for
tolerating the stresses of production, shipping and storage.
[0016] Polydiacetylenic and other chromic change materials that
undergo an intrinsic color change respond directly to a triggering
event rather than simply releasing a color. A direct response
chromic change has the significant advantage that the chromic agent
itself can be engineered and designed to meet a broad and varied
interest in the food, pharmaceutical and other relevant industries.
In the case of polydiacetylenic materials, the chromic agent can be
chemically enhanced with different substituents and functional
groups for various applications while maintaining the intrinsic
color change characteristics. The unique conformational change
mechanism that polydiacetylenes undergo during a color-changing
triggering event provides a unique means to match the material with
food-based chemistries, food processing methods, and printing and
application processes.
[0017] Since polydiacetylenic materials can be modified to change
color to a variety of different optical triggering mechanisms, they
have the additional advantage that they may serve as indicators or
reporters for a variety of different monitoring processes of
interest to the food and pharmaceutical industries and consumers.
Examples of such monitoring processes include cooking temperatures,
presence of toxic chemical or microbial contaminants, heavy metal,
the presence of carcinogens, allergens that can cause an immediate
deadly reaction if the food is consumed, food content (e.g.
specific substances in food which can induce a color change event
if present), DNA or RNA, various gene products or genetically
engineered substances, food oxidation state, freshness,
temperatures that the food may have been raised to during shipping
and handling, whether certain foods have been irradiated according
to specific guidelines, and the like.
[0018] Diacetylenic and polydiacetylenic compounds may be produced
in a multitude of forms or substituents for compatibility and
functionality with foods, beverages and medications. The
diacetylenic group may be modified with lipid-like groups for solid
phase or liquid phase compatibility, carbohydrates, sugars, polar
and apolar groups, functional groups such as amines, carboxylic
acids, alcoholic groups, esters, amides, charge complexes,
aliphatic groups, ethers, polyethers, amino acids, proteins,
nucleic acids, mesogenic side chains, sulfhydryl groups, block
co-polymers and other groups which may be used to create
specifically desired characteristics. Compositions may be prepared
having up to about 20 weight % of the polydiacetylenic polymer for
coating, which compositions further comprise carbohydrates, lipids
or other physiologically acceptable composition.
[0019] The diacetylenic compounds or chromic agents present,
whether monomers or polymers, in the composition added to the
ingestible will generally be present in at least 1 weight %, more
usually at least about 5 weight %, and may be 75 weight % or more,
usually being not more than about 60 weight %.
[0020] Diacetylenic monomer chemistries: Classes of photochromic,
thermochromic, hydrochromic, lipochromic, and physiochromic
polymers can be made from a variety of organic diacetylenic
monomers including short chain molecules with no side chains or
substituents, short chain molecules containing one or more
functional groups and aliphatic monomers that vary in length from
10 carbon units to 50 or more carbon units with or without various
functional side chains or substituents. Molecules can be
hydrophobic or hydrophilic depending on the desired application.
They can be neutral or charged in order to create a desired
intermolecular or intramolecular effect. The molecule can be
non-polar, mono-polar, or multi-polar. Diacetylenic monomers can be
symmetric or asymmetric. For food grade applications, the monomer
and subsequent polymer molecules can contain food compatible groups
including sugars, lipid chains, carbohydrate moieties, amino acids,
peptides, proteins, complex proteins, effector groups, esters,
alcoholic groups, amides, carboxamides, dextrans, heterocyclic
substituents, acids, lipids, detachable nutrient groups, such as
vitamins and nutraceuticals, catalytic groups such as enzymes,
chelating groups, nucleotides, food colors, emulsifier groups, or
the like.
[0021] Side chains and substituents may be chemically modified for
use with a variety of different foods. The hydrophobic or
hydrophilic nature of the chemical compound can be adjusted to
create compositions more or less compatible with fatty foods,
carbohydrate-based foods, meats, dry foods, cereals, baked goods or
the like.
[0022] The diacetylenic monomer will be a lipid mono- or
dicarboxylic non-oxo carbonyl monomer or derivative thereof, so
that acid, esters, or amides may be employed, a mono- or diol,
ether or ester thereof, where the acid may be organic or inorganic,
e.g. phosphate, an amino or derivative thereof, where the
derivative may be an organic substituent such as an acyl group, an
aliphatic group, an aromatic group, a heterocyclic group, etc. The
substituents at the termini will have from 0 to 30, more usually 0
to 20 atoms, which will usually be carbon, oxygen, nitrogen, sulfur
and phosphorous. The acid portion of the molecule (or underivatized
portion) will generally range from 5-30, more usually 12-30, carbon
atoms and the diacetylene groups which will be in conjugation, may
be situated symmetrically or asymmetrically in the molecule. Thus,
the flanking alkylene groups may be the same or different in a
molecule, where the temperature transition of the polymer will
depend upon the chain length of the monomer, whether the
diacetylene groups are symmetrical or asymmetrical, and the degree
of difference between the length of the flanking regions, whether
one uses a single monomer to form a homopolymer or two or more
monomers, usually not more than four monomers, to form a
co-polymer, and whether the chains are substituted or
unsubstituted, as well as the nature and degree of substitution.
Particularly, halogen substituents, e.g. fluorine, chlorine and
bromine, may be present to enhance the upper temperature limits
possible with the subject compositions, ranging from a single
substituent to persubstituted. The temperature range which is
attainable using the various diacetylene monomers will range from
about 25-300.degree. C., usually not exceeding 200.degree. C., more
usually from about 25-200.degree. C. For the purposes of this
invention, the range of interest will be from about 30-200.degree.
C., more usually from about 35-200.degree. C., and particularly
from about 35-150.degree. C.
[0023] For the most part, the diacetylene monomers will have the
following formula:
R(CH.sub.2).sub.n(C.ident.C).sub.2(CH.sub.2).sub.mY (1)
wherein:
[0024] Y is COX.sup.1, amino (including substituted amino, e.g.
alkyl substituted amino of from about 1-6 carbon atoms), oxy having
from 0 to 6 carbon atoms, thio of from 0 to 6 carbon atoms, cyano,
halo, etc.;
[0025] m and n are at least 1 and total 8-25, preferably n is at
least 2, more preferably both m and n are at least 2;
[0026] R is H or Y; and
[0027] X and X' may be the same or different, usually the same, may
be any of the groups indicated above, generally being H, OH, OT,
where T is of from 1-8, usually 1-6 carbon atoms having from
0-(n-2) substituents, wherein n is the number of carbon atoms and
the substituent may be oxy, amino, halo, thiol, etc, usually
aliphatic, e.g. hydroxyalkyl, and aminoalkyl; or NT.sup.1, T.sup.2,
wherein T.sup.1 and T.sup.2 are the same or different, usually the
same and will have from 1-8, usually 1-6 carbon atoms, the total
number of carbon atoms of T.sup.1 and T.sup.2 usually not being
greater than about 6 and each having from 0-(n-2) substituents as
described above, particularly oxy, one of T.sup.1 and T.sup.2 may
be unsubstituted or substituted amino (hydrazino), where the
substituents will come within the definition of T.sup.1,
polyalkyleneoxy, wherein alkylene is of from 2 to 3 carbon atoms
and may have from 2 to 50 units; or two Y's may be taken together
to form a divalent linking group of from about 2 to 2,000 daltons,
which will usually be 2 T's taken together (T+s include T and
T.sup.1). Monomers can be used individually and in pure form. The
position of the acetylenic groups may be symmetrical or
asymmetrical in the molecule.
[0028] Of particular interest are monomers, such as
10,12-tricosadiynoic acid (C23) or 10,12-pentacosadiynoic acid
(C25), which can be used independently during processing and
production to achieve a lower sensitivity to ultraviolet
irradiation (254 nm) or either compound may be added in a
percentage to the other to sensitize the mixture to make the
mixture far more sensitive to ultraviolet irradiation. 0.01-50% by
weight of C25 can be added to C23 to make a mixture that
polymerizes 50% or more quickly and achieves a much darker blue
appearance after polymerization. More usually, 0.1 to 30% C25 is
added to C23.
[0029] Typically, 1 to 20% C25 is added to C23. Formulation
variations along with ultraviolet irradiation times can be used to
create different thermochromic temperature settings. Combinations
of formulations can be used to achieve a variety of visual effects
upon temperature triggering including patterns such as text,
characters, images, symbols, trademarks, brand identity marks,
messages, icons, logos, artistic designs or decorative designs.
Patterns may appear to change non-uniformly to create visual
imagery such as the appearance of movement in a stationary
picture.
[0030] The general structure of a diacetylenic monomer that is
polymerized to become a polydiacetylenic chromic change agent
consists of a diacetylenic unit with appending side chains on each
end of the diacetylenic unit
A(CH.sub.2)n--.ident.--.ident.--(CH.sub.2)mB (2)
[0031] The corresponding polydiacetylenic unit capable of
undergoing a chromic change is a continuous ene-yne structure with
A(CH.sub.2)n and (CH.sub.2)mB each as side chains attached to an
individual ene-yne unit:
##STR00001##
where Z represents the number of repeating units along the
polydiacetylene backbone. Z can range in number from 2 to greater
than 100,000. Usually Z will vary from 5 to 10,000. Typically Z
will be between 10 and 1,000 units.
[0032] The number of methylene units n and m may be increased or
decreased depending on the application of interest. Increasing the
number of methylene units can have dramatically different effects
on the resulting chromic triggering mechanisms. Altering the
substituents A and B can have the effect of sensitizing, tuning or
optimizing a particular chromic triggering mechanism in the chromic
change agent. The composite structural features of an ingestible
chromic change agent can be related to both the chromic change
mechanism as well as the degree of responsiveness or
non-responsiveness of the agent to a triggering event. Illustrative
examples of chromic agent color change mechanisms and enabling
structural features are summarized below but are not intended to
limit the scope of possible mechanisms or structural
permutations.
[0033] Photochromic agent color changes: The primary enabling
feature for a diacetylenic material to be photopolymerizable such
that exposure to ultraviolet light (254 nm) results in the
formation of a color formation is the ordered crystal packing state
of the monomeric diacetylenic unit. A, B n, and m must be balanced
such that diacetylene crystals are aligned and can be
topochemically polymerized. Typically A and B should be of a
molecular size and structure to promote and not inhibit crystal
packing or sterically restrict the diacetylenic units from packing
close enough to each other in a crystal lattice as to restrict
ene-yne bond formation to occur between units. A and B can be
similar or dissimilar in structure. A and n can be paired to
comprise an alkyl chain and give the molecule favorable
hydrophobic-hydrophobic interactions for inducing good crystal
packing. B and m can comprise an identical alkyl chain to A and n
to give the photochrome a wax-like characteristic. In contrast, m
can be between 1 to 20 units while B can be a simple hydrophilic
head group such as an alcohol or amine. B can be more complex such
as a carboxylic acid or amide linkage. Amine, amide, and carboxylic
acid groups (B) paired with alkyl chains (A/n) make excellent
ultraviolet photochromic candidates.
[0034] Short chain lipid-like compounds, where n=3, A is a methyl
group, m=3 and B=COOH (see formula (3), above) form photochromic
compounds that turn red at room temperature when exposed to
ultraviolet (254 nm) light between 0.degree. C. and 30.degree. C.
Long chain lipid-like compounds, where in combination n is between
4 and 20, A is a methyl group, m is between 2 and 20 and B=COOH
form photochromic compounds that turn blue when exposed to
ultraviolet light (254 nm) from as low as 0.degree. C. to as high
as 100.degree. C.
[0035] Symmetric compounds where the diacetylenic group is in a
fatty acid form and is dimerized by bridging each fatty acid group
through an amide linkage with ethylene diamine or 1,4-diaminobutane
make excellent candidates for photochromic agents due to their
facile crystallization and polymerization characteristics.
[0036] Mechanochromic agent enabling features: Mechanochromic
agents can be similar in structure to photochromic agents. A good
crystalline matrix of the monomeric diacetylenic moiety is first
formed followed by ultraviolet polymerization (254 nm). For
mechanochromic triggering, it is desirable to start with a highly
ordered blue polydiacetylenic polymer. Mechanical perturbation
subsequently changes the blue form of the polymer to the red form.
Other chromic changes such as conversion of the blue or red polymer
form to a yellow form are also possible to achieve through intense
and continued perturbation. Since only a mechanical stress such as
rubbing, sheering, compressing, or similar physical means is
required to cause a chromic change in the chromic agent and not a
specific chemical reaction, the mechanochromic molecular structure
has few limitations.
[0037] The structure can be a simple alkyl chain, a fatty acid, an
ester, an amide, a carbonate group, a thiol, an ether group, a
polyethylene group, a sugar, a carbohydrate, an amino acid or a
variety of other groups that do not adversely affect a mechanically
induced triggering event. The ease of inducing a mechanochromic
change is dictated by the selected structure. Rigid crystal
structures with a high degree of structural integrity of the
mechanochromic polymer require a higher level of mechanical
perturbation to induce a chromic change as compared with loosely
packed crystal structures with weaker intermolecular interactions.
For example, 5,7-hexadecadiynoic acid (16 carbons in length)
requires little mechanical pressure to induce a chromic change in
the polymer whereas 10,12-pentacosadiynoic acid (25 carbons in
length) requires several times more mechanical pressure to induce a
chromic change. Typically, the shorter the hydrocarbon chains (n
and m less than 5) embedding the diacetylenic polymer the less
mechanical stress required to change its color. Weakly interactive
head groups or side chains such as esters groups (B) can be used to
reduce the mechanical stress required to induce a chromic change
whereas strongly hydrogen bonding head groups such as multiple
amides increase the amount of stress required to induce a
change.
[0038] The degree of polymerization (Z) can play an important role
in dictating the mechanical forces required to induce a chromic
change. Short repeating units, caused from mild polymerization
(e.g. where Z is 3-10 units), can result in less required force
needed to induce a change. Longer repeating units, caused by
extensive ultraviolet polymerization, (e.g. where Z is from 50 to
over 1,000), can result in requiring significantly greater forces
to induce a chromic change.
[0039] Thermochromic agent enabling features: A primary feature
dictating a thermally induced chromic change is the melting
transition of side chains appended to the polydiacetylenic
structure. Similar to the mechanochromic example, shorter, more
weakly interactive side chains typically require lower heat levels
to induce a chromic change. Longer, more strongly interactive side
chains typically require higher heat levels. In the case of
thermochromically induced changes, it is desirable to utilize side
chain substituents most affected by temperature changes. Lipids,
waxes and other hydrocarbons can be used. In combination with side
chain substituents, more strongly or weakly functional groups may
be used to adjust the thermochromic transition.
[0040] Ester groups, for example, exhibit weak intermolecular
interactions and are useful in lowering the thermochromic
transition temperature, whereas amides exhibit strong hydrogen
bonding interactions between adjacent repeating units and find use
to raise the thermochromic transition temperature and facilitate a
reversible thermochromic reaction. Sugar molecules exhibit a high
degree of intermolecular hydrogen bonding and can be used to
synthesize high temperature thermochromically reversible
ingestibles (B) whereas polyethylene oxide substituents can be used
as substituents (B) to synthesize lower temperature irreversible
compounds. Permutations of the hydrocarbon chain lengths (n and m)
appending the diacetylenic unit can be used to fine-tune the
desired temperature change setting.
[0041] The degree of polymerization (Z) also plays an important
role in dictating the temperature at which the chromic change will
occur. Short repeating units, caused from mild ultraviolet
polymerization (e.g., where Z is 3-10 units), can result in lower
thermochromic transition temperatures. Longer repeating units,
caused by extensive ultraviolet polymerization, (e.g. where Z is
from 50 to over 1,000), can result in a significantly higher
thermochromic transition temperature.
[0042] The compounds used to react with the carboxyl groups may be
selected in relation to the ingestible to be modified. Thus, the
groups may be chosen to make the polyacetylenes more compatible
with the ingestible, using polar compounds to enhance compatibility
with polar ingestibles, non-polar compounds to make the
polyacetylenes more compatible with lipid compounds, solubilizing
groups which provide for solubility or dispersibility, and the
like. Certain photochromic materials can undergo a second color
transition upon high heat (greater than 200.degree. F.) from a red
color to a yellow color and then reverse colors upon cooling back
to room temperature. Among such materials are the dual chain
glutamate diacetylene containing lipids. Mono-amide glutamate
lipids and tri-amide glutamate lipids can be used alone or in
combination to achieve similar effects at lower temperatures. For
example, the molecule can be modified to have strong hydrogen
bonding characteristics that cause strong intermolecular
interactions between monomers along a polymer chain and exert a
strong ordering characteristic along the chain. Strong
intramolecular or interpolymer chain hydrogen bonding helps to
stiffen and order the polymer backbone. Heading or perturbing the
backbone cause a stochastic conformational change along the polymer
that results in a color change from a highly ordered blue structure
to a red disordered structure. Cooling or reversing conditions
allows the intermolecular or intra-polymer chain hydrogen bonding
interactions to dominate and re-order the polymer chain to an
ordered blue structure. Among such materials are single chain
lipids containing one or more amides for promoting intermolecular
hydrogen bonding. For example, acetylated ethylene
diamide-10,12-triconsdiyneoic amide contains two internal amide
linkages along a single chain compound. Alternatively, dual chain
lipids containing a mono-, di- or triamide glutamate head group can
be used. In addition carboxylic acid lipids where the diacetylenic
back bone is in close proximity with the head group (1-4 carbon
atoms removed) have a large influence over the polymer structure
and can exhibit reversibility (e.g. 4,6-heptadecadiynoic acid) at
moderate temperatures (68.degree. F. to 130.degree. F.). Reversible
thermochromic materials can be made using glutamic acid with two
chains of 10,12-tricosadiynoic acid to form a dual chain glutamate
lipid. Dual chain glutamate lipids exhibit a high degree of
thermochromic reversibility due the interlocking nature of the
microcrystalline structure and/or their hydrogen bonding
characteristics. Generally there will be from 1 to 10, more usually
from about 1 to 8 hydrogen forming groups in a repeating unit of
the polymer, such as amide, hydroxy, keto, amino, etc.
[0043] A chemical/structural balance between carbon chain length,
position of the diacetylenic group along the carbon chain, hydrogen
bonding due to the amide linkage, and head group structure can be
achieved in the chromic change agent to give it characteristics of
reversibility, food compatibility, processing ease, color change
mechanism, stability, and other factors beneficial to use as an
ingestible.
[0044] Diacetylenic forms of the chromic agent can be made into a
high temperature reversible material by creating a dual amide
symmetric compound where two long chain fatty acids
(10,12-pentacosadiynoic acid) are bridged by an amide linkage by
1,4-butane diamine. The resulting material forms a plastic/wax-like
polymerizable material which remains dark blue until it is heated
above 150.degree. C. Halogenating the even longer chain fatty acids
along their methylene units can further raise the triggering
transition temperature to greater than 300.degree. C.
[0045] Depending on the type of application, it may be desirable to
have an irreversible thermochromic or physiochromic event or a
reversible event. Hot liquids containing a reversible thermochromic
material, for example, can be made to turn red at a high
temperature and back to blue at some intermediate or room
temperature. Upon reheating, the liquid would turn red again.
[0046] Cereals containing a low temperature reversible chromic
material can be red at room temperature and change to blue upon
addition of cold milk. An irreversible thermochromic material can
be used to show a pattern change in a solid pastry indicating that
the pastry was indeed heated to a certain temperature to reveal a
message or picture which stays the same even after cooling. Single
chain monomers such as 10,12-tricosadiynoic acid can be polymerized
to form an irreversible thermochromic property.
[0047] For lower temperature applications such as visualizing a
color change when a food is brought to room temperature or above,
it is desirable to have a thermochromic compound which responds
immediately to an ambient room temperature. 10,12-tricosadiynoic
acid or 10,12-pentacosadiynoic acid can be converted to the methyl
ester form to create materials which change color from a deep dark
blue to irreversible bright red, at about 80.degree. F. These can
be useful for indicating that certain foods, which should be stored
at less than room temperature, have been raised or heated to higher
than room temperature. For example, in some cases such as certain
medications, dairy products or foods, it is desirable to store them
at room temperature or below and keep them from being raised even
slightly above room temperature. In these cases, it may be
desirable to incorporate a thermochromic material, which tells
consumers that the product has at one time been held at an
undesirably high temperature and should no longer be consumed. It
may be advantageous to have the thermochromic material in direct
contact with the consumable medication or food and not with
packaging, so that no false indications are made, and precluding
expensive items from being disposed of inappropriately. Shorter
hydrocarbon chains attached to the diacetylenic backbone can also
be incorporated to reduce the energy or impact required to trigger
a chromic transition. A balance between the hydrogen bonding, Van
der Waals interactions, charge-charge interactions,
hydrophobic-hydrophilic interactions, can be achieved to produce
the desired type and situation for color changing ingestibles.
[0048] Hydrogen bonding functional groups attached to monomers can
be used to influence the chromic properties of corresponding
polymers. Tightly hydrogen-bonding groups can increase the energy
required for the chromic material to change color. Reducing the
hydrogen bonding capabilities of the chromic material can be used
to reduce the energy or degree of change in environment to cause a
color change. Hydrogen-bonding groups include polar atoms, such as
oxygen and nitrogen, to which the hydrogen is bound. Hydrogen
bonding can be structured between individual chromic molecules or
between chromic molecules and surrounding carrier materials with
which they are in association.
[0049] Of particular interest are thermochromically revisable
monomers such as N-ethanol-hexadeca-5,7-diyneamide and
N-propylamineeicosa-5,7-diyneamide. These compounds when
polymerized with ultraviolet light (254 nm), become deeply magenta
colored at room temperature. When the polymers are raised above
room temperature they become red/orange and when they are chilled
below room temperature, they become a deep purple/blue color. The
thermochromic transition of N-ethanol-hexadeca-5,7-diyneamide is
approximately 5.degree. C. lower than
N-propylamine-eicosa-5,7-diyneamide. The lower temperature
triggering transition was achieved by using an ethanolamine head
group rather than a propylamine head group and using a shorter 16
carbon chain rather than a longer 20 carbon chain.
N-ethanol-hexadeca-5,7-diyneamide finds application to color
changing cereals where at room temperature the cereal will appear
magenta/red and turn blue when cold milk is added to the cereal.
N-propylamine-eicosa-5,7-diyneamide finds application to coatings
on cookies where at room temperature the cookie appears a dark
magenta. When the cookie is touched, raising its temperature above
room temperature, the cookie appears red. When the cookie is dipped
in cold milk, the cookie appears dark blue/purple.
[0050] High-temperature reversible chromic agents find multiple
uses both indicators that foods have been raised above a safe
cooking level (e.g., one color will appear above 160.degree. F.)
and then subsequently as indicators that foods have been cooled to
a level that makes them safe to eat without burning tissue in the
mouth (e.g., the original color will reappear near 110.degree.
F.).
[0051] Chemical changes such as these provide for wide range of
latitude to modify the chromic agent for a particular triggering
range and product application. Food or other ingestible products
often have discrete requirements such as shipping, storage, level
of contaminants, acceptable moisture content or the like.
[0052] Irreversible color changes in polydiacetylenes can be
introduced by eliminating or reducing the intermolecular or
intra-polymer chain hydrogen bonding characteristics. For example,
the polydiacetylenic molecule can be a pure hydrocarbon structure
without substituents, an ester or have other relatively
non-interactive groups. Additionally, the triggering temperature
can be dramatically reduced and made irreversible by using short
carbon chains such as 5,7-dodecadiynoic acid amidated with
2-(2-aminoethoxy)ethanol. The material is an oil at room
temperature and will only polymerize at -10.degree. C., where a
blue polymer can be formed by ultraviolet irradiation (254 nm).
Raising the temperature above -10.degree. C. causes the material to
irreversibly turn red/orange. Materials such as these can find use
in low temperature food applications.
[0053] Irreversible color changes are important to ingestibles
containing them when it is desired to observe a color change at a
certain temperature level and it is desired to maintain "memory" of
the temperature level achieved at a given time or location. It is
convenient to use irreversible thermochromic color change in
polydiacetylenes during a temperature increase, converting the blue
form of the color to a red form. For example, a thermochromic
message can be revealed on a toaster pastry and the message is
permanent until the pastry is ingested.
[0054] Extended triggering conditions can be achieved in
polydiacetylenic compounds by creating unique structures including
attachment of constituent moieties such as sugars, amine acids or
peptides, DNA or RNA, polyether groups, binding pairs, or organic
groups which can dominate the material's characteristics. Maximum
temperature triggering ranges attainable can be extended to
-30.degree. C. or below to greater than 350.degree. C., usually not
exceeding 300.degree. C. and not below 25.degree. C., and more
usually from between -20.degree. C. to 250.degree. C. For the
purpose of this invention the range of interest will be from
-15.degree. C. to 225.degree. C., and particularly from -10.degree.
C. to 200.degree. C.
[0055] Likewise, the substituents can be added to provide for other
means to disrupt or order the polymer structure and thereby cause a
reversible or irreversible color change in the polymer backbone, as
described below.
[0056] Hydrochromic/solvatochromic agent enabling features: An
important feature dictating the hydrochromic/solvatochromic nature
of the chromic agent is the ease of degree to which the material
can be effectively hydrated of solvated by a surrounding medium.
The mechanism for inducing a hydration or solvation change can be
accomplished either by affecting individual substituent side chains
or by hydrating/solvating complete layers adjacent to each other in
the crystalline lattice. As with other chromic change mechanisms,
the ease or difficulty of inducing a chromic change can be dictated
by the integrity of crystal packing and the strength of
intermolecular side chain interactions.
[0057] Good hydrating side chain groups A and B include alcohols;
polyethers such as polyethylene glycol terminated with an OH group,
surfactant groups or the like. Solvation-induced chromic changes,
where polar aprotic solvents such as acetone are used as the
triggering agent, are effective when the side chain substituents
are easily solvated with acetone. For example, n and m can be low
in number (e.g. 1 to 3 units) and the head group can be a like kind
substituent such as a ketone or ester. Water-induced chromic
changes are facilitated when both the intermolecular interactions
between side chains and the intercrystalline interactions between
layers of the crystal lattice are affected by water. It can be
desirable to use symmetric compounds where A=B and non and both A
and B are groups that are easily hydrated as well as groups which
permit intercalation of water between layers in a crystal.
[0058] Mono- or multiple alcoholic groups can be introduced to
promote interaction with hydrating or solvating solutions. Solvent
or hydrochromic color changes are particularly attractive when
combining dry ingestibles with wet or moist ingestibles. For
example, adding milk to cold cereal, dipping cookies or crackers in
milk, adding crackers to soup, pouring liquid syrups on breads or
pancakes, adding salad dressings to salads, or the like, can be the
trigger for a color change.
[0059] In addition, hydrochromic/solvatochromic effects can be used
in unique ways to propagate a color change along a surface. As
hydration occurs along an absorbent layer and the moisture
migrates, a blue form of the polymer sensitive to solvation or
hydration will turn the disordered red of the polymer to the
ordered blue form. Messages or graphics can be visualized
sequentially to create time-resolved graphical changes.
[0060] Ethylene glycol or polyethylene glycol groups can be
attached to the monomeric material to alter the solubility with
different food types or help emulsify the monomeric chromic agent.
Ethylene glycol linkers can range from a single ethylene oxide unit
to 50 units. More typically, ethylene glycol linkers range from 2
to 20 units and most conveniently from 3 to 6 units. The number of
units can be changed depending on the desired level of hydrophobic
or hydrophilic nature for the resulting molecule.
[0061] Standard hydrochromic/solvatochromic indicating groups can
be attached in positions A and/or B to endow the base chromic
change agent with moisture-indicating properties.
[0062] pH sensitive and ionochromic change agent enabling features:
It is desirable to attach pH or ion sensitive substituent groups to
the base molecular structure such that a change in solution pH or
ionic strength in the surrounding medium can induce a chromic
change in the polydiacetylenic backbone. As with other chromic
change mechanisms, the ease or difficulty of inducing a chromic
change can be dictated by the integrity of crystal packing and the
strength of intermolecular side chain interactions. For example,
groups that respond to ionic strength such as a carboxylic acid can
be used at positions A and/or B. It is desirable to use shorter
side chain lengths (e.g., n and m less than 4) in order to
facilitate a higher degree of molecular mobility. A dicarboxylic
acid where A and B are both COOH and n and m are both 1 to 3 are of
interest as ionochromic constituents since both ends of the
molecule are affected during a triggering phase.
[0063] Groups susceptible to protonation or deprotonation or
acid-base reactions are of particular interest. For example, A
and/or B can be a primary amine, secondary amine or the like.
Changing the surrounding medium from a neutral pH to an acidic pH
can be used to cause a chromic change in the medium. When A and/or
B is an organic acid such as a mono or dicarboxylic form, treating
the medium with a basic solution may induce a chromic change in the
agent.
[0064] pH sensitive groups, e.g. bases and acids such as a
hydrazide or a free amine group, can be attached to the head group
of a lipid or hydrocarbon moiety to invoke a pH-triggering response
from the blue form of the polydiacetylenic polymer to a red form of
the polydiacetylenic polymer. Ethylene glycol or polyethylene
glycol groups can be attached to the monomeric material to alter
the solubility with different food types or help emulsify the
monomeric chromic agent.
[0065] Ethylene glycol linkers can range from a single ethylene
oxide unit to 50 units. More typically, ethylene glycol linkers
range from 2 to 20 units and most conveniently from 3 to 6 units.
The number of units can be changed depending on the desired level
of hydrophobic or hydrophilic nature for the resulting
molecule.
[0066] Standard pH-indicating groups can be attached in positions A
and/or B. Indicators specific to a particular pH unit are of
interest since they may find use as ingestibles to monitor saliva
pH. Ionophore-sensitive groups can be attached in position A and/or
B to endow the base chromic change agent with ion-selective
properties.
[0067] Chemochromic and biochromic agent enabling features: It is
desirable to attach chemically or biochemically sensitive and/or
selective groups to A and/or B to give the chromic agent
specificity to certain chemical constituents in an ingestible
matrix. As with other chromic change mechanisms, the ease or
difficulty of inducing a chromic change can be dictated by the
integrity of crystal packing and the strength of intermolecular
side chain interactions.
[0068] Examples of chemically selective groups can include caged
compounds, chelating compounds, crown ether groups, peptides, DNA
or RNA fragments, transition state analogs, binding pair members,
or the like. Groups A and/or B can be more or less selective
depending on the ingestible application. The chromic agent can be
made more or less sensitive to chemical or biochemical triggering
by increasing or decreasing n and m, respectively; shorter chain
lengths typically require of lower concentrations of the chemical
or biochemical to induce a chromic change, whereas longer chain
lengths generally require higher concentrations of the chemical or
biochemical required to induce a chromic change.
[0069] Formulations and compositions: Monomeric or polymeric
chromic change materials can be combined with a carrier material to
form a composition which makes it possible for it to be applied to
and/or adhered to foods. Carrier materials can range from a simple
aqueous solution to complex mixtures containing different
emulsifiers, flavors, or foodstuff. Constituents such as oils,
lipids, waxes, sugars, salts, lectins, agglutinins, protein
matrices, carbohydrate matrices or the like can be combined alone
or together with an unpolymerized agent or polymerized agent to
give the agent the properties necessary for transfer to, adherence
with, or stability on a food type.
[0070] Carrier materials suitable for printing can include aqueous
solutions or pastes, which are applied and dried more slowly.
Alternatively, the solution can contain an ethanol base, which can
be dried more quickly. The carrier for printing can contain any
food compatible composition.
[0071] Carrier materials suitable for extrusion can contain
thickening substances to give it the consistency for rapid
extrusion and pattern formation on the food surface of interest.
Starches, methylcellulose, but pastes, dextrins, polydextrins,
protein pastes, sugars, dried gelatins, rice papers, doughs,
frostings, sugar-based papers, edible inks, edible waxes,
ingestible polymer substrates, caramelized sugars, or the like can
be used for a support surface to which the chromic agent can be
applied. Thickened carriers provide for the ability to form three
dimensional structures such as overlaying lines or patterns, that
can enhance the contrast for the thermochromic or physiochromic
color transition. Carriers suitable for lamination can include
substances that provide for stable layers to be applied to the food
of interest.
[0072] Binding agents can be used to integrate more or less of the
chromic material with a particular food type. In most cases, it is
desirable to bind the chromic material tightly to the food so that
the material stays visibly in contact with the particular part of
the food portion it is initially on and that the material does not
slough off into a surrounding liquid or rub off on any packaging
materials. Binding agents can include sugars, carbohydrates,
proteins, methyl cellulose, and other materials commonly used to
bind food colors, coatings, frostings, sprinkles and the like. The
binding agent can be co-mixed with the chromic material, coated
after application of the chromic material to form a protective
layer, or used in combination with both the food and the chromic
material.
[0073] Various traditional, inactive ingredients can be used to
co-mix, pre-color or adhere the chromic agent to a support surface
on the consumable product including: hydroxypropyl cellulose,
hydroxypropyl methyl cellulose, microcrystalline cellulose, starch,
red iron oxide, magnesium stearate, titanium dioxide, talc,
colloidal silicon dioxide, polyethylene glycol, various synthetic
polymers, Yellow 10 dye, carnauba wax, corn starch, sodium starch
glucolate, or the like. These various additives are conventional
and will be present, when employed, in a range of from about 0.1 to
95 weight %.
[0074] Configurations of application for chewable foods: The
chromic material, such as diacetylenes, need to be in a
microcrystalline phase in order to polymerize to the chromic
material. Therefore, if the diacetylenes are to be mixed with other
components that adversely affect the formation of the
microcrystalline phase, the diacetylenes will normally be
prepolymerized before formulation. Solution phase chromic material
or monomer can be applied to a chewable food surface, dried and
then polymerized. Liquid phase monomer can be polymerized if in a
colloidal/crystalline form, applied to a solid food surface, and
dried. Solid microcrystalline monomer can be admixed with food
carriers, applied to a solid food surface, and then polymerized.
Solid microcrystalline monomer can be first admixed with a food
carrier, polymerized, and then applied to a food surface. Solid
microcrystalline monomer can be first polymerized, admixed with a
food carrier, and then applied to a food surface.
[0075] The solid surface of the food may be processed to accept the
monomer or chromic material. In many cases, if the food surface is
too porous the monomer or chromic material will dissipate into the
interstitial spaces below the surface, rendering it unavailable for
visualization. Solid food surfaces can be prepared for accepting
the monomer or chromic material by modification of the food
composition or coating the surface with a composition, which seals
the food surface. In either case, application of the monomer or
chromic material to the food surface will provide for a means to
keep the material on the surface and visible. Illustrative of such
situations are sugars, proteins, digestible celluloses,
methylcellulose, polydextrins, digestible waxes and gums, which can
also be used to create a smooth hydrophobic barrier for even
coating of the physiochromic agent.
[0076] Structures containing the physiochromic agent can be created
which come in contact with the food type of interest. The
structures themselves can be compatible with food and can be made
with digestible components or can be made of material that is
certified for contact with food but not meant for consumption.
Structures can be labels, part of the package, an insert in the
package, paper rings, tabs or the like. The structures can be
printed with the physiochromic material in a way in which the
structure can interact with the food. For example, the structure
can be an adherent label containing a thermochromic form of the
agent. The adherent label can be adhered to a food type meant for
heating. When the food is heated, the thermochromic agent will
change color. If the label structure is edible, it can remain in
contact with the food type and be consumed along with the food. If
the structure is safe for food contact but not edible, it can be
part of a packaging material or removed prior to consumption.
[0077] The monomeric or polymeric form of the chromic agent can be
fused or admixed into foods or medications. For example, a
polymerized liposomal or colloidal form of polydiacetylenic
material can be processed with gelatin to produce a thermochromic
form of desert gelatin. At refrigerator temperatures (40.degree.
F.), the gelatin could appear dark blue. When raised to room
temperature (68.degree. F.), the gelatin would turn bright
red/orange. Alternatively, a polymeric chromic agent could be cast
into a throat lozenge. A chromic agent that undergoes a temperature
transition from dark blue to red/orange at 100.degree. F. could be
employed to help a consumer determine if they have a fever. Usage
of the lozenge would indicate to the consumer that they have a low
grade fever if the lozenge turns red/orange. The consumer could
also examine his tongue to see if either a red or a blue color has
come off the lozenge. Blue would indicate no fever and red/orange
would indicate a low-grade fever. Similarly, chromic change agents
can be incorporated in tablets, pills or other medications
formulated to be taken by a sick patient, and can indicate the
presence of a fever by a color change, which remains with or comes
off the medication.
[0078] The thermochromic material can be patterned alone or in
combination with food-based inks to create bar codes. Bar codes can
be utilized in connection with cooking where the cooking system,
equipped with a bar code scanner, can measure a change in the bar
code as the code is exposed to high temperatures. Bars on the code
can be made to change color when one or more temperatures are
achieved. The optical density change in a given bar will result in
a prescribed change and interpreted by the measuring system to
indicate a specific temperature. The bar code can indicate doneness
or in process cooking. The bar code can be printed directly on the
solid food type or on the food packaging. This allows the bar code
and bar code reader to be used as a temperature measure device.
[0079] Methods for triggering color change: The chromic change can
be tailored to match a desired effect or outcome in a particular
food or ingestible. Color change triggering processes can include
temperature, pH changes, changes in ionic strength, mechanical
changes such as stress or pressure during mixing or contortion,
chemical changes such as the addition of a second component,
exposure to light for a photochromic effect, biochemical reactions
such as binding pair interaction, solvent environment changes,
hydration or dehydration, solvent changes, and enzymatic changes
where enzymes in the food can induce a change. The methyl or ethyl
ester of 10,12-tricosadiynoic acid or 10,12-pentacosadiynoic acid
is made by standard esterification in methanol or ethanol
respectively. The ester compound can be applied to foodstuffs,
crystallized and then polymerized at or below room temperature.
[0080] Physiologic changes in pH, ionic strength, or hydrogen
bonding agents can be used to alter the state of the chromic
material, which may be induced by finger touch or contact with
saliva. Saliva is relatively acidic and can be used to induce an
acidic environment which can cause a chromic change in foods
containing the chromic material. The dark chromic material is
extremely sensitive to thermal contact and changes color
immediately at 70.degree. F. for the tricosadiynoate ester and at
80.degree. F. or above for the pentacosadiynoate ester. The chromic
material can be sensitized to respond to physiologic temperatures
(i.e., about 98.degree. F. for humans).
[0081] Physiochromic matrices can be formulated to hold the chromic
agent in one state until the matrix is dissolved. Once the matrix
is dissolved and its effect on holding the chromic agent in one
state, the chromic agent is free to change conformation to another
state. For example, an acid sensitive, pH reversible physiochromic
agent can be dried down with an acid. The acidity can hold the
polymer in one colored state. The local concentration of acid is
high in the dry state. When a physiologic buffered solution is
added, the acid is released and neutralized by the buffer. The
physiochromic agent can now covert to an alternative color since it
is bathed in a basic environment.
[0082] Combination colors can be integrated along with the chromic
material to create a variety of color change effects. For example,
the brown color used in a variety of food types is made with a
combination of yellow, red and blue. The blue food color can be
replaced with a blue form of the chromic agent. Upon color change
triggering, the brown food color combination can be converted to a
bright red-orange. Examples of brown colored foods or beverages
include brownie mixes, hot and cold chocolate drinks, cinnamon
colors, and the like.
[0083] The physical, conformational, or polymerization state change
can be used as a mechanism to release or change certain embedded
flavors, nutrients, aromatic compounds, nutraceutical agents or the
like. For example, a flavor material can be chemically coupled to a
monomer non-chromic form compound. In the monomeric form the
compound-flavoring expresses a flavor, whereas upon polymerization
the monomer becomes polymerized, consequently restricting the
flavoring to interact with taste receptors. The restricted form of
the flavoring becomes non-flavored. The release mechanism is
simultaneously traced with a physiochromic color change as an
indicator.
[0084] Alternatively, conformational changes in the chromic
material matrix can be utilized to release various food grade
compounds. For example, polydiacetylene in its blue form is highly
ordered on the molecular level. During processing and
polymerization, a food grade compound such as a vitamin or flavor
can be trapped. Upon temperature or physiochromic triggering of the
polydiacetylenic material to the red form, the polydiacetylene
becomes disordered and opens at various positions. During the
conformational disordering of the polymer, the vitamin or flavor
can be released. The monomeric form of the chromic material can be
used to absorb and allow in the flavor or aroma. Polymerization
could be used to trap in the flavor or aroma. The ordered blue form
of the polymer may hold a flavor or aroma where heating results in
a conformational change and disorder in the polymer which is useful
to release the flavor or aroma.
[0085] Specific physiochromic changes may be desirable when
developing foods that a producer would like to differentiate from a
competitors. Binding moieties can be used to facilitate specific
photochromic, thermochromic, or physiochromic color transitions.
Lectin-receptor agglutinin-receptor, antibody-antigen,
biotin-avidin interactions or the like can be used to stimulate a
binding pair interaction between different food components. Binding
pair interactions can be used to create specific colorimeter
changes in the chromic agent. For example, a combination of milk
and cereal can be formulated in which a specific type of milk
contains one member of a binding pair, such as a multiple
biotinylated milk protein and the cereal contains a biologically
active form of the physiochromic agent that contains avidin or
streptavidin as a second member of the binding pair. When the
specific milk comes in contact with the specific cereal, then only
that milk will cause the specific cereal to change color through
the binding interactions of the binding pair members. No other milk
or cereal combinations could cause a chromic change without the
selective interactions of those binding pair members. This scenario
can help food manufacturers create novel means of brand
differentiation.
[0086] Carbonation pressure release in opening sealed carbonated
beverages may be used to induce a local stress/concentration
change, which could cause a color triggering changes in the chromic
material. For example, the inside of a liquid container can be
coated with a pH or friction sensitive version of the physiochromic
material. Upon opening the container and release of built up
pressure to ambient conditions, the process of bubble nucleation
and local carbonic acid concentration change may be used to cause a
change from environmental condition/conformation of the color
change agent to another form of the material. If the container is
clear, the color change can be made evident to the observer of the
color change. The color change agent can either be in a water
solution form such as contained within a liposome structure or be
coated on the inner wall of the container.
[0087] For hydration-activated color change, physiochromic agents
which change color depending on the degree of solvation or
hydration can be used (hydrochromic agents). Color change agents
capable of changing color upon partial or complete hydration and
can be ingestible can find multiple uses for food or food related
products. For example, the bi-polar diacetylenic compound
4,6-decadiyne-1,10-diol when adhered to a surface and polymerized
at room temperature forms a deep blue/purple polymer. The
blue/purple polymeric form of the material changes to a red/orange
color upon hydration below or above the melting transition of the
material. One mechanism for inducing the color change may be rapid
intercalation of water between the layers of the crystalline
lattice where the aqueous phase disrupts the ordered polymer
lattice.
[0088] The hydrochromic agent's rate of color change is temperature
and configuration dependent. For example, the rate of color change
from the blue/purple color to a red/orange color is rapid and
occurs within a minute when a thin layer of the hydrochromic agent
is uniformly spread over a dry porous structure and exposed to an
aqueous fluid at or 10.degree. F. below the melting transition of
the material. The color change is slowed significantly from one to
several hours if the hydrochromic agent is applied in a thick layer
(0.1 to 1.0 mm) and treated with an aqueous solution near
freezing.
[0089] The hydrochromic agent can be placed on an ancillary
material such as carbohydrates, granulated sugar, sugar sprinkles,
fondant, sugar pastes, candies, nutritional bits, food coatings,
condiments, carriers, emulsifiers, coating materials or the like
and subsequently applied to a food surface. For example, the
diacetylenic compound 4,6-decadiyne-1,10-diol can be conveniently
dissolved in an alcoholic solution (0.15 g/ml) and the solution
applied to white or colored sugar sprinkles. Upon coating, drying
and polymerization, the sugar sprinkles can subsequently be adhered
to a cookie, cereal, candy, bread, cake or the like. The dark
blue/purple sprinkle changes to an orange/red color immediately
upon treatment with water, milk or other liquids capable of
disrupting the crystal packing of the chromic agent.
[0090] The use of hydrochromic agent pre-coated sugars, salts or
other carriers has the advantage of providing a high degree of
coloration and surface area for fluid contact. For example, a fine
hydrochromic/sugar particle coating creates capillary channels for
fluid to wick through, thereby facilitating the hydration
process.
[0091] Other structures may also conveniently contain the
hydrochromic agent placing it in close or intimate contact with
foods. For example, the material can be placed on a bowl, spoon,
plate, fork, straws, a hydrating strip, a package insert, part of
the package or the like, such that a portion of an absorbent
material can be in liquid contact with an ingestible liquid. As the
liquid hydrates the structure, the liquid solvent hydrates and
migrates along the structure causing the physiochromic agent to
change color. If the structure containing the agent is edible, it
can remain in contact with the ingestible liquid and be consumed.
If the structure containing the agent is safe for contact with
food, but inedible, the structure can be removed prior to
consumption of the ingestible liquid.
[0092] Mechanical/frictional means can be used to induce color
changes in a variety of food compatible products. Color changes can
be induced using mechanical means primarily including friction due
to rubbing, elasticity, and shearing. For visible friction-induced
color changes, the color change agent can be permeated into or
placed on a surface. Rubbing, stretching, and shearing or other
stress-causing action also can be used to induce a frictional force
on the color change agent resulting in localized heating. The ease
and magnitude of color change is dependent on the transition
temperature of the chromic agent, the friction coefficient between
the molecules in the composite or a rubbing tool and the thermal
insulative/conductive properties of the composite or rubbing tool.
Rubbing tools can include a person's fingers, finger nails, teeth,
a wooden stick, a plastic implement or the like. Materials that are
more thermally insulative may result in more thermal energy
remaining with the chromic agent and less being transferred to the
composite or rubbing tool. Metal rubbing tools serve as poor
devices for inducing a frictional color change, whereas insulative
materials such as plastic or wood provide an easier means for
inducing a color change.
[0093] Mechanical/frictional color change methods are attractive
for revealing messages, altering graphics, introducing codes,
creating sweepstakes, creating entertaining graphics or the
like.
[0094] Touching, rubbing mixing, chewing, kneading and various
other forms of handling can be used to induce the color change. The
color change agent must be responsive to the available amount of
frictional forces. The agent must also be stable to ambient
temperatures and humidity conditions or a color change may result
from influences other than frictional/mechanical forces. An
exemplary compound, the blue polymeric form of
10,12-octadecadiynoic acid exhibits good thermal stability up to
100.degree. F. with full hydration, whereas rubbing the dry form of
the blue polymer easily triggers the polymer to the red form of the
polymer.
[0095] Mechanical/frictional triggering can be performed directly
on a food surface, on a laminate in contact with the food or on a
generic surface. In each case, the triggering process can be used
to reveal hidden messages, illuminate branding messages, provide a
means of interactive graphical changes or the like.
[0096] The mechanochromic material can be applied to a surface by a
variety of means including application of a solvent containing the
chromic agent by means of ink jet printing, spraying offset
printing processes, blotting, pad printing, dipping or soaking.
Concentrations of the chromic agent can be from about 2 g/ml to
0.01 g/ml, typically in the range of from about 1 g/ml to 0.05
g/ml, usually from about 0.5 g/ml to 0.1 g/ml. Alternatively, the
chromic agent can be applied using transfer methods such as thermal
transfer, rubbing from a solid, from a molten liquid or the
like.
[0097] Photoactivation can be used to cause color changes in foods
or food-related products when an appropriate photochromic agent is
introduced. Convenience foods containing a photochromic agent when
placed in sunlight provide an entertaining means to create a
variety of effects. For example, cookies, cereals and various other
convenience foods can be used to reveal, various logos, branding
identities, codes, sweepstakes information, messages or
co-merchandising items to the consumer.
[0098] The photochromic agent can be patterned on or applied to the
food, packaging material or implement in contact with the food by
means disclosed earlier. Photochromic agents have the advantage of
not requiring incidental heat of fluids to create a visual effect.
Depending on the photochromic agent, the food can either turn from
a natural food color to a new hue or from a given hue to an
alternate hue.
[0099] For thermochromic agents, temperature ranges can include
cold temperature for frozen and then thawing (-20.degree. F. to
above 32.degree. F.), low temperatures from refrigerator levels to
room temperature (33.degree. F. to 60.degree. F.), moderate room
temperatures to moderately above room temperature and overlapping
temperatures from (61.degree. F. to 100.degree. F.), and room
temperature to moderate to high cooking temperatures (70.degree. F.
up to 200.degree. F.). The final temperature triggering range for
the chromic agent is dictated by the hydrocarbon chain length of
the molecule, the intermolecular hydrogen bonding capabilities of
the molecule's head group, additional side chains of moieties which
influence intermolecular attractions or repulsions or the like,
environmental effectors which impact the final temperature
triggering transition for the chromic agent, and the degree of
polymerization to which the chromic material is exposed. Guidelines
can be given, but for a particular transition temperature change,
the actual change must be determined experimentally. One can try
different amounts of the effectors and graph the effect of the
concentration of effectors with the change in transition
temperature. A curve is produced which allows the determination of
the amount of effector, with the change in transition
temperature.
[0100] Environmental effectors combined with chromic agent to
increase or decrease the thermochromic transition of a given
thermochromic agent include: various oils, waxes, low levels of
organic solvents such as alcohols, ketones, ethers, chloro- and
fluorocarbons, metal ions and other ionic compounds, chelating
compounds, emulsifiers, or the like. The effector material can
change thermochromic transition by altering the energy required to
induce a thermochromic transition in the agent. Oils and organic
solvents can interact with the long chain hydrocarbons of a C23 or
C25 polydiacetylenic acid. The chain packing can be disrupted by
the effector to create a metastable state in the polymer that can,
in turn, change color at a lower temperature. For example, the
temperature transition can be lowered for a polymerized C25
polydiacetylene polymer in its native dry crystalline state from a
temperature range of 150.degree. F.-170.degree. F. (depending on
the degree of polymerization) down to 120.degree. F.-130.degree. F.
by suspending the crystals in a sugar syrup and adding trace
amounts of ethanol. Concentrations of oils or solvents added to a
matrix can be from 0.001% to 100%, based on 100% of diyine, more
usually from 0.01% to 50%, and typically from 1% to 10%.
[0101] The melting transition of the wax or oil in contact with the
chromic agent can directly increase or decrease the intrinsic
transition temperature of the chromic agent. Oils that solidify
under freezing temperatures can stabilize the chromic agent. Upon a
temperature increase above melting transition temperature of the
oil or wax, the melting process can facilitate the melting of a
hydrocarbon side chain on the chromic agent, causing it to undergo
a thermochromic transition. The final thermochromic agent
triggering temperature can be further adjusted by selecting a
specific temperature at which polymerization of the chromic agent
is performed. Polymerization at subzero temperatures (-10.degree.
F.) lowers the final triggering temperature relative to
polymerization at temperatures just above freezing (10.degree. F.).
Thermochromic transition temperatures can be increased by
increasing intermolecular stability, such as promoting hydrogen
bonding of hydrophobic interactions, both between monomeric units
within a given thermochromic polymer chain and between the polymer
chain and a given effector molecule. For example, the transition
triggering temperature of a C23 or C25 polydiacetylenic acid
polymer can be increased by embedding the polymer in a high
temperature-melting paraffin or wax. The thermochromic material can
be embedded in waxes from a concentration of 0.01% to 99%. More
usually from 0.1% to 50% and typically from 1% to 10%.
[0102] Alternative chromic agent triggering mechanisms and color
reporting processes: Alternative triggering mechanisms include the
use of enzymes or pre-digestive effectors primarily from saliva
which can chemically or biochemically induce a color change in the
chromic agent through a catalytic change. For example, enzymes
responsible for the initial stages of starch break down occur in
saliva. Chromic agents chemically modified with starch or
carbohydrate chemistries can be made susceptible to enzymatic
activity resulting in a conformational or environmental change
which in turn can cause a color change in the chromic agent.
[0103] Microbial metabolites, enzymes, or by-products find use as a
triggering mechanism for the chromic agent resulting in a means to
detect certain bacteria in foods. For example, the chromic agent
can be chemically modified to respond to certain by-products
produced by Salmonella. The chromic agent is placed near or coated
on the inner surface of a wrap that is in contact with a processed
chicken carcass. If Salmonella is present in the carcass and
produces a triggering compound the chromic agent is triggered,
indicating the presence of Salmonella.
[0104] An alternative mechanism for microbial detection is the use
of a the microbial cell's uptake of monomer forms of the chromic
agent. For example, E. coli can use diacetylenic fatty acids as a
carbon source. Incorporation of the polymerizable acid into a
bacterial cell membrane can be detected by ultraviolet irradiation
of the bacteria resulting in polymerization of the acid to a blue
color. Food processors can simply irradiate food; development of
blue color indicates the presence of harmful bacteria.
[0105] Importantly, polydiacetylenic materials as a class of
intrinsic chromic change agents can be selectively tuned to respond
to specific triggering processes relevant to ingestible products.
Additionally, polydiacetylenic materials can uniquely undergo
multiple different sequential color changes. Examples include
photochromic triggering followed by irreversible thermochromic
triggering; photochromic triggering followed by reversible
thermochromic triggering; photochromic triggering followed by
mechanochromic triggering; reversible thermochromic triggering
followed by irreversible chemochromic triggering; multiple
thermochromic transitions during increasing or decreasing
temperature exposure; and other permutations.
[0106] Configurations for liquids: Liquid phase monomers can be
included in an unpolymerized form in a beverage or consumable
fluid, such as in a syrup where the monomer is in a colloidal or
microcrystalline state. The monomer can be directly polymerized
with an ultraviolet light source or sunlight. The solution
suspension monomer can also be pre-polymerized and then added to a
liquid phase consumable. The monomer can be made water-soluble
using short chain compounds, which are mono- or bi-polar. In this
case, the monomer must be prepolymerized in a solid form and then
solubilized after polymerization. Polydiacetylenes undergo a
topochemical polymerization and must be in a crystalline state in
order for polymerization to occur. Monomeric lipophilic forms of
diacetylenic compounds can form colloidal particles, such as
liposomes, vesicles, or other lamellar forms. Lipophilic forms of
the monomer can be crystallized in a colloidal state and
polymerized while the monomer is suspended in an aqueous solution.
Colloidial or microcrystalline suspensions of monomeric diacetylene
can be made using ultrasonication or standard reverse phase vesicle
formation methods. Heating and cooling cycles along with intense
sonication can be useful for improving uniformity and homogeneity
of the suspensions.
[0107] For alcoholic beverages, the monomer can be processed into
the beverages using reverse phase vesicle formation. The monomer
can be dissolved in ethanol and combined with the beverage aqueous
constituents. Vesicle formation can be accomplished using standard
processes. After the beverage has been formulated, polymerization
of the monomer can be accomplished using standard polymerization
methods.
[0108] Methods for application to foods: Compositions containing
either pre-polymerized material or monomer material can be
processed into foods using a variety of application methods such as
ink jet printing, pad printing, extrusion, spraying, liquid
applicators, dip coating, sublimation, spreading, application of
laminates containing the material such as sugar layers or rice
paper, edible labels, dripping, dye sublimation printing or the
like. The method of interest will depend on the food substrate
utilized, the composition to be applied and the desired format in
which the composition is to be placed.
[0109] Coating Matrices and coating methods for sugars, salts,
shredded and powdered cheese, flower, grains, nonpareils, and other
powdered forms of foods. Polyethylene glycol coating matrices for
cereals and cookies are practical due to the unique solubility
properties of polyethylene glycol polymers.
[0110] Co-coating matrices can have the combine properties of
helping to adhere the chromic agent to a food type, suspending the
chromic agent in a matrix to maximize the visual appearance of the
chromic agent, helping to modulate the activity and performance of
the chromic agent, helping to minimize the amount of chromic agent
required, and the like. For example, the coating matrix can have
the property of allowing the chromic agent to undergo a
conformational transition from one color to another by providing
the necessary flexibility required by the chromic agent.
[0111] The coating matrix can also provide a source of inducing
defect structures in the solid phase of the chromic agent or as a
means for introducing doping agents along with the chromic agent as
enhancers to improve the agent's optical performance. Doping agents
can be used to enhance the optical properties of irreversible and
reversible chromic agent changes. Low levels of additives can be
used to enhance the colorimetric changes that the material can
undergo. Doping materials can include chemically/structurally
related compounds which help create a molecular environment
favorable to the transitions necessary for the chromic agent to
undergo changes during its transition from one color to
another.
[0112] The coating matrix can also help provide a protective
barrier for the chromic agent by minimizing the unwanted effects
due to oxidation, moisture, or stabilization of the chromic agent
of effectors of the chromic agent during storage and shipment of
the final end product to the consumer or during product
production.
[0113] Coating matrix solutions can be made using a variety of
solvents including polar protic solvents such as water ethanol and
methanol, apolar organic solvents such as dichloromethane, polar
aprotic solvents such as acetone, or the like. It is desirable to
use solvents that are considered food grade such as non-denatured
ethanol.
[0114] For application to cereals, it is desirable to place the
photochromic, thermochromic, or physiochromic material in a carrier
material such as a sugar matrix whereby the matrix is applied as a
coating to the cereal during production. For application to
convenience foods such as flat pastries or cookies where patterning
is important, high-speed printing techniques are important. In this
case it is desirable to use a soluble form of the material so that
it can be incorporated directly into the liquid matrix used for
printing.
[0115] The monomer or polymeric material can be applied to a solid
food using a laminate overlay where the base material in the
overlay/laminate is itself edible and contains the monomeric or
polymeric color change material. Rice paper can be used as a
laminating material which when wetted and containing the polymer
can be easily adhered to the food as a substrate. Laminates can
contain the chromic agent in combination with sugars,
carbohydrates, digestible polysugars, or proteins, which give the
laminate a stable layer. The layer can have the property of being
directly layered on to a food surface, fused and then activated for
photochromic, thermochromic or physiochromic activity. Food
laminates capable of containing the chromic material can be any
commercially available product or formulation that is
physiologically acceptable and can be printed or coated. For
example, the laminate can be a marzipan sheet available through
most bakery supply sources. The thin sheet can be printed, stamped,
blotted with the chromic material by any convenient means, dried
and polymerized. The laminate can then be adhered to the food type
surface alone or with food pastes.
[0116] Commercially-available laminate/paper materials compatible
with ink jet printing can be used (Kopykake, Torrance, Calif.).
Commercially-available ink jets can be modified to contain an ink
version of the chromic agent. The ink jet cartridge can be used
with an aqueous or solvent-based solution containing the chromic
agent. The food grade laminate/paper can be inserted into the ink
jet printer and standard ink graphics printing programs utilized to
generate text and graphics. The laminate approach provides a means
for generating high-resolution graphics and text and transferring
the images or text directly to the food type. The laminate can be
made to be compatible with the food flavor and texture. For
example, it is desirable to have a sugar-based laminate for sweet
products such as pastries, cookies, and certain convenience foods.
Alternatively, it is desirable to have a salt/seasoning-flavored
laminate for dairy or processed meat products. The exact
composition, flavor, and texture of the laminate will depend on the
food component into which the chromic material is integrated.
Laminates have the advantage of being separately prepared from the
food product and then processed to be a part of the food. Parallel
processing provides for high-speed production and simplified
implementation.
[0117] Edible food grade labels, paper or wrappers containing the
chromic material can be used for a wide range of general
applications. The label can be made with a digestible carbohydrate
material rather than a non-digestible cellulosic material. Printing
the chromic material can be accomplished by standard printing
means. The printed chromic label can be applied to any solid and
reasonably flat surface such as a cookie, a toaster pastry, baked
goods, and a variety of convenience foods. A major advantage to
chromic labels is that they can be pre-mass produced and
subsequently applied to finished foods rather than requiring
changes in existing food production processes. The chromic material
can made soluble in ethanol or various highly volatile solvents,
which can be quickly evaporated, or in an aqueous solution, which
can be absorbed. In any case, it is desirable to coat the surface
of the food substrate with the chromic material so that upon
polymerization the chromic material is highly visible. The
substrate can be dipped into a solution containing the chromic
agent, thereby coating the agent on the substrate's surface.
Entertainment foods such as marshmallows can incorporate the
chromic material using dip coating or spraying processes to provide
an extra level of enjoyment, especially for children. Chromic
marshmallows can be produced to respond to ambient temperatures
such as touch or elevated temperature fluids, like hot chocolate.
Marshmallows can be directly dip coated with a higher temperature
thermochromic material dissolved in an alcoholic solution. After
drying and polymerization to produce the dark colored chromic
agent, the marshmallows would remain dark until exposure to high
temperatures such as an open flame. Upon exposure to any elevated
temperature, the dark marshmallow would turn bright orange-red.
[0118] Alternative means of incorporating the chromic agent into
foods could include biochemical substitution. Fruits, vegetables,
certain meats, bacterial cultured dairy products such as yoghurt,
grains, rice, beans or other amenable foods can be grown with the
precursor monomeric material as a nutrient for the growing food.
Upon incorporation or biochemical uptake of the precursor monomer
through the appropriate pathway into the food product, the food can
be irradiated with ultraviolet (254 nm) to cause polymerization of
the foodstuff. Various dairy products such as cheeses, milks, and
yoghurts that naturally contain bacterial cultures to aid in
digestion can be made with monomeric and/or polymeric chromic
agents.
[0119] Spectral colors relating to chromic change agents: The
color, contrast, and hue can be adjusted to give a chromic change
agent particular visual characteristics. Color change
characteristics can be achieved by changes in the chromic agent
itself or in combination with stationary base colors associated
with the same matrix as the chromic change agent. Various
permutations of base colors in combination with the initial color
of the chromic change agent will give one visual color to start
with and often an unexpected color with which to finish. Chromic
change agents with chromically reversible properties can be used to
achieve repetitive visual effects compared to irreversible chromic
change agents that can be used to achieve a one time effect.
[0120] Standard Pantone Colors, RGB, CMYK and colors typically used
in the food industry can be used in combination with the chromic
change agent. Examples of color change options based on the change
of the chromic agent alone (white or clear base color) or in
combination with a other base colors listed below but are not
limited to any specific example are shown in Table 1.
[0121] In addition, color additives such metallic flakes, glitters,
sparkles, and other elements which augment colors, can be used to
create desirable visual effects. For example, silver coated
non-pareils can be coated with a red reversible form of the chromic
change agent to give the effect of a shiny red anodized sphere.
When the combination is cooled, the coated non-peril appears to
have a dark blue metallic anodized coating.
TABLE-US-00001 TABLE 1 Color change options based on initial
chromic color and base color. Initial Starting Triggered Chromic
Color Base Color Combination Color light blue white/clear light
blue pink medium blue white/clear medium blue orange dark blue
white/clear dark blue red/orange magenta white/clear magenta red
magenta white/clear magenta blue red white/clear red blue red
white/clear red yellow yellow white/clear yellow red blue yellow
green orange pink yellow magenta green red yellow orange brown
orange orange dark orange dark brown orange light blue purple dark
blue orange light green red/green gray green orange pink red purple
red tan deep red blue/purple light blue light green gray green
red/green yellow red orange red yellow light tan golden brown red
light blue brown orange red light green brown navy blue
[0122] Food grade metallic and pastel colorants (Linton Paper &
Supply, Inc.) can also be used in combination with the chromic
change agent to give a sparkle-like effect. More granular colorants
can be used to give a matte-like finish to the coating.
[0123] Methods for polymerization: Polymerization can be
accomplished either prior to processing with the food or after the
monomer has been processed with the food. The photochromic
properties of the chromic material can be used to create patterns
and messages on the surface of solid foods. Increasing or
decreasing the level of polymerization of the chromic material is
used to increase or decrease, respectively, the temperature or
other means of inducing color changes in the polymer:food matrix or
the like used to trigger a chromic change in the material. For
example, different zones of a food surface, which contains the
chromic material, can be polymerized to different levels. Each zone
can, depending on the level of polymerization exposure, change
color sequentially as the temperature rises. The chromic change
zones can tell consumers that cooking is in progress but not yet
done. As cooking continues and as the last zone changes color, the
consumer can ascertain that cooking is complete.
[0124] Zones which change colors at increasing temperature can be
used for food safety purposes indicating to preparers or consumers
when the food is cooked to a temperature level and any
contaminating bacteria have been killed (e.g., 160.degree. F.).
Zones would be calibrated to accommodate higher external
temperatures during cooking.
[0125] Increasing or decreasing the localized concentration of
chromic material in combination with controlling the local level of
polymerization can be used to create complex patterns on the
surface of a food type. Increasing the local concentration in one
area relative to another area will create a higher relative
triggering temperature in the high concentration zone relative to
the lower concentration zone. The patterns can be developed to
create the visual appearance of a changing graphic throughout the
temperature triggering process.
[0126] In addition, standard food colors can be used in combination
with the chromic material to create full color designs and
patterns. The visual representation of a graphic that changes color
and apparent pattern throughout the heating process can have
significant value in that it can be used for commercial,
promotional, merchandising and advertisement purposes. In some
cases, polymerization can be accomplished by the consumer where, by
opening a package and placing the foodstuff in sunlight, a color
begins to appear immediately prior to consumption. For example,
drinks or cookies can be made to change color in the sun. In other
product formats, the photochromic food may be purchased along with
an appliance or hand held ultraviolet lamp which can be use to
expose the photochromic material.
[0127] Thermal polymerization can be utilized in certain foods.
Thermal polymerization provides for photochromic color development
of the chromic agent without the need for an external ultraviolet
light source. Certain forms of diacetylenic compounds that are
highly ordered, yet provide flexibility for reorganization, can
self-initiate polymerization under mild conditions. For example,
the crystalline form of the methylester of 10,12-tricosadiynoic
acid will polymerize in the dark and in absence of ultraviolet
light. The thermal polymerization temperature may be substantially
different from the thermal color change transition temperature.
Polymerization may occur at a lower temperature, e.g. 10-20.degree.
F., than the thermal transition temperature.
[0128] Patterns in the chromic agent can be generated by
selectively placing the agent in locations using methods such as
ink jet, pad, extrusion or offset printing followed by
polymerization of the chromic agent. Alternatively, the patterns
can be generated using a continuous evenly coated area of the
chromic agent followed by photo-masking techniques. Ultraviolet
light-transmitting photomasks can be utilized. In either case,
high-resolution graphics and line art can be generated directly on
the food surface.
[0129] Ingestible chromic change particles dispersed throughout
ground meats as an intrinsic internal thermometer: The United
States Department of Agriculture now recommends not using the color
of cooked ground meats to determine doneness and whether or not
that the meat has been cooked to a safe level (greater than
160.degree. F.). The chromic change agent can find use as an
element dispersed throughout ground meat that turns color only when
the center of the ground meat has reached an internal temperature
of 160.degree. F. The chromic agent can be coated on any compatible
food grade additive that can be admixed with the ground meat prior
to cooking. The chromic change agent/additive can be introduced
into the ground meat at the meat processor level or by the consumer
immediately prior to cooking. Chromic change agent particles can be
dispersed into ground meats at a concentration that allows the
particles to be visualized any time the meat is exposed when cut
open. The chromic change agent particles can be dispersed at a
concentration of one per centimeter cubed to a concentration of
1000 per centimeter cubed. More often the chromic change agent
particles can be dispersed at a concentration of 10 per centimeter
cubed to 500 per centimeter cubed. Usually, the chromic change
agent particles should be present from a concentration of 25 per
centimeter cubed to a concentration of 100 per centimeter cubed.
Chromic change agent particles obviate the need for thermometers
since the meat itself can posses the temperature sensing
capability. The cook or consumer need only cut into a piece of meat
during cooking to determine accurately the internal level of
doneness of the meat being cooked.
[0130] Ingestible chromic change particles integrated into foods
may find broad use in cooking or warming other items as well. For
example, they can be used for baked goods, in food service for
monitoring holding temperatures, processed, precooked meats such as
hot dogs, in food processing, in microwaveable foods, and various
other related products or processing.
[0131] The chromic change agent can be conveniently coated onto a
particle such as a spice, sesame seed, oatmeal flake, protein
particle, soy based particle, carbohydrate particle or any other
food compatible matrix particle that is of size which can be
identified by eye. The chromic change agent can be coated as a film
on the surface of the particle to give the particle a
characteristic color that is differentiated from the ground meat
with which it is admixed.
[0132] Chromic change agent particles can range in size and shape.
Typically the chromic change agent can be a sphere, a disc, egg
shaped, a flake, a random globule, a ring, various geometric
shapes, a rod or noodle shape, or the like. The chromic change
agent particle can be as small as a 0.5 millimeters along its
longest axis so as to be visible by eye to as long as sever
centimeters. More usually the chromic change agent will one to 10
millimeters along its longest dimension and typically 2-5
millimeters in length.
[0133] Chromic transition conformational change as a depot release
substance: The chromic transition may be used as a releasing
mechanism for nutrients, vitamins, ingestibles, drugs or the like
base on the structural change that it can undergo when it is
triggered from one color to another. For example, polydiacetylenic
material is known to undergo a significant conformational change
during its transition from one color to another. The blue form of
the polymer is well ordered system comprised of parallel strands of
extended and conjugated double and triple bond units. Side chains
and substituents are ordered along with the polymer backbone in a
lattice structure. When the ordered macromolecular structure is
chromically triggered, it becomes disordered and an open lattice.
The chromic change mechanism can be used as a means to release a
substance embedded within the lattice matrix. Opening the matrix
can be used to release the embedded constituents. The chromic
process has a dual function: first, it can act as a releasing
mechanism and second, it serves as a color change indicator as to
when the release occurs.
[0134] Wording or graphics printed on the side of over-the-counter
or prescription drugs can be printed with a low temperature
irreversible thermochromic material, indicating to the consumer,
pharmacist or medical specialist that the drug has been stored at a
safe temperature or has been spoiled at a higher temperature.
[0135] A chromic change agent may be incorporated into throat
lozenges to tell the consumer that they have an elevated body
temperature or fever. Alternatively, an aqueous form of the chromic
material can be added to a mouthwash, spray or gargle that changes
color if the user has a fever.
[0136] Alternative thermochromic materials: Alternative
thermochromic materials that may have application as ingestibles
include leucodyes, transition melting waxes, pigments that are
released during hydration or shear, micro and nano-pigments,
molybdenum, doped or undoped vanadium dioxide, mercuric iodide,
indolinospirochromenes, spiropyrans, polythiophenes,
polybi-thiophenes, di-b-napthospiropyrans or the like. Alternative
chromic change agents can be combined with food matrices using
methods described earlier. Methods for the preparation of
spiropyrans, including (Keum et al. (1995), Bull Korean Chem Soc
16: 1007), polythiophenes (Levesque et al. (1996) Chem Materials 8:
2843) and various other chromic change agents (Brown et al., eds.,
(1972) Photochromism, in Techniques of Chemistry, Vol. 3; Durr et
al., eds., (1990) Photochromism: Molecules and Systems (Studies in
Organic Chemistry, 40)) have been described. All of these above
references are incorporated herein by reference. Extensive
modification or encapsulation may be required with compounds such
as these to ensure safe ingestion and consumption without toxic
side effects.
[0137] Compounds such as spiropyrans and the like are of interest
where the thermochromic change agent exhibits a color at one
temperature and disappears when the temperature is altered.
Spiropyrans, polydiacetylenes and other related materials that
change color or become transparent can be used to reveal messages
or graphics when overcoated on a permanent pigment. Making messages
appear or disappear is of interest to the food and entertainment
industries for promotional, marketing, and sales programs.
[0138] Combinations of different chromic change agents: In some
cases, multiple color changes may be desirable or required on some
products. Different chromic change agents or classes of agents that
change color in response to different triggering mechanisms may be
used on a single product as distinct pH indicators, time
temperature indicators, dissolved gas color indicators, ionic
strength indicators, moisture indicating materials, chemical color
change indicators, various photochromic materials, various
thermochromic materials, various mechanochromic materials, or the
like. Combinations of polydiacetylenes, indolinospirochromenes,
spiropyrans, polybithiophenes, leucodyes,
di-.beta.-napthospiropyrans, and other intrinsic color change
agents, can be used alone or in combination. Combinations of these
chromic change agents can be accomplished by either co-mixing
different agents homogeneously or selectively placing the different
chromic agents in zones so that each agent can be triggered by its
designated triggering method.
[0139] A variety of optical effects and applications can be
envisioned by using multiple chromic change agents either
specifically patterned or coprocessed. For example, a series of
chromic change agents can be patterned by a dot matrix or offset
printing process such that the zones or images of one type of
chromic agent can be visualized at ambient temperatures or
conditions. When the ambient temperatures or conditions are
altered, such as processes including cooking, heating, food
preparation, eating or digestion, the patterns change in response
to particular triggering mechanisms. The chromic change patterns
can be specified or preprogrammed to achieve particular memory
effects that can be entertaining and/or informative. Entertaining
pattern changes find use in promotional applications such as a
color change process that leads the consumer stepwise through food
purchasing, preparation and consumption. Multipart color images or
patterns and/or conditions which change in a complex or intricate
manner may necessitate the use of multiple chromic change agents.
Patterns that appear on ingestibles due to the response of chromic
change agents include text, characters, images, symbols, branding
identities, messages, icons, logos, artistic designs or decorative
designs.
[0140] Complex color patterns comprising multiple chromic change
agents may be used to communicate directions or recipes to a
potential or actual consumer. By way of example, a prepackaged food
item may incorporate a message on the item that suggests that the
item be purchased. After the package is opened, exposure to air,
light or room temperature may cause the disappearance of the first
message and a second message such as "Now add substance A" to be
displayed. Addition of substance A may induce a chemical change
that leads to a chromic agent-induced pattern change and the next
message, which may state, for example, "Now bake at 350.degree.
F.", "Add substance B", or the like. In addition to text-based
messages, an ingestible may be imprinted with a series of graphical
or "universal" displays that direct the consumer to the next step.
Examples of ingestibles that communicate directions may include
food items, pharmaceuticals or pills, or disposable swabs or other
devices that require some degree of preparation by the preparer or
consumer.
[0141] Complex information pattern changes also find use in
diagnostics and sensing applications where the pattern change
results when an ingestible is consumed, digested and excreted, as
described below.
[0142] Chromic change agents as diagnostic indicators: Intrinsic
color change agents that are irreversible in color change can be
used when it is important to preserve permanently or record a
physiological process. Intrinsic color change agents that are
reversible in color change can be used when it is important to
record repeatedly a physiological event and/or be able to trigger
reversibly a chromic change agent to confirm how it was originally
recorded as a diagnostic mechanism.
[0143] The chromic change and substance release system can find use
in various ingestibles where it is desirable to indicate to an
individual or health care worker that a drug, nutrient,
over-the-counter medicine or the like has been appropriately
released into the individual's digestive system. For example, a
chewing gum or similar product that is retained in the mouth rather
than swallowed, and that contains a chromic change agent combined
with a drug for delivery by chewing, can change color due the
sheering forces of chewing or from reaction with salivary chemicals
or enzymes. The chromic transition and corresponding color change
serves as an indicator to the individual that the substance has
been fully released from the gum and that further chewing is no
longer necessary in order to obtain the full effect of the
substance.
[0144] A chromic change agent may be incorporated on an diagnostic
ingestible, such as a throat lozenge, which indicates the presence
of a pathogenic microorganism. Streptococcus pyogenes, the
causative agent of streptococcal sore throat, is one such
microorganism that may be detected by this means. A chromic change
agent may be associated with one of a binding pair such as an
antibody, enzyme substrate, receptor ligand, etc., that interacts
directly or indirectly with the microorganism or its products. For
example, a chromic change agent may be incorporated in the lozenge
in a liposome or other lipid-based composition that is modified by
a lecithinase from the bacterium. A chromic change agent that
interacts when it contacts salivary components or other bacterial
metabolic processes or products could then change color upon
release from the liposome. Alternatively, a chromic change agent
may be linked to one of a binding pair, and interaction with the
other binding pair member causes a chemical change in the
environment of the chromic change agent and a subsequent color
change. An example would be a chromic change agent bound to an
enzyme substrate, wherein the substrate is specific for a
particular microbial enzyme. The substrate alters the pH or redox
potential in the environment of the chromic agent when acted upon
by the microbial enzyme, inducing a color change as a result of a
change in, for example, the ionization or redox potential of the
chromic agent.
[0145] A diagnostic color change ingestible can be used by the
medical community to evaluate a number of digestive tract disorders
or bodily dysfunctions in vivo. Devices can be constructed with
color change agents in selective patterns alone or in combination
where they are placed on a carrier such as a pill-sized bead or the
like, and then consumed. As the carrier is ingested and travels
through the digestive tract, it encounters various points at which
it can be triggered, and its color changes in a particular
color-changing zone. As the digestive process continues, the
carrier can record the wellness or dysfunctional state of the
digestive process. As the carrier is excreted during a bowel
movement it has a record of information of the digestive process
and can be used to give the consumer or physician general or
specific information about the digestive functionality in vivo. In
order to facilitate recovery and separation of the diagnostic color
change ingestible from fecal matter, a separation means can be
incorporated into the ingestible, such as, for example, a magnetic
core.
[0146] Ingestibles incorporating chromic change agents may also
find use as a detection method for bodily dysfunction such as
ketosis or liver dysfunction resulting in the lack of ability to
properly metabolize certain food components. The resulting
biochemical by-product in breath or saliva can act as a trigger for
a color change in the chromic agent, the change indicating the
presence of a bodily dysfunction. The chromic change agent can be
incorporated into a mouth wash, a gargle, a spray, or other
convenient form that enables saliva or breath to come in contact
with the chromic change agent and trigger a color change as an
indication of a dysfunction.
EXAMPLES
[0147] Specific foods or other compositions that are taken orally
that have been or can be used with the subject invention, as
illustrative of ingestibles generally.
Kellogg's Pop-tarts
Nabisco Cream of Wheat
Marshmallows
Kellogg's Rice Crispy Treats
Easy Bake Oven Products
Karo Syrup
Kellogg's Fruit Loops
Kraft Foods Jell-O
Hormel Franks Bologna
Pepperidge Farm Goldfish Soup Crackers
Nabisco Newtons
Flintstone Vitamins
Tums Antacid
Crest Toothpaste
Listerine Mouthwash
[0148] Throat lozenges French toast sticks Burger King Cinnamon
Buns Pillsbury frosting Cinnamon Minis--Special dip
frosting--Burger King
Example 1
Synthesis of Chromic Agents
[0149] Synthesis of N-ethanol-hexadeca-5,7-diyneamide: 1 molar
equivalent 5,7-hexadecadiynoic acid (GFS Chemicals) was dissolved
in dichloromethane to a concentration of 100 mg/ml and stirred at
room temperature. 1.05 equivalents of 1,1-dicyclohexyl carbodiimide
(DCC) were added and the mixture stirred. An immediate white
crystalline precipitate formed indicating the presence of
dicyclohexyl urea (DCU). The reaction mixture was stirred for 1
hour at room temperature. Ethanolamine (99.5% pure, Aldrich
Chemicals) was added drop wise to the unfiltered stirring solution.
The amide formation was checked periodically using TLC and spotting
a filter paper then ultraviolet 254 polymerization and testing
reversible thermochromism (85.degree. F. red/60.degree. F. blue).
The reaction was complete within 1 hour and left standing for a
total of 4 hours at room temperature. The DCU was filtered from the
reaction mixture using gravity filtration (Whatman 541) and allowed
to stand at 4.degree. F. over night. Additional DCU crystals formed
over night and were filtered using gravity filtration (Whatman
541). The solvent and residual ethanolamine was remove using a
Rotovap. The reaction product was resuspended in dichloromethane
and refiltered using gravity filtration (Whatman 541). The solvent
was removed a second time using a Rotovap. The reaction product was
suspended in hexane/dichloromethane solution (20/1 volume/volume).
The suspension was warmed to near the boiling point of the solvent
mixture to dissolve the product. The reaction crystallization
mixture was kept at room temperature for 6 hours. The crystallized
product was filtered using gravity filtration (Whatman 541),
redissolved and recrystallized a second time.
[0150] N-ethanol-hexadeca-5,7-diyneamide can also be prepared by an
alternate synthetic route whereby the 5,7-Hexadecadlynoic acid can
be converted to an acid chloride and added directly to a stirring
solution containing ethanolamine to yield the final amide product.
This route has the advantage of more direct purification since it
eliminates the need to remove a coupling agent such as residual DCC
or the DCU byproduct.
[0151] Synthesis of methyl 10,12-pentacosadiynoate (MePDA):
10,12-pentacosadiynoic acid (10 gm., GFS Chemicals) was dissolved
in a solution containing 10 ml methanol (HPLC grade) and 10 ml
chloroform (HPLC grade). The solution was stirred at room
temperature and 10 drops of neat sulfuric acid was added drop wise.
The solution was warmed to 100.degree. F. for 2 hour. The reaction
mixture was purified using column chromatography. The product
(MePDA) was dried using a Rotovap and the material stored in a
chloroform solution. The solid form of MePDA was very unstable to
polymerization and therefore kept dissolved in organic
solutions.
[0152] Synthesis of methyl 10,12-tricosadiynoate (MeTDA):
10,12-tricosadiynoic acid (10 gm., GFS Chemicals) was dissolved in
a solution containing 10 ml methanol (HPLC grade) and 10 ml
chloroform (HPLC grade). The solution was stirred at room
temperature and 10 drops of neat sulfuric acid was added drop wise.
The solution was warmed to 100.degree. F. for 2 hour. The reaction
mixture was purified using column chromatography. The product
(MeTDA) was dried using a Rotovap and the material stored in a
chloroform solution. The solid form of MeTDA was very unstable to
polymerization and therefore kept dissolved in organic solutions.
Alcoholic solutions of MePDA and MeTDA: Solids MePDA or MeTDA were
dissolved in reagent grade ethanol to a concentration of 150 mg/ml.
A residual polymer was removed by filtration through Whatman No. 1
filter paper. The solutions were held at room temperature or
slightly above (70-75.degree. F.) to avoid crystallization or
precipitation.
[0153] Synthesis of dimethyl his (10,12-pentacosadiynl oxyethyl)
ammonium chloride (BRONCO): 10,12-Pentacosadiynoic acid (5 gm. 13.4
mmol., GFS Chemicals) was dissolved in 60 ml dichloromethane and
filtered (Whatman No. 1) resulting in a colorless solution.
1,3-Dicyclohexylcarbodiimide (3.6 gm, 17.5 mmol., Aldrich Chemical
Corp.) and the base 4-dimethylaminopyridine (one equivalent,
Aldrich Chemical Corp.) were added to the solution and stirred for
15-20 minutes during which time a white crystalline precipitate,
dicyclohexylurea, formed. Bis(2-hydroxyethyl)dimethylammonium
chloride (1.14 gm., 6.68 mmol., Acros Organics-Fisher Scientific)
was added to the reaction mixture and stirred over night in a dry
inert atmosphere (nitrogen). The urea precipitate was filtered out
using (Whatman No. 1) and the reaction mixture was purified using
column chromatography. Dimethyl bis(10,12-pentacosadiynl
oxyethyl)ammonium chloride, Bronco, was dried using Rotovap and
stored in a powder form.
[0154] Alcoholic Monomer Solution of TDA/PDA: 10,12-Tricosadiynoic
acid (TDA, 6 gm GFS Chemicals) and 10,12-pentacosadiynoic acid
(PDA, 0.9 gm GFS Chemicals) were dissolved in 60 ml ethanol
(Fisher). The solution was slightly warmed and stirred. The
solution (TDA/PDA) was filtered (Whatman No. 1) to remove residual
polymer. Dye colorant could be added to the alcoholic monomer
solution as an indicator. Standard organic solvent based dyes were
added at 2 drops per ml.
Example 2
Preparation of Edible Printed Laminates
[0155] Ink Jet Printing: Black ink jet cartridges (Hewlett Packard
680C compatible or Cannon BJC2000) were modified to contain either
the TDAIPDA or MePDA alcoholic monomer solutions. The cartridges
were opened and the water based ink removed. The cartridges were
flushed with ethanol and the alcoholic monomer solutions added
separately to each cartridge. The cartridges were sealed, purged,
and inserted into an ink jet printer (Hewlett Packard 680C or Canon
BJC2000). Standard word processing and graphics programs were
utilized for printing. The ink jet cartridges were cleaned
periodically to remove residual build up of monomer caused by
drying.
[0156] Ink Jet Printed Thermochromic Sugar Laminates: Edible
laminates for ink jet printing (Kopykake, Torrance, Calif.) were
printed using the TDA/PDA or MePDA monomer solutions, food grade
ink jet dyes, and the ink jet printing systems described above.
[0157] Air Brush Coating Surfaces: Alcoholic solutions contain TDA,
PDA, TDA/PDA mixtures, or MePDA or an aqueous solution containing
BRONCO were prepared according to the methods described above and
sprayed onto food surface using a standard hand held air brush
Badger model 200, USA). Solutions were thinned or concentrated with
their corresponding solvent to achieve desired coating. Coating was
accomplished by applying a steady stream of vaporized material to
the surface at a distance of 1-6 inches. Patterns were formed using
paper stencils or by careful hand movement. After coatings were
applied and allowed to dry, the surfaces were polymerized using a
hand held ultraviolet lamp (254 nm).
Example 3
Temperature Triggered Chromic Change Agents
1. Temperature Indicating Ingestibles
[0158] 130-150.degree. F. Thermochromic Corn Syrup: Temperature
indicating syrup for hot pancakes, waffles, or the like were made
using a microcrystalline suspension of a polymeric polydiacetylene.
2 gm 10,12-tricosadiynoic acid was mixed with 45 ml corn syrup
(Karo brand Best Foods, Englewood Cliffs, N.J.) and then probe
sonicated at 40% power using a 400 watt sonicator (Cole Parmer
Instruments, Vernon Hills, Ill.) for 5 minutes. The sample heated
to about 140.degree. F. during sonication. After uniform mixing,
the sample was allowed to cool to room temperature (3 hours). A
white cloudy suspension appeared within 1 hour. The sample was
mixed using a stir rod until a creamy consistency resulted. The
sample was polymerized to a deep dark blue color in a shallow
plastic container using a hand held ultraviolet lamp (254 nm, Cole
Parmer Instruments, Vernon Hills, Ill.). The sample was irradiated
for 4 minutes and mixed using a stir rod.
[0159] The dark blue syrup was immediately available for use with
hot foods. The syrup could easily be spread on hot toast or
waffles. Upon application to the food, the dark blue syrup turned
bright red in color indicating the surface temperature of the hot
food it was applied to. The thermochromic transition temperature
occurred at between 130.degree. F. to 150.degree. F.
[0160] 110-130.degree. F. Thermochromic Corn Syrup: Moderate
temperature triggering corn syrup was made using the formulation
described above and by adding absolute ethanol at 5% by volume. The
ethanol was added to a premixed unpolymerized suspension. The
suspension and ethanol were mixed to uniformity for 5 minutes at
room temperature and polymerized using the identical conditions
described above. The thermochromic transition temperature of the
polymerized mixture occurred at between 110.degree. F. to
130.degree. F.
[0161] Temperature Indicating Thermochromic Icing/Syrup: 5 ml of
the MePDA alcohol solution (above) and 10 gm cake icing (Signature
Brands, LLC, Ocala, Fla.) were uniformly mixed at room temperature
for 10 minutes. Most of the ethanol from the solution evaporated.
The resulting creamy paste was chilled to below freezing
(-10.degree. F.) and then exposed to an ultraviolet lamp (hand
held, 254 nm) for 5-10 minutes while remaining chilled. The mixture
was churned during exposure to give a uniform blue appearance. The
thermochromic icing was temperature triggered by simply raising it
above freezing (greater than 50.degree. F.). The icing immediately
turned bright red when applied to surfaces exposed to room
temperature, directly exposed to room temperature, or touched by
directly by hand. Oils contained within the icing helped to
facilitate the temperature triggering of the thermochromic agent in
the icing. Partially hydrogenated vegetable oils (soybean and
cottonseed) are solid in nature at freezing temperatures, keeping
the blue polymeric MePDA stable. As the oils melt at above room
temperature, the polymeric MePDA is subsequently influenced to
transition from a dark blue color to a bright red. The icing was
further packaged in air sealed plastic pouches (4 mil,
polyethylene) and heat-sealed using a conventional heat sealer.
Care was taken not to expose or contact the dark blue frosting to
temperatures above freezing. The frosting/syrup could conveniently
be extruded onto a pastry surface. During the application, the dark
blue color turned immediately bright red due to finger contact with
the pouch and exposure to a room temperature surface.
[0162] Low Temperature Indicating Marshmallows: Marshmallows were
quickly dip coated into the MePDA alcohol solution and allowed to
dry at room temperature or below. The monomer dip coated
marshmallows were exposed to ultraviolet light (hand held lamp, 254
nm) and rotated for uniform polymerization (approximately 2
minutes) until they became dark blue. The marshmallows were stable
at room temperature or below (68.degree. F.). They immediately
changed to a bright red/orange color upon direct touching, contact
with warm fluids, or placing in the presence of an open flame
(95.degree. F. or above).
[0163] High Temperature-indicating Hot Chocolate: Yellow dye number
6, red dye number 40, and a medium blue polydiacetylenic
thermochromic agent that turns orange when triggered by heating
were added to a hot chocolate mix prepared at room temperature. The
resulting combination of hot chocolate, dyes and thermochromic
agent was brown in color. When hot water was added to the solution,
the brown color changed to a combination of yellow and red,
bringing the brown mix to a bright orange color.
2. Cooking State-Indicating Ingestibles
[0164] Temperature Indicating Frozen Waffles: Frozen waffles (Eggo
brand, Kellogg Company) were removed from their package and
immediately sprayed with an alcohol based monomer solution (above).
Waffles were coated at 68.degree. F. using a standard airbrush.
Patterns were created using the square cells on each waffle. The
monomer solution dried immediately on the waffle surface. The
monomer-coated waffles were polymerized using a hand held
ultraviolet lamp (254 nm, 6 inches for 10 to 60 seconds). Radial
polymerization gradients were used to increase the level of
polymerization from the outer region of the waffle to the center.
Increasing the level of polymerization causes a corresponding
increase in the final colorimetric temperature transition of the
thermochromic agent. The resulting waffles had a dark blue
appearance upon polymerization. The patterned thermochromic
indicating waffles were conveniently re-stored in the freezer prior
to use. The temperature indicating waffles were toasted using
normal instructions on the package. As the waffles were heated, the
dark blue color changed to a bright red/orange. The outer portions
of dark blue changed color first. As heating continued, the inner
portions of blue at the center of the waffles turned color to
red/orange last. The color transition was complete when the waffles
were fully heated indicating that toasting was complete and the
waffles ready to serve.
[0165] Ground meat patty possessing a chromic change agent particle
for indicating internal safe cooking temperatures: Chromic change
particles were prepared by coating sesame seeds with a thin layer
of a chromic change agent. An ethanol solution was prepared with
ethanol (Spectrum Chemicals, Inc.) containing 150 mg/ml
10,12-tricosadiynoic acid and 15 mg/ml 10,12 pentacosadiynoic acid.
The solution was warmed to 100.degree. F. to dissolve all of the
diacetylenic acid. 10 gm sesame seeds were placed in a screw cap
vial and saturated with 2 ml of ethanolic solution. The seeds and
solution were shaken and tumbled for 3 minutes to ensure complete
coverage of each seed. The seeds were poured into a Teflon coated
dish and tumbled for 10 minutes with a gentle air stream to ensure
that all of the ethanol solution was removed. The coated particles
were vigorously shaken and exposed to ultraviolet light (hand held
lamp, Cole Parmer, Inc. 254 nm) for 5 minutes resulting in the deep
blue appearance of the polydiacetylenic polymer. The coated
particles were stored overnight at room temperature.
[0166] The blue polymer coated particles were admixed with ground
hamburger meat to a concentration where multiple particles were
present in the central region of a patty each time a patty was
sliced through Patties was grilled on a gas grill and flipped over
during cooking. The center of patties were systematically tested
during grilling to determine the extent of color change during
cooking. Color change particles toward the outer segments of a
patty turned color to a bright red/orange earliest during cooking.
Color change particles in the center of a burger turned color to a
bright red/orange once the burger's internal temperature achieved
160.degree. F. indicating that the burger was cooked
thoroughly.
[0167] Baby Food The likelihood that a child will be burned by
ingesting overly-heated baby food solids and liquids may be
significantly reduced by using a color reversible thermochromic
agent combined with a food or formula. Solid foods or formulae may
be prepared with a blue thermochromic agent. Upon heating the food
or formula the thermochromic agent changes color to orange,
indicating a high temperature, which then reverts to the blue color
when the temperature of the food or formula is safe to ingest. The
thermochromic agent can also be used to indicate uneven temperature
distribution in various regions of the food or formula, and that
the food should be mixed to achieve a more uniform, safe
temperature.
[0168] Thermochromic Graphically Patterned PopTarts: PopTarts
(Kellogg Company) were coated with a commercially available sugar
glaze and allowed to dry for several hours at room temperature.
Edible laminates jet printed (Kopykake, Torrance, Calif.) with
either TDAIPDA or MePDA monomer solutions and the Kopyjet ink jet
printing system as described above were applied to the glazed
PopTart surface. Initially the glaze surfaces were slightly wetted
to facilitate the adherence of the edible laminate. Various
entertaining patterns were graphically rendered for application on
the PopTarts. The monomer printed surfaces were polymerized using a
hand held ultraviolet lamp (254 nm) at a distance of 3 inches for 5
to 10 seconds depending on the desired level of blue color. TDA/PDA
printed/polymerized PopTarts changed color from a dark blue to a
bright red/orange when exposed to toaster or microwave
temperatures. MePDA printed/polymerized PopTarts changed color from
a dark blue to a bright red/orange when exposed to finger touch or
above 90.degree. F.
[0169] Franks and Hot Dogs: Processed hot dogs can be impregnated
with a thermochromic material which turns color when a specific
heat is achieved. The material can be patterned such that lettering
may indicate the words "HOT DOG" for promotional and advertisement
value. Conveniently, an aqueous form of the thermochromic agent is
ink jet printed into a pattern representing words of interest. The
polymerizable dual chain lipid BRONCO was suspended in water and
pre-polymerize with ultraviolet light (254 nm) at room temperature
to a dark blue ink color. The polymer solution was printed on the
side of a retail available hot dog (Hormel or Kraft). The chromic
agent can also be printed on the meat product cellulosic casing
prior to filling the casing with processed meats and fillers.
Casings are typically extruded, processed, and dried prior to
filling. Printing on the unfilled casing provides the advantage of
printing on a dry solid surface using high speed printing and
drying methods with out effecting the foodstuff. Printing on the
casing can involve ink jet printing, pad printing, masking,
spraying, silk screening, extrusion or the like.
[0170] Brownie Mix: Brownie mixes were prepared by incorporating a
blue thermochromic agent that changes to bright orange upon
heating. Upon preparation of the brownie mix according to the
manufacturer's directions and baking, the dark brown mix became
bright orange. The thermochromic agent thus served as both an
entertaining color change component of the mix, and as an indicator
that the brownies were done and ready to be removed from the
oven.
[0171] Embedded food bar codes: Embedded thermochromic bar codes
produced directly on the side of a pre-baked ham cut. A
thermochromic bar code allows a standard bar code and bare code
reader to be used as a thermometer device. An alcoholic solution
containing TDAIPDA (described above) was sprayed locally on the
side of a 1 pound piece of pre-cooked ham (Hormel Company). The ham
surface was prepared by damp drying a 1.times.2 inch region. The
region was sprayed at a distance of 3 inches using an airbrush as
described above. An ultraviolet transmissive photomask with a
negative bar code pattern was prepared using a black film thermal
transfer printer (Brother) and 8.5.times.11 inch sheet of 4 mil
thick clear polyethylene sheet. The bar code photomask, sized to
0.75 by 1.5 inch, was placed directly over the sprayed region of
TDA/PDA. The bars in the code were transmissive to ultraviolet
light (254 nm). The bars were selectively exposed using a light
shield over certain bars while others were exposed. This method
allowed some bars to be polymerized for 100% more time than others
did so that the lesser exposed bars would change color at lower
temperatures (125.degree. F.) and the more highly exposed bars
would change color at higher temperatures (170.degree. F.). The
differential temperatures were set so that a bar code reader could
read while ham was hot so that the bar code scanner could interpret
the disappearance of certain bars (due to the dark blue to red
color transition during heating) as being a different code than
when it started. The scanner information was converted digitally
using a standard computer so that the corresponding computer output
could indicate the actual temperature.
3. Decoration of Ingestibles
[0172] Thermochromic cereals: A low temperature reversible
thermochrome can be prepared in a versatile polyethylene glycol
coating. A coating solution containing the polymerizable monomer
N-ethanol-hexadeca-5,7-diyneamide (100 mg/ml) 3,350 molecular
weight polyethylene glycol (750 mg/ml) was made in an ethanol
(absolute) by warming to 120.degree. F. and mixing. The viscous
solution remained clear above 100.degree. F. The coating solution
is slightly viscous and easily applied to a food surface by
blotting, painting, or spraying. Both the
N-ethanol-hexadeca-5,7-diyneamide and polyethylene glycol
crystallize from solution upon cooling to room temperature and
solvent evaporation. Foods cereals such as Kellogg's Frosted
Miniwheats were coated by painting with a thin coat and allowed to
dry at room temperature for 2 hours. The resulting coat dried to a
hard wax-like appearance. The N-ethanol-hexadeca-5,7-diyneamide was
polymerized using a hand-held ultraviolet lamp (254 nm, 6 inch
distance) for a total exposure time of 1 minute. The resulting
layer became strongly magenta at room temperature 68 72.degree.
F.), bright red/orange at increasing temperature (85-95.degree.
F.), and dark blue/purple when chilled (35-55.degree. F.). The
color change is completely reversible as long as the upper
temperature level is maintained below 130.degree. F. The coated
cereal pieces turn from a bright magenta/red to dark purple/blue
when cold milk is poured over their surface (42.degree. F.). The
dark purple/blue color remains as long as the milk remains cold.
The color is thermochromically reversible through hot and cold
cycles.
[0173] Processed thin sliced cheese: Pre-packaged thin sliced
cheese can be printed with the aqueous solution of the
thermochromic agent. The solution can be pre-polymerized or in a
monomeric form which can be polymerized after printing. The
thermochromic agent is absorbed to the cheese surface upon brief
drying causing a strong bonding to occur between the thermochromic
agent and the surface of the cheese.
[0174] A pattern of the American flag was produced on the surface
of a thin slice of American cheese (Kraft 2% Milk Reduced Fat Milk
Singles). The pattern was painted using a thin brush and a dark
blue solution of pre-polymerized BRONCO. The pattern was allowed to
dry at room temperature for 5 minutes and the cheese repackaged for
storage.
[0175] The flag-painted slice of cheese was placed on a hamburger
while the burger was cooking on a grill. Within 2-3 minutes, the
cheese began to melt. During heating and melting, the dark blue
flag pattern became bright red. The flag pattern also started to
flow and contort as the cheese melted and flowed. The flow process
gave rise to an interesting effect, simulating a waving and moving
flag.
[0176] Thermochromic sugars, salts, spices, cheese powders, grated
cheese, and shredded cheese: An ethanol coating solution was
prepared with ethanol (Spectrum Chemicals Inc.) containing 150
mg/ml 10,12-tricosadiynoic acid (GFS Chemicals, Inc.). The solution
was warmed to 100.degree. F. to dissolve all of the diacetylenic
acid. Twenty grams of sugar, salt, spice (e.g. paprika or mustard
seeds), or cheese powder (e.g. Parmesan cheese or powdered cheese
from Kraft Macaroni and Cheese mix) were added to a screw cap
bottle and saturated with up to 2.5 ml of the ethanolic solution. A
powder and solution were shaken and tumbled for 3 minutes to ensure
complete coverage of the particles. The solution wetted powders
were poured into a Teflon coated dish and tumbled for 10 minutes
with a gentle air stream to ensure that all of the ethanol solution
was removed. The coated powders were vigorously shaken and exposed
to ultraviolet light (hand held lamp, Cole Parmer, Inc. 254 nm) for
5 minutes resulting in the deep blue appearance of the
polydiacetylenic polymer. Once dry, the coated powders could be
used immediately.
[0177] Thermochromic triggering was accomplished by applying a
powder type directly to a heated food type. For example, the
chromic agent coated powder cheese was added to a pre-heated/cooked
bowl of macaroni. On contact, the dark blue cheese powder turns to
a vivid red orange color. Visual effects can be created by first
adding a small pile of the treated pile to a hot food. At first the
shallow edges turn orange and then the blue pile gradually turns
orange with the orange color radiating inward until finally the
peak is triggered orange. Alternatively, the coated powder can be
sparsely sprinkled on the food such that each grain turns color
instantly.
[0178] Thermochromic soup crackers: Soup crackers (e.g., Pepperidge
Farms Fish Cracker brand or standard soup crackers) were lightly
sprayed and wetted with an adhesive food glaze (150 mg/ml water
soluble starch dissolved in purified water sprayed with a
nebulizer). The lightly wetted surface was tacky to the touch for
several minutes prior to drying. While the surface was tacky, the
crackers were coated with a thermochromic salt powder as prepare
above. The coated salt particles adhered to the cracker surface
once the adhesive food glaze dried. The final crackers revealed a
blue tint, on their surface. The optical density of blue color was
regulated by the amount of coated salt applied.
[0179] Thermochromic triggering was accomplished by dipping a
cracker into a hot bowl of soup. The dark blue tint on the cracker
surface turned immediately to a bright orange on contact with the
hot liquid. Visual effects were created by dipping the crackers at
various depths and angles into the soup.
4. Storage Temperature Condition Indicators
[0180] Raw egg holding temperature indicator: Eggs were printed
with the alcoholic solution containing MeTDA described above. The
monomer solution was spot printed using a porous felt pad saturated
with the monomer solution. Printing was conducted while the eggs
were held at 40.degree. F. The monomer was allowed to dry for 2
minutes and polymerized at using a hand held ultraviolet lamp (254
nm) at 40.degree. F. The dark blue printed spot held its color on
an egg until the egg was raised to between 55 to 65.degree. F. were
the dark blue spot became bright red/orange indicate that the egg
was exposed to an excessive holding temperature range. Eggs should
be kept at refrigerator temperature during storage due to the
potential contamination of Salmonella and the possibility of cell
replication at above refrigerator temperatures.
Example 4
Mechanical Stress-Triggered Chromic Change Agents
[0181] Candies and cookies possessing mechanically induced color
changes: Hard candies such as jaw breakers, M & M's, hard
coated gum pieces, hard icing coated cookies, or the like were
coated with a color change agent that changes color due to
mechanical and/or frictional forces applied to the surface with the
mechanochromic agent. An ethanol coating solution was prepared with
ethanol (Spectrum Chemicals, Inc.) containing 200 mg/ml
10,12-octadecadlynoic acid (GFS Chemicals, Inc.). The solution was
spray coated onto candy or cookie surfaces using a conventional air
brush system. The coating can be applied either while the candy or
cookie surface is stationary or tumbling. Once an even coat has
been applied, the surfaces are allowed to dry at room temperature
of 30 minutes. The coated surfaces are polymerized using an
ultraviolet light (hand held lamp, Cole Parmer Inc. 254 nm) for 5
minutes resulting in the blue appearance of the polydiacetylenic
polymer.
[0182] Candy and cookie surfaces coated with the blue
polydiacetylene layer are changed to a red/orange color by rubbing
surfaces together, rubbing with a finger or finger nail, or rubbing
with a compatible hard surface. Surfaces with temperature
insulative properties such as finger nails, napkins, wood sticks,
paper dowels, plastic sticks or the like are superior for inducing
the color change compared with metal or glass surfaces which have
heat conductive surfaces. Patterns, messages, and graphical images
can be created on the mechanochromic surface by localized rubbing
without changing the color of an adjacent region of the blue
mechanochromic agent.
[0183] Mechanochromic tooth paste: A ratio of 10 g Crest Tooth
Paste with 1 gram pre-polymerize flakes of 5,7-hexadecadiynoic was
mixed at room temperature to become a blue paste containing small
blue particles of the diacetylenic polymer. 5,7-hexadecadiynoic
acid (GFS Chemicals, Inc.) flake-like crystals were polymerized to
a dark blue tint using a hand-held ultraviolet lamp (Cole Parmer
inc.) for 3 minutes. The flakes were agitated during the process to
ensure complete polymerization. The dark blue flakes were added to
tooth paste at room temperature and mixed thoroughly. The final
formulation was stable at room temperature. The mechanochromic
tooth paste turned form a dark blue paste to a pink/purple color
when the tooth paste was abraded back and forth with a standard
tooth brush (medium bristles) for 2-3 minutes.
[0184] Touch Sensitive Rice Krispie.RTM. Treats: Retail Rice
Krispie Treats (Kellogg Company) were air brush spray coated using
the method described above and an alcoholic solution of MePDA
prepared as described above. The Rice Krispie Treats surfaces were
inclined at 30 degrees on an open tray and sprayed at a distance of
4 inches using a moderate stream flow from the airbrush. The
coatings were allowed to dry for 5 minutes at 65 g. Pattern coating
was accomplished using an open letter stencil and spraying just
beyond the outline of the stencil. Polymerization was accomplished
using a hand held ultraviolet lamp (254 nm) moved back and forth
over the surface for 5 seconds at a distance of 3 inches. The
surface immediately became dark blue and could be made to change
color to a bright red/orange by finger touch, breathing on the
surface, or biting into the surface.
Example 5
Combined Temperature-Mechanical Stress-Triggered Chromic Change
Agents
[0185] Combined photochromic thermochromic-mechanochromic cookies:
An ethanol solution was prepared with ethanol (Spectrum Chemicals,
Inc.) containing 150 mg/ml 10,12-tricosadiynoic acid and 15 mg/ml
10,12-pentacosadiynoic acid. The solution was warmed to 100.degree.
F. to dissolve all of the diacetylenic acid. The solution was
loaded into an emptied, cleaned, and dried ink jet cartridge
(Hewlett Packard HP 51629A). The cartridge was placed in an ink jet
printer (Hewlett Packard, Deskwriter 680C). The printing room and
printing components were maintained at a temperature of 95.degree.
F. to ensure that the ethanol printing solution remained soluble.
Edible laminates Kopykake Inc., Torrance, Calif.) were printed
using standard graphics programs and interfaces.
[0186] Graphical images were printed on the laminate and then
adhered to the surface of cookies. The cookies were place in the
sun or exposed to a hand held ultraviolet light source (Cole
Parmer, Inc.). The graphical images appeared exactly as they were
printed upon exposure. The graphical images became visible within
minutes in sun light (peak intensity at 12:00 noon during the
spring time in California). The color became progressively darker
with continued exposure up to hours.
[0187] The dark blue images printed on the cookies could be
subsequently triggered to a bright red upon heating the cookie or
dipping it in hot liquid (milk heated to 130.degree. F.).
Variations ultraviolet activated color development times and
thermochromic temperature transitions can be achieved by modifying
the polydiacetylene structure utilized.
[0188] The blue polydiacetylenic images on the cookie surface can
also undergo a mechanochromic transition to a red/orange color by
mildly rubbing the image/cookie surface. The mechanochromic effect
is highly localized to the specific are being contacted. The image
can be graphically altered by localized rubbing to achieve
different graphical effects based on multiple colors (e.g. the
background cookie color, the blue form of the polymer, and the
red/orange form of the polymer).
Example 6
Combined Temperature-Chemical Triggered Chromic Change Agents
[0189] Chromic change liquid beverage with dual function: An
aqueous suspension 100 mg/ml of N-ethanol-hexadeca-5,7-diyneamide
was prepared using ultrasonication and lecithin as an emulsifier.
One gram N-ethanol-hexadeca-5,7-diyneamide (prepared as described
in this patent) and 1 gram egg lecithin (Sigma Chemicals, Inc.)
were added to a glass beaker along with 30 ml filtered water and
sonicated with a high power probe sonicator (Cole Parmer, Inc.) for
10 minutes at 130.degree. F. Homogeneous suspension formation
required agitation and mixing. The final suspension was milky
white. The suspension was allowed to cool to room temperature and
left to stand 24 hours. The suspension was dispersed by mixing or
agitation. Five ml of the solution was added to a shallow dish and
exposed to ultraviolet light (hand held lamp, Cole Parmer, Inc. 254
nm) for 5 minutes (with continual mixing and agitation) resulting
in the deep magenta appearance of the polydiacetylenic polymer
(room temperature). The magenta color chromic solution could be
diluted with water or kept concentrated.
[0190] For thermochromic conversion, a 5 fold diluted solution of
the chromic solution (purified water) was poured over crushed ice
in a clear glass. The color immediately changed to a dark
purple/blue color upon chilling. The solution color was
thermochromically reversible when rewarmed to room temperature and
subsequently chilled back to near freezing temperatures.
Temperature cycling could be repeated numerous times.
[0191] For chemochromic conversion the chilled purple/blue chromic
solution can be further changed to a bright pink/orange color by
the addition of alcohol (chilled or ambient in temperature).
Addition of an increasing concentration of alcohol caused the
purple/blue color to progressively turn irreversibly to a
pink/orange color. When greater than 50% alcohol (volume/volume
water/alcohol) is added the solution becomes completely
pink/orange. The system serves as a means to detect the presence of
polar solvents such as alcohol or acetone.
Example 7
[0192] Moisture Triggered Chromic Change Agents
[0193] Hydrochromic ingestible sugar, sprinkles, nonpareil and salt
powders: An ethanol coating solution was prepared with ethanol
(Spectrum Chemicals, Inc.) containing 130 mg/ml
4,6-decadiyne-1,10-diol (GFS Chemicals, inc.). 20 grams sugar or
salt powder were added to a screw cap bottle and saturated with up
to 2.5 ml of the ethanolic solution. A powder and solution were
shaken and tumbled for 5 minutes to ensure complete coverage of the
particles. The solution wetted powders were poured into a Teflon
coated dish and tumbled for 10 minutes with a gentle air stream to
ensure that all of the ethanol solution was removed and the coated
powder consisted of a in a fine grain mesh with out clumps. The
coated powders were vigorously shaken and exposed to ultraviolet
light (hand held lamp, Cole. Parmer, inc. 254 nm) for 5 minutes
resulting in the deep blue/purple appearance of the
polydiacetylenic polymer. Once polymerized the coated powders could
be used immediately. Hydrochromic powders were stored at room
temperature of below in sealed jars and desiccants.
[0194] Hydrochromic powders were adhered to food surfaces such as
cereals, cookies, crackers or any other food type intended to come
in contact with an aqueous medium. For example, a hydrochromic
sugar can be coated on the surface of a cookie intended of dipping
in milk. The visual appearance of the blue/purple sugar powder can
be enhanced by pre-coating the cookie with a bright white royal
hard sugar icing. Immediately prior to the final drying stage of
icing, a hydrochromic sugar powder can be layered on to the icing
surface. Residual water in the cookie icing will not change the
outward surface color of the hydrochromic sugar powder as long as
the water content in the icing is minimized and the grains do not
wet. A gentle air stream over the coating facilitates drying.
Alternatively a tacky adhering glaze can be used for coating the
food surface with the powder. The blue/purple powder can be coated
at a density practical for viewing.
[0195] Hydrochromic triggering is accomplished by dipping a coated
cookie into chilled milk (liquid at room temperature or as low as
45.degree. F.). The blue/purple color changes to a bright orange on
wetting. The color change within seconds using liquids at near room
temperature and has a delayed effect over 30 to 90 seconds using
liquids well below room temperature (45.degree. F. to 55.degree.
F.).
[0196] Powders with very thin coats of the hydrochromic agent
change color more rapidly than coatings that are thick since
thicker coatings are restrictive in letting water rapidly
intercalate into the chromic agent's interstitial layer. The visual
effect of hydrochromic color change can be regulated depending on
the food type of interest. Hydrochromic coatings can also find use
as integrated indicators that foods have been properly sealed form
moisture there by ensuring freshness and dryness during
storage.
[0197] It is evident from the above description and results that by
using a thermochromic agent that undergoes a color change, many
applications accrue. The thermochromic agent may be applied to a
wide variety of ingestibles in a wide variety of manners,
incorporated into the ingestible, particularly liquids, or
associated with the ingestible, such as on packaging materials. The
thermochromic composition can be used to ensure that an ingestible
has been stored safely, that it has been cooked to a desirable
temperature, that it has cooled to a desired temperature, or solely
for marketing or entertainment purposes. Exposure of ingestibles
comprising moisture-sensitive chromic change agents to solutions or
moist atmospheres can provide entertaining color changes or reveal
text or imaged based messages. Mechanical stress-triggered chromic
change agents that change color due to mechanical and/or frictional
force may be incorporated into a variety of ingestibles that are
rubbed, scratched, chewed, compressed, or the like, and find
particular use in toothpastes and touch-sensitive ingestibles.
Ingestibles incorporating a number of different chromic change
agent combinations are provided that can reveal different text
messages or images and sequentially-displayed text or images based
on the types of treatments to which the ingestible is exposed.
These messages may serve to direct the user to the next step in a
preparation process, reveal hidden messages, and serve as
diagnostic indicators. The compositions are physiologically safe
and may be modified to be appropriate as to a particular
temperature transition and compatible with the ingestible.
[0198] All publications and patent applications mentioned in this
specification are herein incorporated by reference to the same
extent as if each individual publication or patent application was
specifically and individually indicated to be incorporated by
reference.
[0199] The invention now being fully described, it will be apparent
to one of ordinary skill in the art that many changes and
modifications can be made thereto without departing from the spirit
or scope of the appended claims.
* * * * *