U.S. patent application number 13/521911 was filed with the patent office on 2014-01-09 for multi-component pet food and method of manufacturing solid component.
This patent application is currently assigned to MARS, INCORPORATED. The applicant listed for this patent is Susan Finnegan, Aung Htoon, Estelle Lifran, Tanoj Singh, Robert Sleigh, Brad William Woonton. Invention is credited to Susan Finnegan, Aung Htoon, Estelle Lifran, Tanoj Singh, Robert Sleigh, Brad William Woonton.
Application Number | 20140010766 13/521911 |
Document ID | / |
Family ID | 44303725 |
Filed Date | 2014-01-09 |
United States Patent
Application |
20140010766 |
Kind Code |
A1 |
Sleigh; Robert ; et
al. |
January 9, 2014 |
MULTI-COMPONENT PET FOOD AND METHOD OF MANUFACTURING SOLID
COMPONENT
Abstract
The invention concerns multi-component packaged food products
which have been thermally processed to achieve commercial sterility
in a package, including at least a first component and a second
component in contact with (eg immersed in) the first component,
wherein said first component is comprised of a substantially
water-based, liquid, pasty or gelled food such as sauce, gel,
gravy, jus or the like, and wherein the second component consists
of one or more relatively hard, manufactured pieces that
substantially retain their initial shape and hard or crunchy
textural functionality for at least an expected shelf-life of the
product whilst exposed to the moisture content of the first
component.
Inventors: |
Sleigh; Robert; (Rose Bay,
AU) ; Woonton; Brad William; (Albury, AU) ;
Lifran; Estelle; (Hanches, FR) ; Singh; Tanoj;
(Tameit, AU) ; Htoon; Aung; (Kingsford, AU)
; Finnegan; Susan; (Wodonga, AU) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sleigh; Robert
Woonton; Brad William
Lifran; Estelle
Singh; Tanoj
Htoon; Aung
Finnegan; Susan |
Rose Bay
Albury
Hanches
Tameit
Kingsford
Wodonga |
|
AU
AU
FR
AU
AU
AU |
|
|
Assignee: |
MARS, INCORPORATED
McLean
VA
|
Family ID: |
44303725 |
Appl. No.: |
13/521911 |
Filed: |
January 12, 2011 |
PCT Filed: |
January 12, 2011 |
PCT NO: |
PCT/AU11/00030 |
371 Date: |
September 24, 2012 |
Current U.S.
Class: |
424/49 ; 426/285;
426/589; 426/72; 426/74; 514/769 |
Current CPC
Class: |
A23K 40/20 20160501;
A23K 20/174 20160501; A23K 20/26 20160501; A23K 40/10 20160501;
A23L 3/10 20130101; A23K 20/24 20160501; A23K 20/20 20160501; A23K
50/42 20160501; A23K 50/48 20160501 |
Class at
Publication: |
424/49 ; 426/589;
426/74; 426/72; 426/285; 514/769 |
International
Class: |
A23K 1/175 20060101
A23K001/175; A23K 1/00 20060101 A23K001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 12, 2010 |
AU |
2010900089 |
Claims
1. A multi-component packaged food product which has been thermally
processed to achieve commercial sterility in a package, including
at least a first component and a second component in contact with
(eg immersed in) the first component, wherein said first component
is comprised of a substantially water-based, liquid, pasty or
gelled food such as sauce, gel, gravy, jus and the like, and
wherein the second component consists of one or more relatively
hard, manufactured pieces that substantially retain an initial
shape and crunchy textural functionality for at least an expected
shelf-life of the product whilst exposed to the moisture content of
the first component.
2. A multi-component packaged food product which has been thermally
processed to achieve commercial sterility in a package, including
at least first and second components, wherein said first component
consists of a wet phase comprising water and other edible
substances and having a water activity of above 85 and which at
ambient temperature will typically have a liquid, viscous or gelled
consistency, and wherein said second component comprises solid
phase pieces at least partially surrounded by the first component
and which have separate and distinct physical characteristics from
the wet phase component, characterised by the solid phase pieces
comprising a manufactured matrix of inorganic but edible mineral
salts formed into a shape-stable object exhibiting a bulk water
activity value of 0.75 or below prior to thermal processing of the
packaged food product.
3. The multi-component packaged food product of claim 1, wherein
the second component pieces have an initial moisture content of
less than 10.0% w/w prior to incorporation into said first
component.
4. The multi-component packaged food product of claim 1, wherein
prior to thermal processing, the difference in water activity
between said first component and said second component pieces is in
the range 0.10 to 0.20.
5. The multi-component packaged food product of claim 1, wherein
the first component has a water activity of at least 0.9.
6. The multi-component packaged food product of claim 1, wherein
the second component solid phase pieces are substantially formed by
a process of compression.
7. The multi-component packaged food product of claim 1, wherein
the second component pieces comprise a matrix of inorganic
material, preferably including calcium mineral salts, and more
preferably a matrix comprised of calcium hydroxyapatite.
8. The multi-component packaged food product of claim 7, wherein
one or more materials selected from the group consisting of
nutraceutical actives, pharmaceutical actives, vitamins, functional
minerals, dentifrices and chelating agents are incorporated into
the calcium hydroxyapatite pieces.
9. The multi-component packaged food product of claim 7, wherein
palatant substances such as food starches, sugars and the like are
incorporated into the pieces or are present on the tabletted
calcium hydroxyapatite pieces.
10. The multi-component packaged food product of claim 7, wherein
the calcium hydroxyapatite is formulated and manufactured by dry
blending of tri-calcium phosphate (TCP), calcium hydroxide (CH) and
calcium sulphate (CS), preferably in a ratio of about 2TCP:1CH:1CS,
subsequent addition of water and appropriate tritration and
neutralization using a food-grade acid to an about neutral pH
value, followed by optional conditioning of the resulting slurry
prior to drying and granulating.
11. A food piece for incorporation in a thermally processed
multi-component wet packaged food product, said food piece being
formed substantially from a matrix of calcium mineral salt,
preferably calcium hydroxyapatite.
12. The food piece of claim 11, having a moisture content of less
than 10.0% w/w prior to incorporation in the food product.
13. The food piece of claim 11, additionally incorporating one or
more materials selected from the group consisting of nutraceutical
actives, pharmaceutical actives, vitamins, functional minerals,
dentifrices, chelating agents and food palatants.
14. The food piece of claim 11, wherein the food piece is
substantially formed by a process of compression tabletting.
15. (canceled)
16. (canceled)
17. A method of manufacturing a hard pet food piece for inclusion
as a component in a packaged multi-component wet pet food product,
comprising the steps of dry blending of tri-calcium phosphate
(TSP), calcium hydroxide (CH) and calcium sulphate (CS), subsequent
addition of water and appropriate titration and neutralization
using a food-grade acid, to an about neutral pH value, followed by
optional conditioning and maturing of the resulting slurry at
specified temperature conditions and for a predetermined time,
followed by drying and form-shaping into a crunchy piece having a
moisture content no greater than 10% w/w.
18. The multi-component packaged food product of claim 2, wherein
the second component pieces have an initial moisture content of
less than 10.0% w/w prior to incorporation into said first
component.
19. The multi-component packaged food product of claim 2, wherein
prior to thermal processing, the difference in water activity
between said first component and said second component pieces is in
the range 0.10 to 0.20.
20. The multi-component packaged food product of claim 2, wherein
the first component has a water activity of at least 0.9.
21. The multi-component packaged food product of claim 2, wherein
the second component solid phase pieces are substantially formed by
a process of compression.
22. The multi-component packaged food product of claim 2, wherein
the second component pieces comprise a matrix of inorganic
material, preferably including calcium mineral salts, and more
preferably a matrix comprised of calcium hydroxyapatite.
23. The multi-component packaged food product of claim 22, wherein
one or more materials selected from the group consisting of
nutraceutical actives, pharmaceutical actives, vitamins, functional
minerals, dentifrices and chelating agents are incorporated into
the calcium hydroxyapatite pieces.
24. The multi-component packaged food product of claim 22, wherein
palatant substances such as food starches, sugars and the like are
incorporated into the pieces or are present on the tabletted
calcium hydroxyapatite pieces.
25. The multi-component packaged food product of claim 22, wherein
the calcium hydroxyapatite is formulated and manufactured by dry
blending of tri-calcium phosphate (TCP), calcium hydroxide (CH) and
calcium sulphate (CS), preferably in a ratio of about 2TCP:1CH:1CS,
subsequent addition of water and appropriate tritration and
neutralization using a food-grade acid to an about neutral pH
value, followed by optional conditioning of the resulting slurry
prior to drying and granulating.
Description
FIELD OF THE INVENTION
[0001] The invention relates to the field of commercial pet food
manufacture. In particular, the invention relates to an improved
multi-component wet packaged pet food product and a method for
manufacturing a `non-wet` component for use in multi-component wet
packaged pet food products.
[0002] The present patent application claims priority from
Australian provisional patent application 2010900089, the contents
of its specification being hereby incorporated by way of
cross-reference.
BACKGROUND OF THE INVENTION
[0003] Multi-component wet packaged food products have been
marketed in most major markets for decades, and are well known in
particular also in the pet food manufacturing sector.
[0004] In the context of the present patent specification, the term
`multi-component` is used to denote a product having a wet phase,
or first food component, comprising as a major constituent water
(but not excluding other humectants) in which are dissolved or
suspended other edible substances, which is characterised by a high
water activity of typically above 85 to 90 and which at ambient
temperature will typically have a liquid, viscous or gelatinised
consistency. Typical representatives of such wet phase components
include gravies, jus, gels, sauces, etc. The multi-component
product will also incorporate a second (or more) solid phase
component that has separate and distinct physical characteristics
from the wet phase component and when immersed or otherwise in
contact with the wet phase first component will keep to a
substantial extent its shape.
[0005] A further characteristic of `wet` packaged foods is that
they are made shelf stable by heat treatment, e.g. retorted,
canned, pouched or bottled foods, or hot-packed aseptically sealed
products.
[0006] As an example, there are known canned pet food products in
which `solid` constituents such as rice, real or `artificial meat`
(ie meat analogue) chunks and vegetable pieces are suspended in a
syrupy (starchy) gravy, so that at lease two distinct textures are
present at the time of consumption by the animal, whereby the
shape-stable, distinct components remain separable from the
gravy.
[0007] A consistent feature of these products is that the solid
components tend to be relatively soft (ie chewy or resilient),
whether they be meat or poultry chunks, fish chunks, reformed meat
chunks, vegetables, extruded cereal-based or protein-based chunks
and even pieces of vegetables which are typically `hard` in raw
state, such as carrots. This is almost inevitable, given the heat
conditions applied in making the food commercially sterile in the
presence of water. Softening of the otherwise solid components also
follows during shelf-life storage in that these `take up` moisture
from the surrounding wet phase gel, gravy or the like. For the vast
majority of these products, this is not necessarily a problem,
since such solid phase components are likely to be reasonably
palatable, and textural `shortcomings` may not be too problematic,
in particular upon consumption by a mammal pet.
[0008] However, there is an increasing trend to design food
products, including pet food, that carry specific health benefits
by inclusion of `active` ingredients, such as nutraceutical or
pharmaceutical actives, vitamins, minerals, amongst others.
Unfortunately, many existing multi-component foods tend not to be
useful for carrying and protecting many of said active ingredients
during commercial sterilisation heat treatments, due to their
relatively high moisture levels. One way in which this problem has
been sought to be addressed in the past is by way of
micro-encapsulation of active substances in heat and/or moisture
resistant casings prior to embedding or infusion into manufactured
meat analogue chunks or suspension in the wet phase component.
[0009] Another aspect that is finding increasing attention in the
pet food industry in particular, is a requirement for product
differentiation by having multi-component foods which incorporate
distinct textures components, wherein a challenge remains in
creating a packaged wet product with crunchy or crispy textural
components that remain in such textural state within a liquid-based
matrix during the shelf-life of the product.
[0010] Accordingly, it is one object of the present invention to
provide a multi-component wet packaged food product, and a
component therefor, that includes a component able to remain
shape-stable and relatively `hard` or crunchy, to provide a point
of textural variety, during shelf-life of the product.
[0011] In another object, it would be beneficial for the relatively
hard or crunchy component to provide a suitable substrate for
carrying substances to provide functional benefits to the consumer
of the food product.
[0012] Yet a further object is to provide a method of manufacturing
a comestible, relatively hard or crunchy food component that will
remain in such state when used in the manufacture of heat-treated,
packaged wet food products, in particular pet food products.
SUMMARY OF THE INVENTION
[0013] In one overarching aspect the invention resides in a
multi-component packaged food product which has been thermally
processed to achieve commercial sterility in a package, including
at least a first component and a second component in contact with
(eg immersed in) the first component, wherein said first component
is comprised of a substantially water-based, liquid, pasty or
gelled food such as sauce, gel, gravy, jus or the like, and wherein
the second component consists of one or more relatively hard,
manufactured pieces that substantially retain their initial shape
and hard or crunchy textural functionality for at least an expected
shelf-life of the product whilst exposed to the moisture content of
the first component.
[0014] According to a more specific aspect of the invention, there
is provided a multi-component packaged food product which has been
thermally processed to achieve commercial sterility in said
package, including at least first and second components, wherein
said first component consists of a wet phase comprising water and
other edible substances and having a water activity of above 85 and
which at ambient temperature will typically have a liquid; viscous
or gelled consistency, and wherein said second component comprises
solid phase pieces at least partially surrounded by the first
component and which have separate and distinct physical
characteristics from the wet phase component, characterised by the
solid phase pieces comprising a manufactured matrix of inorganic
but edible mineral salts formed into a shape-stable object
exhibiting a bulk water activity value of 0.75 or below prior to
thermal processing of the packaged food product. In particular, the
food product is a pet food product.
[0015] The stable, low water activity of the solid phase pieces has
advantages in that these inclusions in a packaged wet pet food
product are stable in the food product upon storage, and promote
heat stability during thermal processing of the multi-component
food.
[0016] An advantage of such multi-component wet food product for
pets is that the second component will maintain a relatively hard
and crunchy texture throughout the normal shelf-life of the food
product, providing a different texture to that normally associated
with `chunks in sauce` style products, which mammal pets tend to
appreciate. This textural-stability within an aqueous environment
which the wet phase component represents may be leveraged to
provide functional advantages, e.g. the use of particular shape
profiles of the hard component pieces to promote good dental
hygiene in pet animals.
[0017] Preferably, prior to thermal processing, the difference in
water activity between said first component and said second
component pieces is in the range 0.10 to 0.20, advantageously the
gap is 0.15, the matrix of inorganic mineral salts ensuring that
the pieces will keep to a substantial extent their distinct shape
when immersed or otherwise in contact with the wet phase first
component. Preferably, said solid component pieces have a bulk
water activity of 0.70 or below prior to thermal processing, said
first (ie wet phase) component has a water activity of 0.9 or
above.
[0018] Preferably, the second component pieces comprise a matrix of
calcium mineral salts, most preferably a matrix of calcium
hydroxyapatite (`CHA`). This provides a relatively high degree of
hardness (or crunchiness) to the pieces which will be maintained
following thermal processing in a relatively `wet` environment. It
is believed that CHA has previously not been used in the
manufacture of comestible foods, although it has been used in
numerous other applications, as noted below.
[0019] Advantageously, the hard CHA matrix pieces will have an
initial moisture content of less than 10.0% w/w prior to
incorporation into the wet phase first component by immersion in
it.
[0020] It should be noted that palatability of the relatively hard
CHA matrix pieces is also an important aspect in the context of
multi-component pet foods. Accordingly, palatant substances may
advantageously be incorporated into the CHA matrix or onto the
exterior surface of the CHA matrix pieces, such as starches, sugars
and generally palatant substances typically employed in the pet
food manufacturing sector.
[0021] It has been surprisingly found that CHA matrix pieces
formulated and manufactured by dry blending of tri-calcium
phosphate (TSP), calcium hydroxide (CH) and calcium sulphate (CS),
subsequent addition of water and appropriate tritration and
neutralization (eg using a food-grade acid such as diluted
phosphoric acid) to an about neutral pH value, followed by optional
conditioning of the resulting slurry prior to drying and
form-shaping, will yield pieces which from a palatability point of
view are better than the case where other precursor substances are
used in manufacturing the CHA. Accordingly, the above manufacturing
process represents a further aspect of the present invention.
[0022] A preferred ratio of TSP:CH:CS is preferably in the range of
2:1:1, although this may be varied.
[0023] In yet a further aspect of the present invention, functional
ingredients are incorporated into the CHA matrix pieces prior to or
after the piece form-shaping step. These ingredients may include
one or more materials selected from the group comprising
nutraceutical actives, pharmaceutical actives, dentifrices and
chelating agents.
[0024] Preferably, the second component pieces are formed by a
process of compression, in particular compression tabletting. This
technique, in particular when using a CHA matrix formulation as
previously described, provides a highly form or shape stable food
component which retains shape and low water activity when in
contact with (or immersed in) wet phase components typically
employed in the pet food industry, even after undergoing cooking
processes designed to produce commercial sterility.
[0025] It will be appreciated by those skilled in the art that the
invention is of wide application in the field of commercial
packaged foods, in particular those intended for consumption by
pets. Also, the invention may be applied to a number of food
product formats, including chunks in gel, chunks in sauce, chunks
in loaf, pieces in gravy, pieces in gel and pieces in loaf (wherein
the piece can be any food piece). It would also be clear that the
product may be packaged in any suitable food container, including
steel cans, flexible aluminium or plastic trays, flexible pouches
or sachets, glass bottles or jars, etc. These aspects are known to
the multi-component food formulator.
[0026] It would also be clear to the skilled addressee that the
first component may be mingled or mixed with the second component
either before or after thermal processing of the second component,
or mixed and mingled to be thermally processed together.
[0027] The invention also does not preclude the presence of third,
fourth or more other components. In other words, the present
invention also foresees incorporation of solid phase pieces
comprising a manufactured matrix of inorganic but edible mineral
salts formed into a shape-stable object exhibiting a bulk water
activity value of 0.75 or below prior to thermal processing of the
packaged food product, into an otherwise `standard` packaged wet
food product having analogue meat pieces, meat chunks or other
solids, as currently commercially available.
[0028] In the following, a detailed description will be provided on
how to manufacture solid phase components in accordance with one of
the aspects of the invention, for subsequent use in a
multi-component wet packaged food product.
BRIEF DESCRIPTION OF THE FIGURES
[0029] FIG. 1 shows the chemical structure of apatite in enamel,
dentine and bone;
[0030] FIG. 2 shows the dissociation equilibrium equation for
calcium hydroxyapatite in general terms;
[0031] FIG. 3 shows a flow diagram of a scaled-up manufacturing
process in accordance with one aspect of the present invention to
yield a calcium hydroxyapatite which is preferably used in
formulating hard component pieces for use in a wet packaged food
product;
[0032] FIG. 4 shows a graph illustrating the relative hardness
values of solid food component pieces in tablet form, which
represent one aspect of the present invention, measured using a
qualitative tablet screw test, wherein the shaded area depicts the
perceived hardness value for the CHA-based tablet made in
accordance with that aspect of the invention; and
[0033] FIG. 5 shows two photographs of CHA-based tablets according
to the invention, and their appearance in a wet food product after
undergoing a retort cycle.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0034] Multi-component wet food products are know per se, and will
thus not be described further. Relevantly, different aspects of the
invention comprise (i) how to manufacture and (ii) provide hard,
manufactured pieces that substantially retain their initial shape
and hard or crunchy textural functionality for at least an expected
shelf-life of such multi-component food product whilst exposed to
the moisture content of the liquid, pasty or gelled, high water
activity food component, as well as (iii) a multi-component wet
food product incorporating such hard pieces. Therefore, the
following description will be limited to these aspects.
[0035] There are numerous mineral compounds that may be used to
manufacture a relatively hard and stable food piece for inclusion
in a multi-component food product in accordance with the present
invention. However, and in particular, calcium salts are
preferentially employed, both for their stability and inherent
texture, as well as for their contribution to dietary calcium.
[0036] Calcium hydroxyapatite [CHA:
Ca.sub.10(PO.sub.4).sub.6(OH).sub.2] has been identified as a
preferred matrix material which can be used for such purpose.
Consideration of the following factors led to such
appreciation.
[0037] CHA is a major mineral component in animal and human bodies,
especially in "load-bearing" tissues such as bone and teeth. For
example, in a typical cortical bone, which is composed of: 22 wt %
organic matrix, 69 wt % mineral, 9 wt % water, the major sub-phase
of the mineral component consists of sub-microscopic crystals of an
apatite of calcium and phosphate. CHA is otherwise also an
important inorganic material in biology and chemistry. Biological
apatites, which are the inorganic constituents of bone, tooth
enamel and dentin, however, are typically very variable in their
composition and morphology, and contain different impurities
including: Mg.sup.2+, K.sup.+, Na.sup.+, CO.sub.3.sup.-,
HPO.sub.4.sup.2-, Cl.sup.-, F.sup.-, and others. In general, these
impure biological apatites are designated as calcium deficient or
non-stoichiometric apatites.
[0038] FIG. 1 illustrates details on structure of different
biological apatites.
[0039] Synthetic CHA, on the other hand, is also frequently used in
biomineralization and biomaterial studies. The composition,
physicochemical properties, crystal size and morphology of
synthetic apatites tend to be sensitive to preparative conditions.
Common impurity phases in synthetic apatites prepared by
precipitation from supersaturated aqueous solutions are calcium
phosphate compounds such as amorphous calcium phosphates (ACP) with
variable compositions of
Ca.sub.3(PO.sub.4).sub.2-2x(HPO.sub.4).sub.3x.nH2O, octacalcium
phosphate (OCP),
Ca.sub.8(HPO.sub.4).sub.2(PO.sub.4).sub.4.5H.sub.2O, and calcium
hydrogen phosphate dihydrate (DCPD), CaHPO.sub.4.2H.sub.2O. In
addition, the incorporation of various ions as trace impurities
(hydrogen phosphate, carbonate, silicate ions, etc.) is very
difficult to prevent in any preparative procedure of CHA.
[0040] The most common reactions used for preparation of CHA in the
literature are:
##STR00001##
[0041] Consequently, and having regard to the manufacturing process
dependent shortcomings mentioned above, CHA may be used in
formulating food-compatible components that may impart a different
textural sensation when mingled, embedded or otherwise present in a
multi-component wet food product.
[0042] In this context, one has to take account of the fact that
the moisture and pH of the wet food component in which CHA-based
hard food component pieces would be incorporated greatly influences
the stability of the CHA material. The dissociation equilibrium
equation for calcium hydroxyapatite is shown in FIG. 2.
[0043] On dissociation, hydroxyapatite produces two ions, phosphate
and hydroxyl, capable of accepting protons. Hydroxyapatite is,
therefore, a weak base. Phosphate is capable of accepting three
protons and has three possible pK values: 12.3, 7.2 and 2.1. As the
pH of the aqueous phase drops, the ratio of the concentrations of
the various forms of phosphate changes as more and more phosphate
is progressively protonated. Similarly, as the pH drops, hydroxyl
ions are protonated and the [OH] ion concentration reduces.
[0044] Knowledge of the relationship between pH and pK allows
prediction of the behaviour of the phosphate and relation of this
to mineral dissolution. At near neutral pH, say pH 7.2, the ratio
of mono- and di-hydrogen phosphate can be calculated, which means
that when the pH of the solution is equal to the pK, the
concentration of mono- and di-hydrogen phosphate is the same.
Similar calculations can be applied to the other pK values but
these are a long way outside the physiological values of pH which
are experienced in vivo or in a food matrix.
[0045] It is interesting to calculate the ratio of phosphate ion to
mono-hydrogen phosphate at near neutral pH because it is the
concentration of the un-protonated phosphate, together with
hydroxyl ion, which affects the dissociation of CHA.
[0046] Against this background, some key points as to the
suitability of using CHA in the manufacture of a food component are
summarised below: [0047] The dissociation constant (pK) defines the
ratio of the concentrations of the dissociated ions and the
undissociated acid. [0048] The Henderson-Hasselbach equation
relates pK, pH and the ratio of salt concentration to
un-dissociated acid. The buffering action of any weak acid-salt
mixture is at its greatest close to the pK of the weak acid.
Phosphate can accept three protons and has three possible pK
values, 12.3, 7.2 and 2.1. [0049] In the dissociation of
hydroxyapatite, it is the concentration of non-protonated phosphate
and hydroxyl ions which are important. As the pH becomes more acid,
more phosphate is protonated resulting in the dissolution of more
mineral. [0050] In food, it is important to consider buffering
capacity of proteins present in a food matrix. Moisture in food and
its saturation with respect to calcium and phosphate and the
presence of other salts/ions can greatly impact on the stability of
CHA dental active material. [0051] Calcium phosphate-based
biomaterials have been in use in medicine and dentistry for over 20
years because of their excellent biocompatibility with human
tissues, e.g. dental implants, percutaneous devices, periodontal
treatment, alveolar ridge augmentation, orthopaedics, maxillofacial
surgery, otolaryngology, and spinal surgery. [0052] Hydroxyapatite
is also currently used for fractionation and purification of a wide
variety of biological molecules, such as subclasses of enzymes,
antibody fragments, and nucleic acids.
[0053] Having established the suitability of using CHA in
formulating a food component that may be used in a multi-component
wet food product, the challenge was then to identify and provide a
process for the manufacture of CHA that is physiologically
acceptable and which material may then be used to provide a
substrate for or mayor constituent of a texturally hard or crunchy
food piece.
[0054] In accordance with one aspect of the invention, such process
was devised. It comprises the steps of mixing suitable
CHA-precursor ingredients, titrating with water and a suitable
food-grade acid to achieve an adequately neutralised slurry, and
subjecting the slurry through various conditioning, maturing and
drying steps, some of which are optional, to obtain a material
which can then be form-shaped into food pieces, either alone or in
combination with other constituents.
[0055] A process flow diagram for manufacturing a preferred
food-grade CHA is illustrated in FIG. 3, using exemplary process
parameter values and quantities of ingredients as determined
suitable from pilot scale tests.
[0056] This process involves the dry blending of (3 Kg) tri-calcium
phosphate (TCP), (1.5 Kg) calcium hydroxide (CH) and (1.5 Kg)
calcium sulphate (CS). This is best performed using a rotary drum
mixer as it was found to yield optimum mixing/blending of the dry
ingredients as compared with other mixers, such as a pin-mixer. The
dry blended ingredients are then placed into a Hobart mixer, and a
sufficient quantity of water is added to make a thick slurry. The
slurry is slowly neutralized by the addition of acid (80%
phosphoric acid diluted 1:1 with water) with continuous
stirring/mixing. The pH of the starting slurry was >12.0 and had
a sandy/gritty texture, whereas the resulting titrated material
slurry exhibits a smooth `plaster-like` texture with a neutral pH
value of around 7.0; total weight of the aqueous slurry at this
stage set to 12 Kg.
[0057] The neutralized (titrated) slurry material is then subjected
to an optional conditioning stage in suitable conditioning vessels.
Suitable conditioning parameters are 75.degree. C. at 100% relative
humidity for three hrs. An optional maturation stage may then
include resting the conditioned material at room temperature
(23.degree. C.) for no less than 12 hrs, preferably 24 hrs, before
the material is fully dried at 80.degree. C. for such time as to
achieve a dry product with preferably not more than 10% w/w
moisture content.
[0058] This dried CHA material can then be granulated or pulverized
and subsequently form-shaped into discrete pieces.
[0059] A preferred form-shaping process resides in direct dry
compression tabletting of the CHA, either alone or with a small w/w
% of added constituents such as palatants and tabletting aid agents
(eg Mg Sterate) to form a water repellent though not entirely water
impervious outer surface and to a compression degree sufficient to
have a shape-stable object that can be handled during food product
manufacturing operations without breaking up. The specific shape of
the pieces is not limiting, as is the weight, although typical
tablet sizes and lenticular shapes such as encountered in the
pharmaceutical industry provide guidance in achieving form-stable
pieces.
[0060] For CHA-matrix, hard tabletted pieces to be successfully
incorporated into multi-component wet (pet) food products, whereby
these maintain shape integrity and textural quality within the
multi-component product, these must meet requirements for crunch
and crisp wet metrics for such products in the marketplace.
[0061] To determine this, CHA tablets were manufactured using
slight variations of the above general formula/recipe and
compressed to different degrees to establish adequate compression
values (and formulations) required for such tabletted CHA-matrix
pieces to maintain adequate `crunchiness` (or hardness) over the
intended shelf-life in a multi-component wet pet food product.
[0062] The relative hardness of the solid pieces is tested after
tabletting, prior to inclusion into the multi-component wet food
product, as well as after retort processing of the multi-component
food product to a degree which achieves commercial sterility. It
will be appreciated that the degree of `crunchiness` that will be
present at the end or past the shelf-life will depend to some,
although small degree, also on the actual water activity of the
specific liquid food component in which the hard CHA-matrix pieces
are immersed. Also, being a relative sensory value, it is not
possible to provide a preferred formulistic or value-specific
hardness, softness or crunchiness indicator. The `softness` and
`hardness` of CHA-matrix tablets is thus better indicated on a
qualitative (yet ultimately arbitrary) hardness scale, such as
illustrated in FIG. 4. It would seem from tests carried out that
medium relative hardness values, as depicted by the highlighted
area in FIG. 4, should be aimed for when using the CHA-formulated
tablets as per the invention.
[0063] CHA materials produced were typically also more suitable for
tabletting when they had been dried further (towards a lower w/w %
moisture content) and pre-granulated (rather than pulverised).
[0064] FIG. 8, left hand side, illustrates actually manufactured
CHA-matrix tablets having a medium relative hardness, according to
the recipe noted above, whilst the right hand side of FIG. 8 shows
a commercial `meat chunks in gravy` food product, which includes
soft or chewy food components in a gravy as well as a number of
solid and crunchy tablets, after being retorted. This photo shows
that the tablets maintain their shape-integrity and have not been
disintegrated or substantially softened as consequence of retorting
in an aqueous environment. Subsequent to shelf-life storage, the
multi-component food product showed almost unchanged
characteristics, ie in the finished multi-component food product,
the shape integrity of the hard tabletted pieces was maintained and
the textural quality met the requirements for crunch and for crisp
wet metrics required for such products in the marketplace.
* * * * *