U.S. patent application number 11/498325 was filed with the patent office on 2007-08-09 for methods and apparatus for removal of degradation byproducts and contaminants from food grade oil.
This patent application is currently assigned to DuraFizz, LLC. Invention is credited to Michael C. Berg, William M. Mowers, David Soane.
Application Number | 20070184158 11/498325 |
Document ID | / |
Family ID | 37398877 |
Filed Date | 2007-08-09 |
United States Patent
Application |
20070184158 |
Kind Code |
A1 |
Soane; David ; et
al. |
August 9, 2007 |
Methods and apparatus for removal of degradation byproducts and
contaminants from food grade oil
Abstract
Methods, particles and devices are disclosed which are suitable
for food-grade oil filtration. Disclosed particles may comprise an
inert porous inner particle and at least a partial coating on the
inner particle that comprises a polymer comprising at least one
amine, amino or imine group.
Inventors: |
Soane; David; (Chestnut
Hill, MA) ; Berg; Michael C.; (Somerville, MA)
; Mowers; William M.; (Lynn, MA) |
Correspondence
Address: |
ELMORE PATENT LAW GROUP, PC
209 MAIN STREET
N. CHELMSFORD
MA
01863
US
|
Assignee: |
DuraFizz, LLC
Cambridge
MA
|
Family ID: |
37398877 |
Appl. No.: |
11/498325 |
Filed: |
August 2, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60704697 |
Aug 2, 2005 |
|
|
|
Current U.S.
Class: |
426/417 |
Current CPC
Class: |
B01J 20/3217 20130101;
C11B 3/008 20130101; B01J 20/28004 20130101; B01J 20/3293 20130101;
B01J 20/14 20130101; B01J 20/3236 20130101; Y02E 50/13 20130101;
C10L 1/026 20130101; B01J 20/327 20130101; B01J 20/3282 20130101;
B01J 20/3272 20130101; B01J 20/28054 20130101; B01J 20/28016
20130101; Y02E 50/10 20130101; B01J 20/328 20130101; C11C 1/08
20130101; B01J 20/26 20130101; B01J 20/3268 20130101; C11B 3/10
20130101 |
Class at
Publication: |
426/417 |
International
Class: |
A23C 15/14 20060101
A23C015/14 |
Claims
1. A method for filtering contaminated edible oil comprising the
step of contacting said edible oil with a filtering media
acceptable for food-grade use, wherein said filtering media
comprises a polymer comprising an amine group, an imine group, or
both.
2. The method of claim 1, wherein said polymer comprises a primary
amine group.
3. The method of claim 1, wherein said polymer comprises a
secondary amine group.
4. The method of claim 1, wherein said filtering media comprises a
plurality of particles.
5. The method of claim 4, wherein said particles are at least
partially coated with said polymer.
6. The method of claim 5, wherein said particles have an average
diameter of about 1 to about 10 microns.
7. The method of claim 1, wherein said polymer comprises a
positively charged amine group, a positively charged imine group,
or both.
8. The method of claim 7, wherein said polymer is an amine
salt.
9. The method of claim 2, wherein said primary amine has a positive
charge created by contact of said polymer with an acid.
10. The method of claim 9, wherein said acid is hydrochloric
acid.
11. The method of claim 8, wherein said polymer is a hydrochloric
acid salt.
12. The method of claim 1, wherein said polymer is
cross-linked.
13. The method of claim 5, wherein said particles are porous.
14. The method of claim 1, wherein said method filters contaminants
in said oil by attraction of said contaminants to said polymer,
wherein said contaminants comprise at least two of the following
types: polymerized oils, fatty acids, metals, and polar
contaminants.
15. The method of claim 5, wherein said particles comprise
diatomaceous earth.
16. The method of claim 1, wherein said polymer comprises
chitosan.
17. The method of claim 5, wherein said polymer comprises
chitosan.
18. The method of claim 17, wherein at least one primary amine of
the chitosan is positively charged.
19. A particle suitable for food-grade oil filtration comprising a
substantially inert porous inner particle and at least a partial
coating on said inner particle, wherein said coating comprises a
polymer comprising an amine group, an amino group, an imine group,
or a combination thereof.
20. The particle of claim 19, wherein said polymer comprises a
primary amine group.
21. The particle of claim 19, wherein said polymer comprises a
secondary amine group.
22. The particle of claim 19, wherein said polymer comprises a
positively charged amine group.
23. The particle of claim 19, wherein said polymer is in the form
of an amine salt.
24. The particle of claim 19, wherein said polymer is cross-linked
so that said coating is substantially porous.
25. The particle of claim 19, wherein said coating has a thickness
of about 1 micron or less.
26. The particle of claim 19 wherein said inner particle comprises
diatomaceous earth.
27. The particle of claim 26 wherein said coating comprises
chitosan.
28. The particle of claim 23 wherein said polymer comprises
chitosan.
29. A filtration device comprising a plurality of particles,
wherein at least some of said particles comprise a polymer
acceptable for food use comprising at least one amine group.
30. The filtration device of claim 29, wherein said amine is
positively charged.
31. The method of claim 1, wherein said polymer comprises a
tertiary amine group.
Description
RELATED APPLICATIONS
[0001] This application claims benefit of U.S. Provisional Patent
Application No. 60/704,697, filed on Aug. 2, 2005, which is hereby
incorporated by reference in its entirety.
FIELD OF INVENTION
[0002] This invention relates generally to methods, particles and
devices suitable for food-grade oil filtration. Disclosed particles
may comprise a substantially inert porous particle with a coating
comprising a polymer having amine, amino, and/or imine
group(s).
BACKGROUND
[0003] Oils and fats are complex mixtures of water insoluble
organic compounds derived from animal or vegetable sources. Such
mixtures find utility in a variety of applications around the
world. Oils can have a range of properties due to their unique
compositions, which vary according to the sources from which they
are derived. Oils are particularly well-suited to applications such
as lubrication, heat transfer, and food preparation. For the food
industry, oils are chosen based on their potential health benefits
to the end user, their taste, and their physical properties.
[0004] The commercial utility of oils and fats is immense. Millions
of tons of oils and fats are used per annum in edible products,
including butter, margarine, lard, shortening, mayonnaise, salad
oil, and cooking oil. The major components found in cooking or
edible oils are primarily triglycerides, which are esters of
glycerol linked with three molecules of fatty acids. The fatty
acids contain a carboxyl group and a hydrocarbon chain. Individual
fatty acids are distinguished from one another by the nature of the
hydrocarbon chain, which can vary in length from about 4 to about
24 carbon atoms and can be saturated, monounsaturated (one double
bond), or polyunsaturated (two or more double bonds). The most
common fatty acids in edible oils and fats are those containing 18
carbons and those having one or more unsaturation (one or more
double bond).
[0005] These oils can be applied in a working environment where
high temperatures are maintained over prolonged periods of time
with contact to air. The exposure to high temperatures in the
presence of either oxygen or water can lead to degradation of the
compounds in the oil via processes such as oxidation and lipolysis.
These reactions lead to contaminants that result in an oil that
becomes visibly darker in color, has an increase in malodorous
components, and a less palatable flavor. This process of
degradation of the oil results in rancidity. As the oil becomes
rancid, the oil also begins to produce heavy smoke at normal
cooking temperature and becomes unusable.
[0006] Lipolysis is the decomposition of the ester linkage in the
fatty acid. This process is caused by water introduced to the
system from frozen foods, for example, or even from fresh foods.
The water reacts at the elevated temperatures with the fatty acids,
breaking apart the ester linkage to form an acid and an
alcohol.
[0007] Oxidation is due to the exposure of the oil to the oxygen
present in air. Oxygen reacts adversely with the double bonds in
the fatty acids. Oxygen is about five times more soluble in oil
than in water. Oxygen will react with cooking oil to form many
byproducts. These products include peroxides, aldehydes, ketones,
epoxides and acids, to name a few.
[0008] Oil may also pick up particulates and products from the
foodstuffs that are placed in the oil for cooking. These
contaminants also lead to the degradation and discoloration of the
cooking oil.
[0009] The combination of reaction byproducts and contamination
from cooking leads to another problem in deep frying, which is the
buildup of soap-like compounds. These soapy materials eventually
lead to undesirable foaming oil. This property is often used as an
indicator of the rancidity of the oil.
[0010] Another problem that is associated with these compounds is a
build up of trace metals in the oil, which give rise to unpalatable
flavors. Trace metals act as a catalyst for the reaction of oxygen
and the oil compounds. Thus, the presence of these compounds will
cause the oil to turn rancid at a much faster pace. Without
treatment, these decomposition processes occur rapidly and
ultimately will require the replacement of the cooking oil as often
as every 2 or 3 days, thereby significantly raising the cost of
operation of a commercial fryer.
[0011] Biodiesel is a fuel comprised of mono-alkyl esters of long
chain fatty acids derived from vegetable oils or animal fats.
Biodiesel is typically produced by a reaction of a vegetable oil or
animal fat with an alcohol such as methanol or ethanol in the
presence of a catalyst to yield mono-alkyl esters, which can be
used as fuel, and glycerin, which is removed. Used edible oils such
as vegetable oils have been considered as a source for the
production of biodiesel. However, the production of biodiesel from
used oil sources is limited by the presence of fatty acids. For
example, fatty acids can poison the catalyst used to produce
biodiesel from used oil.
[0012] There are several methods used in the trade to mitigate
these problems, but many of these address only one of the above
mentioned causes, thus failing to significantly extend the life of
the oil. Some methods introduce additional health and/or safety
concerns. Further, these methods do not significantly extend the
utility of the oil.
[0013] There is a need for new methods for the treatment of cooking
oil to extend its service lifetime. Further, such treatment methods
are needed to facilitate use of vegetable oil as an important
source of biodiesel.
SUMMARY
[0014] Particles coated with a filtering media comprising a polymer
having amine, amino, and/or imine group(s) are described herein for
removal of degradation byproducts and contaminants from food-grade
oil.
[0015] The particles are able to adsorb, absorb, or otherwise
coordinate multiple types of contaminants and/or degradation
byproducts of oil, not just one type. For example, the particles
are able to coordinate with two, three, or all of the following:
polymerized oils, free fatty acids, metal contaminants, and/or
polar contaminants.
[0016] Without being limited to any theory, the particles of this
invention may coordinate with, and thus remove, acid pendant groups
and/or oxidative products resulting from polymerization of the oil.
Free fatty acids may coordinate with an amine, such as a
positively-charged amine on the surface of the particles,
facilitating the removal of such contaminants. Metal contaminants
may coordinate with amine groups on the disclosed particles. Other
polar contaminants may also be attracted to and coordinate with the
positively-charged amine on the surface of the filter media. Thus,
the disclosed particles may be capable of removing more than one
type of contaminant found in edible, food-grade oil.
[0017] Furthermore, use of a polymer with a positively charged
amine (e.g. primary amine group), wherein the charge is created by
contact of the polymer with a strong acid, for example,
hydrochloric acid, appears to be more effective than polymers with
positively-charged amine groups created using a weak acid, such as
acetic acid.
[0018] Moreover, upon contact with the oil, the polymer can form a
fatty-acid electrostatic complex, upon which the charge on the
amine group can be removed to remove the fatty acid from the
polymer, wherein the polymer is then capable of being reused. This
can be done, for example, by changing the pH of the complex and/or
exposing the complex to a salt solution.
[0019] In one aspect, the invention relates to a method for
filtering contaminated edible oil, the method including the step of
contacting the edible oil with a filtering media acceptable for
food-grade use, wherein the filtering media includes a polymer
having amine and/or imine group(s). In certain embodiments, the
polymer has a primary amine group, a secondary amine group, or
both. In certain embodiments, the polymer has a primary amine
group, a secondary amine group, and/or a tertiary amine group.
Preferably, the polymer has positively charged amine groups and/or
positively charged imine groups. The polymer may be an amine salt,
for example.
[0020] Where the polymer includes a primary amine group, the
primary amine group may have a positive charge created by contact
of the polymer with an acid. Preferably, the acid is a strong acid
such as hydrochloric acid. The polymer may be a hydrochloric acid
salt.
[0021] In certain embodiments, the polymer is cross-linked, for
example, such that the polymer-coated particle remains porous. It
is preferred that the particles are porous.
[0022] In certain embodiments, the method filters contaminants by
attraction of the contaminants to the polymer, where the
contaminants include one, two, three, or all of the following
types: polymerized oils, fatty acids, metals, and polar
contaminants.
[0023] In certain embodiments, the polymer is or comprises
chitosan. For example, at least one primary amine of the chitosan
may be positively charged.
[0024] The particles are preferably at least partially coated with
the polymer. In certain embodiments, the particles are
substantially coated with the polymer. The particles may have an
average diameter of from about 1 to about 10 microns, for example.
Larger or smaller particles may be used as well. In certain
embodiments, the particles comprise diatomaceous earth. The
particles may comprise or be made of inorganic material. The
particles may comprise a metal oxide or semi-metal oxide, i.e., an
oxide of Si, Sn, Al, Ti, Bi, Fe, Zr, and/or Zn.
[0025] In another aspect, the invention relates to a particle
suitable for food-grade oil filtration including a substantially
inert porous inner particle and at least a partial coating on the
inner particle, wherein the coating comprises a polymer comprising
an amine group, an amino group, an imine group, or a combination
thereof. The description of embodiments above can be applied to
this aspect of the invention as well.
[0026] For example, the polymer may include a primary amine group
and/or a secondary amine group. The polymer preferably includes a
positively charged amine group. The polymer may be in the form of
an amine salt. The polymer may be cross-linked such that the
polymer coating is substantially porous. In certain embodiments,
the coating has a thickness of about 1 micron or less. The coating
may include the polymer chitosan. The particle may include, for
example, diatomaceous earth.
[0027] In yet another aspect, the invention relates to a filtration
device including a plurality of particles, wherein at least some of
the particles include a polymer acceptable for food use having at
least one amine group. The description of embodiments above can be
applied to this aspect of the invention as well.
[0028] For example, the amine is preferably positively charged.
[0029] In any of the aspects described above, further embodiments
include use of inorganic and/or organic particles. An example of
organic particles includes porous styrene beads. Also, in any of
the aspects described above, further embodiments include use of a
filtering media that does not require a inner particle core. For
example, in certain embodiments, polymer-coated particles are not
necessary; it is possible to use one or more of the above-described
polymers (e.g. polymers comprising an amine group, an imine group,
or both) without having been coated onto an inner particle core.
For example, the filtration media may include, consist essentially
of, or be made entirely of chitosan and/or PEI (LPEI and/or BPEI)
that is internally cross-linked, and which may or may not be in
particulate form. The filtration media may be fibrous, and does not
have to be in particulate form; for example, micro- and/or
nano-sized polymer fibers may be created via "electro-spinning"
technology, where the polymers include those described herein
comprising an amine group, an imine group, or both. Mixtures of
particles (coated and/or un-coated) and fibers may be used; for
example, fibrous pads loaded with particles may be used.
[0030] These embodiments of the present invention, other
embodiments, and their features and characteristics, will be
apparent from the description, drawings and claims that follow.
DETAILED DESCRIPTION
[0031] This disclosure is generally directed to particles and/or
polymers that include amine or imine moieties, and methods and
devices using the same. Such particles may be used for filtering or
removing contaminants in oxidizable compounds and compositions such
as those in edible or cooking oils, such as vegetable oil and oils
from rendered fat, such as lard or tallow. Such contaminants may
include decomposition by-products or oxidative products formed, for
example, upon heating or cooking with such oil. The types of
contaminants removed include free fatty acids, trace metals, and
polar materials.
[0032] It is contemplated that methods, compositions, particles,
devices and processes of the claimed invention encompass variations
and adaptations developed using information from the embodiments
described herein.
[0033] Throughout the description, where products, systems,
formulations, compositions, mixtures, and blends are described as
having, including, or comprising specific components, or where
processes and methods are described as having, including, or
comprising specific steps, it is contemplated that, additionally,
there are products, systems, formulations, compositions, mixtures,
and blends of the present invention that consist essentially of, or
consist of, the recited components, and that there are processes
and methods of the present invention that consist essentially of,
or consist of, the recited processing steps.
[0034] The mention herein of any publication, for example, in the
Background section, is not an admission that the publication serves
as prior art with respect to any of the claims presented herein.
The Background section is presented for purposes of clarity and is
not meant as a description of prior art with respect to any
claim.
[0035] Contemplated herein are particles and compositions for use
in filtering or removing contaminants in oils, such as edible oils.
In some embodiments, such a particle includes an inert porous inner
particle and a least a partial coating or layer disposed on the
surface of the inner particle. Such a coating may comprise an amine
group or a polymer that includes at least one of an amine or an
imine group.
[0036] Particles may include an inert porous inner particle that
may comprise, for example, diatomaceous earth, clays such as
kaolin, silica, silicates, alumina, siliceous clay,
montmorillonite, and/or metal oxides. However, any porous material
that is relatively inert and can be formed as an inner particle may
be used. Such particles may be at least partially coated or layered
with a polymer comprising an amino and/or an imine group. Such a
coat or layer may not significantly affect the porosity of the
inner particle. In an embodiment, a partial or full coating or
layer of the disclosed particles may be substantially thin, which
may create a high-surface area filter/binding medium. For example,
a coating may have a thickness of about 2 microns or less, or about
1 micron or less. Preferably, an inner porous particle is coated
with a disclosed polymer such that the coating does not
substantially interfere with the porosity of the inner particle,
e.g. does not block pores or channels of the inner particle.
[0037] Particles and/or an inner particle disclosed herein may be
prepared using any standard particulation process, for example
spray-drying, emulsion or suspension polymerization, and/or
precipitation. Coatings on inner particles that include polymers
comprising an amine and/or an imine group may be applied to inner
particles by, for example, spray-coating or precipitating the
polymer onto the inner particle, forming at least a partial
coat.
[0038] In some embodiments, a polymer for use on particles
disclosed herein may be cross-linked, for example, via additional
polymers that may include complementary functionality, or via
multifunctional cross-linkers. Such a cross-linked polymer may
provide for a partially or substantially porous coating on the
particles disclosed herein. Such cross-linking may for example
decrease the solubility of a polymer, and/or decrease or eliminate
dissolution of a disclosed particle in oil.
[0039] Since the size of particles correlates inversely with
surface area, smaller particles are in general preferred, for
example, particles with approximate average diameter from about 1
micron to about 10 microns, or particles less than about 15 microns
or less than about 10 microns. In some embodiments, particles can
be prepared with substantially high porosity that may increase the
available surface area by forming pores during particulate
formation.
[0040] The terms "amine" and "amino" are art-recognized and refer
to both unsubstituted and substituted amines, e.g., a moiety that
may be represented by the general formulas: ##STR1## wherein R50,
R51 and R52 each independently represent a hydrogen, an alkyl, an
alkenyl, --(CH2)m-R61, or R50 and R51, taken together with the N
atom to which they are attached complete a heterocycle having from
4 to 8 atoms in the ring structure; R61 represents an aryl, a
cycloalkyl, a cycloalkenyl, a heterocycle or a polycycle; and m is
zero or an integer in the range of 1 to 8. In certain embodiments,
only one of R50 or R51 may be a carbonyl, e.g., R50, R51 and the
nitrogen together do not form an imide. In other embodiments, R50
and R51 (and optionally R52) each independently represent a
hydrogen, an alkyl, an alkenyl, or --(CH2)m-R61.
[0041] The term "imine" refers to a moiety that may be represented
by ##STR2## where R11 is H, alkyl or aryl.
[0042] Polymers comprising an amine group may include an primary
(--NH.sub.2R), secondary (--NHR.sub.2), and/or tertiary amine
(--NR.sub.3) group. Such polymers may include a quaternary ammonium
cation or may be a quaternary ammonium salt. In some embodiments
polymer coatings contemplated herein include primary amines, for
example, about 30 or more primary amines, which may optionally
further include secondary amines. However, polymers for use in the
embodiments disclosed herein may include only secondary or tertiary
amine or amino groups, or may include at least one or more of
primary, secondary and tertiary amine or amino groups.
[0043] In some embodiments, a particle at least partially coated
with a disclosed polymer, and methods and devices disclosed herein
may be treated or washed with an acidic solution or compound, such
as an acidic solution comprising an inorganic acid, to create a
charged amine group and/or a stable salt complex. Such polymers may
be in the form of an amine salt, and may include salts formed with
formic, acetic, succinic, citric, lactic, maleic, fumaric,
palmitic, cholic, pamoic, mucic, d-glutamic, d-camphoric, glutaric,
glycolic, phthalic, tartaric, lauric, stearic, salicyclic,
methanesulfonic, benzenesulfonic, paratoluenesulfonic, sorbic,
puric, benzoic, cinnamic and the like organic acids. A particular
polymer may be in the form of an amine hydrochloric acid salt. An
acidic solution for use may be at a concentration that facilitates
the formation of the charged amine group, but may not be at a
concentration that would remove the amine group or other moieties
from the polymer.
[0044] Polymers for use in food grade applications, for example,
for filtering or removing contaminants such that an edible oil may
be re-used for example, for cooking or frying, may include
glycoaminoglycans such as polysaccharides, gums, starch or cationic
derivatives thereof, that include an amine group. For example, such
food-grade polymers may include chitosan, hyaluronic acid,
chrondoitin sulfate, and certain proteins or polypeptides. In
certain embodiments, film-forming polymers are used, which
facilitates coating of the particles.
[0045] Polymers for use in non-food grade application, for example,
for filtering or removing contaminants for use in the preparation
of biodiesel, may include polyalkyleneamines (PAA) such as
tetrabutylenepentamine, polyalkyleneimines (PAI), polyethyleneamine
(PEA) such as triethylenetetramine (TETA) and teraethylenepentamine
(TEPA), polyethyleneimines (PEI), such as branched
polyethyleneimine (BPEI), polyallylamines, and polyvinylamines.
Branched polyethylenimine, for example, may have at least moderate
branching. In certain embodiments, film-forming polymers are used,
which facilitates coating of the particles.
[0046] Non-food grade polymers that include an amine group and/or
an imine group also include such polymers as poly(amido-amine)
dendrimers, poly(alkylamino-glucaramide), and linear polymers with
a single primary, secondary or tertiary amine group attached to the
polymer units, such as poly(dimethylaminoethyl methacrylates),
dimethylamino dextran, and polylysines.
[0047] Particles for use in non-food grade applications may also
include an porous inner particle at least partially coated or
layered with a non-food grade polymer, or covalently bound to a
polymer comprising an amine or imine group through a silane moiety,
such as that produced by triethyoxy isocyano silane or
3-cyanopropyltrimethoxysilane. Covalently binding a polymer to the
surface of the inner particle may be particularly preferable when,
for example, the polymer comprising an amine and/or imine group is
at least slightly soluble in the edible oil. In a particular
non-food embodiment, a BPEI polymer is covalently bound to an inner
porous particle via a silane coupling moiety.
[0048] This disclosure also provides for methods for removing
contaminants from used edible oils. Such a method may comprise
contacting an oil with a filtering media that comprises a polymer
comprising at least one amine and/or imine group, such as the
polymers disclosed herein. The filtering media may be a plurality
of particles, wherein the particles include a porous inner core and
at least a partial coating of a polymer comprising at least one
amine and/or imine group. Such filtering media may also include
other particles or media that may also act to remove contaminants,
such as activated carbon, amorphous silica, metal silica, clay,
citric acid, silica, calcium silicate, magnesium silicate hydrate,
calcium silica hydrate, diatomite, and the like.
[0049] In some embodiments, a method for removing contaminants from
edible oil includes contacting the used or contaminated oil with a
particle comprising an inner porous core and at least a partial
coating disposed or bonded to the core that comprises a polymer
that includes at least one amine or imine group. The coating may be
attached or bound to the particle by covalent bonds, non-covalent
bonds and/or linked to the particle via Van der Waals forces,
hydrogen bonds, and/or other intermolecular forces.
[0050] In some embodiments, a method disclosed herein may further
comprise filtering the oil to remove the filtering media.
[0051] Edible oil may contain several types of contaminants after
use, such as after extended heating, that limit the viability of
the oil. Significant contaminants are associated with lipolysis and
the oxidative decomposition of edible oils. For example, oil may
begin to thicken during use which may be due to polymer formation
as a consequence of the polymerization of the double bonds present
in most edible oils. Another problem may be foaming, which may be a
result of released fatty acids coordinated with metals to form
surfactant like compounds that stabilize bubble formation and
foaming. Such foaming can be hazardous to the operator, due to
increased oil spattering. Another significant contaminant are free
fatty acids that may be formed via lipolysis or a hydration
reaction to form acid and, subsequently, alcohol. Further, polar
contaminants may also be a factor in oil decomposition, as well as
other contaminant products resulting from oxidation, such as
aldehydes and/or peroxides.
[0052] Without being limited to any theory, the particles of this
invention may coordinate with, and thus remove, acid pendant groups
and/or oxidative products resulting from polymerization of the oil.
Fatty free acids may coordinate with an amine, such as a
positively-charged amine on the surface of the disclosed particles,
facilitating the removal of such contaminants. Metal contaminants
may coordinate with amine groups on the disclosed particles. Other
polar contaminants may also be attracted to and coordinate with the
positively-charged amine on the surface of the filter media. Thus,
the disclosed particles may be capable of removing more than one
type of contaminant found in used edible oil.
[0053] In some embodiments, methods disclosed herein may result in
at least about 10%, at least about 15%, at least about 20%, at
least about 25%, or at least about a 30% reduction in total
contaminants. In other embodiments, methods disclosed here may
result in at least about 10%, at least about 15%, at least about
20%, at least about 25%, or at least about a 30% reduction in total
polar contents.
[0054] In a non-food embodiment, a particle for use in removing oil
contaminants may be rendered re-useable. For example, a particle
comprising a polymer comprising an amine group covalently bound to
an inner particle through a silane moiety, may, after usage, be
rendered re-usable by changing the pH or by exposing the particles
to a salt solution. Such processes may remove, for example, a fatty
acid contaminant coordinated with the amine group.
[0055] This disclosure also contemplates filtration devices such as
gravity feed filters and vacuum filters that comprise particles or
filter media disclosed herein. Filter media may be directly added
to a vat containing the used cooking oil or flowed through a filter
paper packet that contains filter media as part of the packet.
Cooking oil may be continuously filtered by using a device that
includes particles disclosed herein.
[0056] The examples that follow are intended in no way to limit the
scope of this invention but are provided to illustrate how to
prepare and use the particles and filter media in various
embodiments of this invention. Many other embodiments of this
invention will be apparent to one skilled in the art. Materials
used in the examples below include chitosan: Chitoclear CG400,
CG1600 from Primex (Siglufjordur, Iceland); coupling agents: Gelest
(Morrisville, Pa.); diatomaceous earth: Grefco Minerals,
Inc.(Burney, Calif.); and kaolin: Engelhard Corporation (Islin,
N.J.).
EXEMPLIFICATION
[0057] Non-Food Grade Media
Example 1
BPEI Coated Diatomaceous Earth I
[0058] Diatomaceous earth (DE) particles coupled with BPEI are
created using a silane coupling agent. 10 g of DE along with 100
mL's of isopropyl alcohol (IPA) and a magnetic stir bar is placed
into an Erlenmeyer flask. To this solution is added 0.5 mL
3-cyanopropyltrimethoxysilane and allowed to react for 2 hours.
After 2 hours, 1 mL BPEI is added and stirred for an additional 5
hours before filtering and washing the particles with IPA
2.times.'s and deionized water (DI water). The resulting particles
contain a coating of BPEI which can be tested for the presence of
amines by placing the final particle (0.5 g) into a scintillation
vial along with 10 mL of water and a spatula tip of a cellulosic
reactive dye with a fluorotriazine reactive dye that forms a
covalent bond to amines bound to the surface. These particles are
then filtered and washed with DI water 2.times.'s and brine to
remove complexed dye followed by water and dried. The resulting
particles yield a colored coating bound to the surface. Once the
particles are tested positive for surface amines, the particles are
then filtered and washed with a 0.05 M HCl solution in isopropanol
(IPA) then dried.
Example 2
BPEI Coated Diatomaceous Earth II
[0059] Diatomaceous earth (DE) particles coupled with BPEI is
created using a silane coupling agent. 10 g of DE along with 100 mL
isopropyl alcohol (IPA) and a magnetic stir bar is placed into an
Erlenmeyer flask. 0.5 mL 3-cyanopropyltrimethoxysilane is added to
this solution and allowed to react for 2 hours. After 2 hours, 1 mL
of BPEI is added and stirred for an additional 5 hours before
filtering and washing the particles with IPA 2.times.'s and
deionized water (DI water). The resulting particles contain a
coating of BPEI which can be tested for the presence of amines by
placing the final particle (0.5 g) into a scintillation vial along
with 10 mL's of water and a spatula tip of a cellulosic reactive
dye with a fluorotriazine reactive dye that forms a covalent bond
to amines bound to the surface. These particles are then filtered
and washed with DI water 2.times.'s and brine to remove complexed
dye followed by water and dried. The resulting particles yield a
colored bound to the surface. Once the particles are tested
positive for surface amines, the particles are then filtered and
washed with a 0.05 M HCl solution in isopropanol (IPA) then
dried.
Example 3
Chitosan Bound onto Diatomaceous Earth
[0060] Diatomaceous earth particles covalently bound with chitosan
are created by dissolving 2 g of chitosan (flakes) in 500 mL of
deionized water and 5 mL of 0.1 M hydrochloric acid. The
undissolved chitosan is filtered. Approximately 20 g of
diatomaceous earth is added to 400 mL of deionized water, 4 mL of a
triethoxy isocyano silane, and 2 mL of ammonium hydroxide and
stirred for 2 hours. The slurry is then filtered and washed with
deionized water. These functionalized diatomaceous earth particles
are then added to the chitosan solution and stirred for 8 hours.
The particles are filtered and washed, and finally dried in a
vacuum oven.
Example 4
Amine Modified Diatomaceous Earth
[0061] Particles of diatomaceous earth are functionalized with
amine groups by reacting 5 g of diatomaceous earth and 1.5 mL
trimethoxy aminopropyl silane in 100 mL deionized water. The
reaction is left overnight, and particles are filtered and washed
3.times. with deionized water and 1.times. with isopropanol.
Example 5
Amine-Modified Kaolin
[0062] Particles of Kaolin are functionalized with amine groups by
reacting 5 g of Kaolin and 1.0 mL trimethoxy aminopropyl silane in
100 mL deionized water. The reaction is left overnight, and
particles are filtered and washed 3.times. with deionized water and
1.times. with isopropanol.
Example 6
Polyethylenimine Modified Kaolin
[0063] Particles of Kaolin are functionalized with branched
polyethylenimine by reacting 5 g of Kaolin and 1.0 mL triethoxy
isocyano silane in 100 mL deionized water and 0.75 mL of ammonium
hydroxide. The reaction is left overnight, and 0.5 g
polyethylenimine is then added to the slurry. The particles are
filtered and washed 3.times. with deionized water and 1.times. with
isopropanol after 3 hours.
Example 7
Filtration of Oil
[0064] Canola oil is heated at 150.degree. C. for 10 days open to
air. After cooling, 10 mL of the heat-treated oil is added to 0.1 g
of particles and stirred for 12 hours. The oil is then filtered
using standard filter paper (as are all control samples), and the
absorbance is monitored at 600 nm using a UV-VIS spectrometer.
Un-cooked (virgin) canola oil is used as a blank, and the
percentage of contaminants removed are calculated by comparing the
absorbance of oil not treated with particles. A 13% reduction in
contaminants is observed for particles composed of polyethylenimine
modified diatomaceous earth prepared using Example 1. When
filtering is done with unfunctionalized diatomaceous earth
particles, no reduction in total polar contents or viscosity is
observed.
Example 8
Particle Charge Test
[0065] To test the particle charge, the particles created in
Examples 1-6 are subjected to a solution of Blue food dye No. 2,
which is a tetrasulfate and is statically attracted to a charged
surface. A control is used to validate the method, which is a known
particle used to filter free fatty acids from solution called
magnasol. The particles are subjected to a solution of blue dye,
which adheres to the surface of the particles. After washing, the
particles remain blue. This test is then applied to the particles
created in Examples 1-6 which show excellent color retention, and
which demonstrate the ability of these particles to pick up charged
species. Each of the particles created in Examples 1-6 passed the
test.
[0066] Food-Grade Media
Example 9
Chitosan Particles
[0067] Microparticles of chitosan are created by dissolving 2 g of
chitosan (flakes) in 500 mL of deionized water and 10 mL of 0.1 M
hydrochloric acid (HCl). Sodium hydroxide is then added slowly
while the solution is vigorously agitated until the chitosan
precipitated. The resulting particles are approximately 1-5 microns
in average diameter.
Example 10
2% Chitosan Stock Solution
[0068] The chitosan stock solution is created by dispersing 20 g of
chitosan (flakes) in 1000 mL of deionized water. To this solution
is added hydrochloric acid until a final pH of 5 was achieved by
slowly and incrementally adding 10 M HCl with continuous monitoring
the pH. This solution becomes a stock solution for chitosan
deposition. Several stock solutions are created with varying
viscosities as purchased from Primex ehf; CG10, CG110, CG400 and
CG800 (creates a 10, 110, 400 and 800 Cps solution at 2% with
acetic acid respectively).
Example 11
1% Chitosan CG1600 Stock Solution
[0069] The chitosan stock solution is created by dispersing 10 g of
chitosan (flakes) in 1000 mL of deionized water. To this solution
is added hydrochloric acid until a final pH of 5 is achieved by
slowly and incrementally adding 10 M HCl with continuous monitoring
the pH. This solution becomes a stock solution for chitosan
deposition. Stock solution of CG1600 is created with a viscosity of
1600 Cps as purchased from Primex ehf, using Primex CG1600 (Creates
a 1600 Cps solution at 2% with acetic acid).
Example 12
1% CG400 Diatomaceous Earth 1% Chitosan Coating
[0070] 10 g of diatomaceous earth is added to 100 mL's deionized
water with a stir bar to create a 10% solution (un optimized). To
this slurry is added 5 mL's of the 2% chitosan stock solution of
CG400. The slurry is allowed to stir for 1 hour. Once the slurry
becomes homogeneous, the polymer is precipitated out of solution by
the slow addition of 0.1 N sodium hydroxide until the pH stabilizes
above 7 and the chitosan precipitates onto the particles of
diatomaceous earth. The resulting particles contain a coating of
chitosan which is less than about one micron thick. The slurry is
filtered and washed with a 0.05 M HCl solution in isopropanol (IPA)
then dried.
Example 13
2% CG400 Diatomaceous Earth --2% Chitosan Coating
[0071] 10 g of diatomaceous earth is added to 100 mL's deionized
water with a stir bar to create a 10% solution (un optimized). To
this slurry is added 10 mL's of the 2% chitosan stock solution of
CG400. The slurry is allowed to stir for 1 hour. Once the slurry
becomes homogeneous, the polymer is precipitated out of solution by
the slow addition of 0.1 N sodium hydroxide until the pH stabilizes
above 7 and the chitosan precipitates onto the particles of
diatomaceous earth. The resulting particles contain a coating of
chitosan which is less than about one micron thick. The slurry is
filtered and washed with a 0.05 M HCl solution in isopropanol (IPA)
then dried.
Example 14
4% CG400 Diatomaceous Earth --4% Chitosan Coating
[0072] 10 g of diatomaceous earth is added to 100 mL's deionized
water with a stir bar to create a 10% solution (un optimized). To
this slurry is added 20 mL's of the 2% chitosan stock solution of
CG400. The slurry is allowed to stir for 1 hour. Once the slurry
becomes homogeneous, the polymer is precipitated out of solution by
the slow addition of 0.1 N sodium hydroxide until the pH stabilizes
above 7 and the chitosan precipitates onto the particles of
diatomaceous earth. The resulting particles contain a coating of
chitosan which is less than about one micron thick. The slurry is
filtered and washed with a 0.05 M HCl solution in isopropanol (IPA)
then dried.
Example 15
1% CG1600 Diatomaceous Earth --1% Chitosan Coating
[0073] 10 g of diatomaceous earth is added to 100 mL's deionized
water with a stir bar to create a 10% solution (un optimized). To
this slurry is added 10 mL's of the 1% chitosan stock solution of
CG1600. The slurry is allowed to stir for 1 hour. Once the slurry
becomes homogeneous the polymer is precipitated out of solution by
the slow addition of 0.1 N sodium hydroxide until the pH stabilizes
above 7 and the chitosan precipitates onto the particles of
diatomaceous earth. The resulting particles contain a coating of
chitosan which is less than about one micron thick. The slurry is
filtered and washed with a 0.05 M HCl solution in isopropanol (IPA)
then dried.
Example 16
2% CG1600 Diatomaceous Earth --2% Chitosan Coating
[0074] 10 g of diatomaceous earth is added to 100 mL's deionized
water with a stir bar to create a 10% solution (un optimized). To
this slurry is added 20 mL's of the 1% chitosan stock solution of
CG1600. The slurry is allowed to stir for 1 hour. Once the slurry
becomes homogeneous, the polymer is precipitated out of solution by
the slow addition of 0.1 N sodium hydroxide until the pH stabilizes
above 7 and the chitosan precipitates onto the particles of
diatomaceous earth. The resulting particles contain a coating of
chitosan which is less than about one micron thick. The slurry is
filtered and washed with a 0.05 M HCl solution in isopropanol (IPA)
then dried.
Example 17
4% CG1600 Diatomaceous Earth --4% Chitosan Coating
[0075] 10 g of diatomaceous earth is added to 100 mL's deionized
water with a stir bar to create a 10% solution (un optimized). To
this slurry is added 40 mL's of the 1% chitosan stock solution of
CG1600. The slurry is allowed to stir for 1 hour. Once the slurry
becomes homogeneous, the polymer is precipitated out of solution by
the slow addition of 0.1 N sodium hydroxide until the pH stabilizes
above 7 and the chitosan precipitates onto the particles of
diatomaceous earth. The resulting particles contain a coating of
chitosan which is less than about one micron thick. The slurry is
filtered and washed with a 0.05 M HCl solution in isopropanol (IPA)
then dried.
Example 18
Filtration
[0076] Canola oil is heated at 150.degree. C. for 10 days open to
air. After cooling, 10 mL of the heat-treated oil was added to 0.1
g of particles and stirred for 12 hours. The oil is then filtered
using standard filter paper (as were all control samples), and the
absorbance is monitored at 600 nm using a UV-VIS spectrometer.
Un-cooked (virgin) canola oil is used as a blank, and the
percentage of contaminants removed is calculated by comparing the
absorbance of oil not treated with particles.
[0077] A 31% reduction is observed for particles composed of
chitosan coated onto diatomaceous earth (Example 13)
Example 19
Filtration
[0078] Canola oil is heated at 180.degree. C. for 2 days open to
air. The total polar contents is measured using an Ebro FOM 310 oil
monitor. After cooling, 20 mL of the heat-treated oil is added to
2.0 g of particles and stirred for 12 hours. The oil is then
filtered using standard filter paper (as were all control samples),
and the samples are then re-heated back up to 180.degree. C. and
the total polar contents are read (note: oil needs to be hot to use
Ebro oil monitor). The viscosity is also measured using a
Brookfield viscometer before and after filtering with particles as
are control samples that are not heat-treated.
[0079] A 33% reduction in total polar contents is observed for
particles that had chitosan bound to them (example 12) after
subtracting out the baseline (unheated oil). The viscosity also
decreases after filtering with the particles bound with chitosan.
Lower viscosity indicates polymerized oils (e.g. hydrogenated
polymers) have been removed.
[0080] When filtering is done with unfunctionalized diatomaceous
earth particles, no reduction in total polar contents or viscosity
is observed.
Example 20
Charge Test
[0081] To test the particle charge, the particles created in
Examples 12-17 are subjected to a solution of Blue food dye No. 2,
which is a tetrasulfate and is statically attracted to a charged
particle surface. A control is used to validate the method, which
is a known particle used to filter free fatty acids from solution
called magnasol. These particles are subjected to a solution of
blue dye, which adheres to the surface of the particles. After
washing, the particles remain blue. This test is then applied to
the particles created in Examples 12-17, which show excellent color
retention, and which demonstrate the ability of the particles to
adsorb, absorb, or otherwise pick up charged species. Each of the
particles created in Examples 12-17 passed the test.
EQUIVALENTS
[0082] While specific embodiments of the subject invention have
been discussed, the above specification is illustrative and not
restrictive. Many variations of the invention will become apparent
to those skilled in the art upon review of this specification. The
full scope of the invention should be determined by reference to
the claims, along with their full scope of equivalents, and the
specification, along with such variations.
[0083] Unless otherwise indicated, all numbers expressing
quantities of ingredients, reaction conditions, and so forth used
in the specification and claims are to be understood as being
modified in all instances by the term "about." Accordingly, unless
indicated to the contrary, the numerical parameters set forth in
this specification and attached claims are approximations that may
vary depending upon the desired properties sought to be obtained by
the present invention.
* * * * *