Note: Descriptions are shown in the official language in which they were submitted.
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TRIPOLYPHOSPHATE PET FOOD PALATABILITY ENHANCERS
[0001] This invention generally relates to ingestible compositions having
increased
palatability for animals, whereby a superior palatability enhancer is used as
a component or
as a coating for the ingestible.
[0002] Pet food manufacturers have a long-standing desire to provide foods
that combine
high nutritional value, and resistance to decomposition and bacterial
contamination, with low
production costs. In addition, and with particular regard to cat foods, pet
food manufacturers
desire a high degree of palatability that can be attained at low cost.
[0003] Domestic animals, particularly cats, are notoriously fickle in their
food preferences.
As a result, their owners frequently change types and brands of cat food in
order to maintain
their pets in a healthy and contented condition. For the most part, the only
way to determine
the gastronomic preferences of cats is by trial and error.
[0004] Dried animal or pet food products are widely marketed for pets such as
cats and
dogs. Generally, dried pet food products sold commercially have a relatively
low moisture
content of less than about 15% by weight and can provide excellent nutrition
for animals
because the low moisture content permits a wider variety of ingredients and a
better
nutritional combination of ingredients as well as long term product stability.
[0005] Dry and semi-dry foods are generally preferred by manufacturers and pet
owners
alike because such foods are more convenient to store and use, and because of
the higher
nutritional content than high-moisture pet foods. However, many animals, and
particularly
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cats, are picky eaters desiring a high degree of palatability. There remains a
need for a low-
moisture pet food with a high degree of palatability.
[0006] Dry pet foods exhibit a number of advantages over pet foods having
higher moisture
contents. The dry foods are generally more nutritious on an equal weight
basis, require less
expensive packaging, have better keeping qualities and are more convenient to
use.
[0007] Typically, such dried food products are expanded or puffed products
produced by
extrusion techniques. Extrusion cooking processes for the production of dried
pet foods have
been a significant factor in the growth of this market segment because of the
better cooking
achieved with this type of process, better mixing of ingredients, as well as,
the desirable
texture achieved with a puffed or expanded product.
[0008] Dry products produced by this type of process are generally well
accepted by the
animal but they are significantly lower in palatability than canned or high
moisture products
that typically are all meat products with a moisture content above 50% by
weight. This
problem is especially pronounced with cat foods since cats have long been
recognized as
sporadic or "finicky" eaters, and they generally ignore dried food products in
preference to
meat and high moisture foods. Therefore, although a dry product is extremely
convenient to
use by the pet owner and exceptionally nutritious, a need has continuously
existed for
additives or ingredients which can be included in the food product to increase
the palatability
of the product, without reducing the nutritive properties.
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[0009] There are a number of processes disclosed in the art for improving the
palatability
and other characteristics of dry pet food. Palatability may be enhanced by the
application of
liquid or dry flavorings as a coating, however; flavors alone have a limited
impact on
improving palatability.
[0010] Palatability enhancers for low moisture pet foods include various
surface coating
compositions. Liquid or dry animal digest coatings are widely used to enhance
palatability,
and animal digest is also used in a liquid combination with phosphoric acid.
Dry animal
digest may be used in a two step coating process with liquid phosphoric acid.
Dry application
of sodium acid phosphate, which may be used in combination with animal digest,
is also
known. For example, known palatability enhancers include surface coatings of
phosphoric
acid; a combination of fat with hexamic, phosphoric or citric acid; and a
mixture of
phosphoric acid and citric acid.
[0011] One problem is that liquid phosphoric acid cannot be added to dry
flavors; therefore,
palatability enhancers that combine these two ingredients are not commercially
available.
Unfortunately, dry phosphoric acid is relatively unobtainable, uneconomical,
and difficult to
handle. However, U.S. Pat. No. 4,215,149 discloses that the dry application of
sodium acid
phosphate (SAP) is equal or superior to phosphoric acid.
[0012] U.S. Pat. No. 3,115,409 to Hallinan et al. is directed to pet foods
having a high acid
content and a minimum disclosed moisture content of 30 percent. The pH of the
pet food is
adjusted to low levels and then the pet food is cooked to alter the
proteinaceous material
contained therein. This type of procedure is commonly practiced in the food
industry to
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inhibit bacterial decomposition and to hydrolyze proteinaceous materials in
order to develop
more flavorful products. In order for the reaction to take place, relatively
large quantities of
water are necessary. U.S. Pat. No. 3,139,342 to Linskey relates to an animal
food process
wherein the food is produced in the form of pellets, which may be coated with
various taste
enhancing and/or nutrition supplementing materials, e.g., fat and Vitamin A.
U.S. Pat. No.
3,203,806 to Young relates to a pet food having acetamide and acetic acid
incorporated
therein for improved palatability. The palatability improvers may be added to
dry or semi-dry
pet foods by being sprayed thereon.
[0013] U.S. Pat. No. 3,539,357 to Appleman et al. relates to a method of
preparing animal
food having relatively high moisture content whereby heated meat tissue is
treated with an
acid to produce a breakdown of the proteins and comminuting the treated
material. U.S. Pat.
No. 3,615,647 to Kassens is directed to a porous, expanded animal food in the
form of chunks
coated with fat which coating is, in turn, overlaid with a coating of dextrin.
U.S. Pat. No.
3,679,492 to Mohrman et al. relates to a method for improving the palatability
of dry cat food
by coating particles of the food with fat and a flavor enhancing acid,
specifically, citric,
phosphoric or hexamic acids. U.S. Pat. No. 3,708,306 to Appleman relates to a
pet food
containing psyllium byproducts wherein dicalcium phosphate is incorporated.
The dicalcium
phosphate is blended into the pet food together with other ingredients in the
form of a batter
which is then baked. U.S. Pat. No. 3,930,031 to Kealy is directed to a cat
food composition
having a coating comprising a flavor enhancing mixture of phosphoric and
citric acids.
[0014] U.S. Patent No. 5,186,964 discloses the use of dry or liquid Sodium
Acid
Pyrophosphate (SAPP) as part of a coating to improve palatability of dry pet
food.
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U.S. Patent No. 6,254,920 B1 and U.S. Patent No. 6,350,485 B2 disclose
improving
palatability of dry and semi dry cat food using Tetrasodium Pyrophosphate
(TSPP). Several
other phosphate salts have been suggested, but none have been successful in
replacing TSPP
or SAPP.
[0015] Current compositions and methods remain limited in the resulting degree
of
increased palatability.
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SUMMARY OF THE INVENTION
[0016] The enhancers of the present invention provide a superior enhancement
in the
palatability of ingestible compositions, particularly for dry and semi-dry pet
foods. The
enhancers of the present invention are relatively low in cost, easily used and
can be
incorporated into many forms and formulas of ingestible product.
[0017] Therefore, according to one aspect of the present invention, a method
is provided in
which a palatability enhancer containing at least one tripolyphosphate salt in
an amount
effective to enhance palatability is applied to an extruded pet food
composition to increase
palatability. The tripolyphosphate salt can be a sodium salt, a potassium
salt, or mixed
sodium and potassium salts. For purposes of the present invention "applied" is
defined as
including both adding at least one tripolyphosphate salt to a pet food
formulation in an
amount effective to enhance the palatability of the extruded composition prior
to extrusion, as
well as coating an extruded pet food composition with a palatability-enhancing
quantity of at
least one tripolyphosphate salt after the pet food composition has been
extruded.
[0018] The palatability enhancer, which preferably includes from about 0.1% to
about 99%
by weight of one or more sodium tripolyphosphate salts, is preferably
topically applied to dry
pet food pellets or kibbles after extrusion. Other constituents of the
palatability enhancer can
include one or more ingredients selected from meat, meat by-products, fish,
fish by-products,
dairy, dairy by-products, microbial proteins, vegetable proteins, amino acids,
and
carbohydrates. Additional ingredients, including other natural and artificial
flavors, other
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palatability-enhancing acids and salts thereof, vitamins and mineral
supplements, anti-
oxidants, preservatives, inorganic salts, and the like, may also be utilized.
[0019] The palatability enhancer can be applied to the kibbles as a dry powder
via a dusting
process, or may be sprayed onto the kibbles as a liquid. The palatability
enhancer is
preferably applied in an amount sufficient to contribute from about 0.01 to
about 5.0% by
weight of one or more tripolyphosphate salts by weight to the pet food
composition.
[0020] The present invention also includes palatability enhancing compositions
utilized in
the inventive method. Therefore, according to another aspect of the present
invention,
palatability enhancing compositions for extruded pet food compositions are
provided
containing at least one tripolyphosphate salt in an amount effective to
enhance palatability
and at least one ingredient selected from animal products, animal by-products,
fish products,
fish by-products, dairy products, dairy by-products, sources of microbial
proteins, vegetable
proteins, carbohydrates and amino acids.
[0021] The present invention also includes extruded pet food compositions
coated with the
palatability enhancing compositions of the present invention.
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DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0022] The palatability enhancing compositions of the present invention are
prepared from
tripolyphosphate salts, and, in particular, sodium tripolyphosphate (STPP) and
potassium
tripolyphosphate (KTPP), as well as mixed salts of sodium and potassium
tripolyphosphate.
Preferably, the palatability enhancing compositions contain one or more sodium
tripolyphosphate salts derived from STPP. Accordingly, the preferred
embodiments will be
described with reference to STPP. However, the KTPP and mixed tripolyphosphate
salts of
sodium and potassium may be substituted for STPP and the use of KTPP and mixed
tripolyphosphate salts are included within the scope of the present invention.
[0023] Methods according to the present invention apply the palatability
enhancing
compositions of the present invention to extruded pet food compositions in a
quantity
sufficient to enhance palatability of the finished pet food product.
[0024] STPP has the formula Na5P3010. When dissolved in solution, depending
upon pH,
STPP may partially or completely dissociate to form one or more additional
species including
the free tripolyphosphate anion, and mono-, di-, tri- and tetra-sodium salts
thereof, in which,
after liquid product has dried on an extruded pet food product, one, two,
three, four or five
sodium atoms are replaced with hydrogen atoms. Accordingly, palatability
enhancers of the
present invention in which the STPP has been dissolved in solution and
permitted to equili-
brate are referred to as containing one or more sodium tripolyphosphate salts,
and for
purposes of the present invention "STPP" and "sodium tripolyphosphate" is
defined as
including all possible salts and salt combinations. The palatability enhancers
can be liquid
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palatability enhancers or palatability enhancers that are subsequently dried
by evaporation,
lyophilization, and the like to form a dry product.
[0025] The exact ratios of the five tripolyphosphate salts to the total
tripolyphosphate
content can be readily determined by one of ordinary skill in the art knowing
the final
solution pH without undue experimentation by employing the Henderson-
Hasselbach
equation and using the pKa's of the sodium tripolyphosphate salts, which are
known physical
constants.
[0026] When dry-blended with other dry palatability enhancer ingredients the
STPP will
not dissociate. STPP added in dry form to essentially dry palatability
enhancer formulations
will remain essentially STPP.
[0027] In accordance with this invention, the palatability enhancer is applied
to the surface
of dry pet food, usually in the form of pellets or kibbles, and may be used in
conjunction with
either other palatability enhancing ingredients. While the palatability
enhancers of the present
invention can be used as an ingredient incorporated in the composition of the
pet food
product itself, used as a coating less enhancer is required and the animal
receives the maxi-
mum exposure to the enhancer. The enhancer compositions used for coating can
be liquid or
dry. This will depend on a number of factors including the target animal, the
product to be
coated, costs of ingredients, flavoring agent to be used and coating equipment
to be used.
[0028] As referred to within this description, pet foods generally relate to a
nutritionally
balanced mixture of proteinaceous and farinaceous materials having a moisture
content of
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about 50% or less by weight. Such mixtures are known as dry or semi-dry pet
foods to those
skilled in the art, and the palatability enhancer is applied to pieces of the
dry or semi-dry
food. The pet food compositions described herein are not intended to be
limited to a specific
listing of ingredients because such ingredients will depend on such factors
as, for example,
the desired nutritional balance for the specific type of pet, and availability
of ingredients to
the manufacturer. In addition to the proteinaceous and farinaceous materials,
the pet food
composition may include vitamins, minerals, and other additives such as
flavorings,
preservatives, emulsifiers and humectants. The nutritional balance, including
the relative
proportions of vitamins, minerals, fat, protein and carbohydrate, is
determined according to
dietary standards known in the veterinary art. For example, the nutritional
balance of a cat
food composition is determined according to the known dietary requirements for
cats.
[0029] Suitable proteinaceous material may include any material having a
protein content of
at least about 15% by weight including vegetable proteins such as soybean,
cotton seed, and
peanut; animal proteins such as casein, albumin, and fresh animal tissue
including fresh meat
tissue and fresh fish tissue; and dried or rendered meals such as fish meal,
poultry meal, meat
meal, bone meal and the like. Other types of suitable proteinaceous materials
include wheat
gluten or corn gluten, and microbial proteins such as yeast.
[0030] Suitable farinaceous material may comprise any material having a
protein content of
less than about 15% by weight and containing a substantial proportion of
starches or
carbohydrates, including grains such as corn, milo, alfalfa, wheat, barley,
rice, soy hulls, and
other grains having low protein content. In addition to the proteinaceous and
farinaceous
materials, other materials such as whey and other dairy by-products, as well
as other
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carbohydrates may be added. In addition, known flavorings including, for
example, corn
syrup or molasses, may be added.
[0031] In one example, the palatability enhancer is applied to a dry cat food
composition.
Generally, the term cat food composition as used herein applies to
commercially sold,
nutritionally balanced food compositions that are intended to provide
substantially the sole
diet for a cat. Thus, such compositions may be described as having a minimum
protein
content at which cat health is maintained. However, the minimum protein
content of the food
varies according to the age and breeding status for the animal. For example, a
nutritionally
balanced cat food composition for breeding females and kittens requires a
minimum protein
content of at least about 28% by weight on a dry matter basis. A nutritionally
balanced cat
food composition for non-breeding and adult cats requires a minimum protein
content of
about 26% by weight on a dry matter basis. More typically, the protein content
of commer-
cially available cat food compositions for adult, non-breeding cats is about
30% by weight on
a dry matter basis, to insure that the food meets the nutritional requirements
of any cat.
[0032] For example, a typical formula well known in the art for a dry cat food
composition
to which the palatability enhancer is applied is as follows:
0%-70% by weight grain-based meal or flour, such as corn, wheat, barley or
rice;
0%-30% by weight animal by-product meal, such as poultry or beef meal;
0%-25% by weight corn gluten meal;
0%-25% by weight fresh animal tissue, such as poultry or beef tissue;
0%-25% by weight soybean meal or flour;
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0%-25% by weight fresh fish tissue;
0%-20% by weight seafood-based meal;
0%40% by weight animal fat;
0%-10% by weight high fructose corn syrup;
0%40% by weight dried molasses;
0%-1.5% by weight phosphoric acid; and
0%-1.5% by weight citric acid.
[0033] Additionally, vitamins and minerals are added according to known
American
Association of Feed Control Officials (AAFCO) guidelines. Such AAFCO Cat Food
Nutrient profiles include calcium carbonate, potassium chloride, sodium
chloride, choline
chloride, taurine, zinc oxide, ferrous sulfate, vitamin E, vitamin A, vitamin
B12, vitamin D3,
riboflavin, niacin, calcium pantothenate, biotin, thiamine mononitrate, copper
sulfate, folic
acid, and pyroxidine.
[0034] Dry pet food may be prepared by a variety of methods. One such method
that is
widely used on commercial basis is the cooker-extruder method. In the cooker-
extruder
method, dry ingredients are first blended together to form an admixture. This
admixture is
transferred into a steam conditioner where it is sufficiently moistened to
become extrudable.
The admixture then enters a cooker/extruder where it is cooked at an elevated
temperature
and pressure and then forced out of the apparatus through a die. This die
forms the extruded
product into a specific shape. Individual pieces of product are created by
periodically slicing
off the end of the extruded stream of product. The individual pieces, or
kibbles, are then
dried in a hot air dryer. Generally, the product is dried until it contains
less than about 15
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percent moisture, and preferably about 9 to 12 percent moisture. The dried
particles or pieces
are then transferred by bulk conveyor to a coating drum and sprayed with
animal fat. Other
liquids such as, for example, citric acid or phosphoric acid may alternatively
be applied to the
pieces, or applied in addition to the animal fat. The resulting pellets or
kibbles constitute the
basal composition to which a coating of the palatability enhancer is applied.
[0035] Coating, as used herein, refers to the topical deposition of the
palatability enhancer
onto the surface of the basal composition, such as by spraying, dusting, or
the like. For exam-
ple, kibbles of uncoated, extruded basal cat food can be placed in a container
such as a tub or
coating drum for mixing. A fat, such as lard or tallow, is heated and then
sprayed onto the cat
food in any convenient manner to obtain a coating of the kibbles. The coating
need not be a
continuous layer, but preferably is uniform. After the fat cools, the
palatability enhancer may
be applied as either a dry power or a liquid while the product is mixing. A
liquid palatability
enhancer is typically sprayed on while a dry palatability enhancer is
typically dusted on,
preferably through a mesh screen to make the application more uniform on the
kibbles.
Alternatively, a palatability enhancer can be mixed with the fat and applied
concurrently.
Note that multiple coatings may be applied to achieve uniformity of the
coating.
[0036] STPP is commercially available as a dry powder, granules, or an
encapsulated form
from Haifa Chemicals, Ltd. Of Israel. The STPP may be combined with other
palatability-
enhancing ingredients such as animal products and by-products, fish products
and by-
products, dairy products and by-products, microbial proteins, amino acids,
carbohydrates, and
the like. The exact proportion of STPP and other palatability-enhancing
ingredients used in
the palatability enhancer, as well as the relative proportion of the
palatability enhancer to the
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finished animal food product, may be varied and are influenced by such factors
as relative
availability of the ingredients, cost, and health of the animal. In addition,
the palatability
enhancer described herein is not intended to be limited to a specific listing
of ingredients
because such ingredients will similarly depend on availability and cost of
ingredients to the
manufacturer.
[0037] For purposes of the present invention "animal" products and by-products
are defined
as including meat product and by-products from animal species other than fish.
Examples of
animal products and animal by-products that can be used include, but are not
limited to,
products and by-products derived from beef, pork, sheep or lamb, poultry,
duck, and the like.
[0038] Examples of fish products and fish by-products that can be used
include, but are not
limited to, products and by-products derived from tuna, salmon, cod,
whitefish, shrimp, and
the like. Examples of dairy products and dairy by-products that can be used
include, but are
not limited to, products and by-products derived from cheese, milk protein,
whey, and the
like.
[0039] Examples of microbial proteins that can be used include, but are not
limited to,
brewer's yeast, baker's yeast, and the like. Examples of vegetable proteins
that can be used
include, but are not limited to, corn gluten, soy protein, soy flour,
hydrolyzed vegetable
protein (HVP), and the like. Examples of amino acids that can be used include,
but are not
limited to, alanine, glycine, cysteine, and the like. Examples of
carbohydrates that can be
used include, but are not limited to, glucose, xylose, fructose, starch
hydrolysates, and the
like.
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[0040] Other palatability enhancing acids and salts thereof may also be used,
including
pyrophosphoric acid and the sodium, potassium, calcium and magnesium salts
thereof,
phosphoric acid and the sodium, potassium, calcium and magnesium salts
thereof, potassium,
calcium and magnesium tripolyphosphate salts, potassium, calcium and magnesium
hexapolyphosphate salts, organic acids such as citric, tartaric, fumaric,
lactic, acetic, formic
and hexamic acids and the sodium, potassium, calcium and magnesium salts
thereof, and the
like. Other suitable ingredients include vitamin and mineral supplements, such
as, for
example, Vitamin A, dietary calcium supplement salts, and the like, anti-
oxidants and
preservatives, such as, for example, BHA, BHT, TBHQ, tocopherols, rosemary
extract, and
the like, other natural and artificial flavors, such as, for example, dairy
flavor, roast chicken
flavor, and the like.
[0041] The palatability enhancers of the present invention contain from about
0.1% to 99%
by weight of one or more sodium tripolyphosphate salts. Sodium
tripolyphosphate salt levels
between about 5 and about 50% by weight are preferred, with levels between
about 10 and
about 35% by weight more preferred, and levels between about 15 and about 30%
by weight
even more preferred. The palatability enhancers are formulated and applied so
that the one or
more sodium tripolyphosphate salts constitute from about 0.01% to about 5.0%
by weight of
the finished pet food product. Preferably, the palatability enhancers are
formulated so that
the one or more sodium tripolyphosphate salts constitute from about 0.05 to
about 2.0% by
weight of the finished pet food product, more preferably between about 0.1 to
about 1.0% by
weight, and even more preferably between about 0.25 and about 0.75wt%.
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[0042] Among the preferred palatability enhancers according to the present
invention are
palatability enhancers containing from about 5 to about 99 wt.% of one or more
products or
by-products selected from animal products, animal by-products, fish products,
fish by-
products, dairy products and dairy by-products. Preferred products and by-
products that may
be present alone or in combination include animal products and by-products and
more prefer-
ably products and by-products of beef and poultry. Fish products and by-
products are also
preferred. A product or by-product level between about 20 and about 70 wt.% is
preferred.
[0043] Among the same or other preferred palatability enhancers according to
the present
invention are palatability enhancers containing from about 0.01 to about 10
wt.% of one or
more amino acids. Preferred amino acids that may be present alone or in
combination include
glycine, L-alanine, and the like. An amino acid level between about 0.1 and
about 4.0 wt.% is
preferred.
[0044] Among the same or other preferred palatability enhancers according to
the present
invention are palatability enhancers containing from about 5 to about 70 wt.%
of one or more
microbial proteins. Microbial protein levels from about 10 to about 40 wt.%
are preferred.
[0045] Among the same or other preferred palatability enhancers according to
the present
invention are palatability enhancers containing from about 0.01 to about 50
wt.% of one or
more carbohydrates. A carbohydrate level between about 1.0 and about 30 wt.%
is preferred.
[0046] One example of a preferred formulation has a solids content of from
about 10 to
about 40 wt.% of one or more sodium tripolyphosphate salts; from about 30 to
about 60 wt%
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of one or more products or by-products selected from animal products, animal
by-products,
fish products, fish by-products, dairy products and dairy by-products; from
about 25 to about
35 wt.% of one or more sources of microbial proteins; from about 2 to about 4
wt.% of one or
more amino acids; and from about 0.5 to about 60 wt% of one or more
carbohydrates. Dry
formulations have a solids content of about 96 wt%. Liquid formulations may be
diluted to a
total solids content as low as about 30 wt% with water and preferably to a
solids content no
more than about 50 wt% to obtain a viscosity and rheology suitable for spray
application.
The water content may also be supplied by moisture-containing or liquid
components, the
amounts of which are selected by well-known techniques to maintain the solids
content of the
product. Liquid formulations according to the present invention have a pH
between about 2
and about 9. Preferred liquid formulations have a pH between about 2 and about
3.
[0047] One example of a preferred type of liquid palatability enhancer
formulation
combines about 2-40 wt% STPP with about 20-70 wt% of one or more animal by-
products
such as beef hearts or livers, or chicken hearts or livers or one or more fish
by-products such
as fish scraps, or both; about 0.01-5.0 wt% amino acid such as alanine or
lysine; about 0.01-
1.0 wt% preservatives such as sorbic acid and about 0.01-2.0 wt% enzymes such
as protease.
Such a liquid formulation based on about 5-15 wt% STPP is more preferred.
[0048] To make a liquid palatability enhancer formulation according to the
present
invention, for example, commercially available liquid ingredients are combined
in a mixer.
Wet ingredients are ground or emulsified to a slurry and the liquid
ingredients are combined
therewith. A commercially available protease may be added to the slurry to
hydrolyze
proteins, and later inactivated with heat, acid or another method.
Preservatives such as sorbic
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acid can also be added. Water is added to adjust the viscosity and the solids
content of the
slurry to facilitate spray application. In particular, the palatability
enhancer is then topically
applied to a basal food product that preferably has been previously coated
with fat. The wet
palatability enhancer is sprayed onto the product so as to achieve a uniform
coating and
permitted to dry.
[0049] A dry formulation of the palatability enhancer is prepared according to
one
embodiment of the present invention, by combining commercially available dry
ingredients,
including STPP, amino acids, inorganic salts and organic materials in the
desired proportions
in a batch mixer and blending to homogeneity prior to drying.
[0050] According to another dry formulation embodiment, wet and dry
ingredients are
combined by mixing the wet ingredients with all or some of the dry ingredients
in a mixer
until a homogenous mixture is formed. The mixture is dried by evaporation or
lyophilization,
for example, to form a dry, powdery product that is then blended with any
remaining dry
ingredients in a tumbler until a homogeneous mixture is formed. If the STPP is
among the
dry ingredients combined with the wet ingredients prior to drying, the STPP
will dissociate to
form one or more sodium tripolyphosphate salts within a pH range between about
4 and
about 10, and preferably between about 6 and about 8. If the STPP is dry-
blended after the
wet ingredients are dried, it remains as Na5P3010.
[0051] One example of a preferred type of dry palatability enhancer
formulation combines
about 10-30 weight % STPP, about 0.1-4.0 weight % amino acid, such as L-
alanine, about
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35-50 weight % meat, fish or dairy products or by-products, such as dried
chicken liver, and
about 20-50 weight % microbial protein such as brewer's yeast.
[0052] The palatability enhancer also relates to other pet foods and animal
foods in general
without regard to the protein content which typically varies according to
species, breeding
status, and age, among other factors. For example, the palatability enhancer
may be used with
a dry or semi-dry dog food composition for non-breeding, adult dogs, which
requires a
minimum protein content of about 18% by weight on a dry matter basis.
Similarly, the
palatability enhancer may be applied to a dry or semi-dry puppy food having a
minimum
protein content of about 22% by weight on a dry matter basis. The palatability
enhancer may
also be used with other dry and semi-dry foods of varying protein content, and
with foods for
other animals such as livestock and research animals.
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EXAMPLES
[0053] The following examples illustrate the effect of sodium polyphosphate
salts as a
palatability enhancer for food for domestic house cats. The test data was
obtained by a
standard two-bowl test method in which a panel of approximately 20 cats were
each
presented two different food formulations. The food in each bowl was weighed
prior to
presenting it to the cat and, when presented, the bowls were positioned side-
by-side. The
placement of the bowls was reversed daily. Once the food was offered to the
cat, the cat was
allowed free choice in eating from either bowl for up to 16 hours. After the
bowls were
removed, the remaining food from each bowl was individually weighed and the
difference in
weight was recorded as the amount consumed. The amount of food consumed from
each of
the two side-by-side bowls was then compared to determine the Consumption
Ratio (C.R.).
Various dry cat food compositions with the STPP were compared for relative
palatability
with two known palatability-enhancing pyrophosphate salts (TSPP and SAPP).
[0054] In separate tests described in Examples 1 through 8, adult cats were
each offered
products comprising standard dry cat food (Crosswind Industries, Inc., Kansas)
each with or
without a palatability enhancer coating. The tests were performed over a
period of two days
with a sampling of 20 or more cats as test subjects. Dry blend coatings were
prepared dry.
In the spray dried coatings STPP was dissolved in liquid media and permitted
to dissociate at
pH 4 ¨ 10 before spray drying. For the sake of simplicity the coatings are
referred to as spray
dried STPP as compared to the dry-blending of TSPP coating compositions, when,
in fact,
other pyrophosphate and polyphosphate salts were present.
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[0055] The coatings for all samples were comprised of dry poultry heart and
liver (PH&L)
digest prepared in-house by conventional means. Additional ingredients of the
coatings
included SAPP, TSPP and STPP, all of which were obtained from Haifa Chemicals,
Ltd. Of
Israel. All percentages are percentages by weight.
Example 1
[0056] For a base comparison of other enhancers, a flavor enhancer comprising
PH&L digest
dry blended with 30% TSPP was used to coat the Standard Cat Food. This was
compared
with a standard Cat Food coated with a flavor enhancer comprising PH&L digest
dry blended
with 30% SAPP. The consumption by the subjects of the two foods was
essentially the same
showing no real preference between the two.
Example 2
[0057] A flavor enhancer comprising PH&L digest was dry blended with 30% STPP
and
used to coat the Standard Cat Food. This was compared with a standard Cat Food
coated
with a flavor enhancer comprising PH&L digest dry blended with 30% TSPP. The
subject
cats ate TSPP coated and STPP coated foods in a ratio of about 2 to 1.
Example 3
[0058] In three separate trials involving 22, 21 and 24 cats, a flavor
enhancer comprising
PH&L digest was co-spray dried with 30% STPP and used to coat the Standard Cat
Food.
This was compared with a standard Cat Food coated with a dry flavor enhancer
comprising
PH&L digest dry-blended with 30% TSPP. The subject cats showed a significant
preference
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for the STPP, in direct contradiction to Example 2, in which cats showed a
preference for dry
blended TSPP over dry blended STPP.
Example 4
[0059] In a 23 cat trial, a flavor enhancer comprising PH&L digest was dry
blended with
30% STPP and used to coat the Standard Cat Food. This was compared with a
Standard Cat
Food coated with a dry palatability enhancer comprising PH&L digest co-spray
dried with
30% STPP. The subject cats displayed a strong preference for the co-spray
dried STPP in a
ratio of 5 to 1.
Example 5
[00601A flavor enhancer comprising PH&L digest was dry blended with 15% STPP
and
used to coat the Standard Cat Food. This was compared with a standard Cat Food
coated
with a flavor enhancer comprising PH&L digest dry blended with 15% TSPP. The
subject
cats ate TSPP coated and STPP coated in a ratio of about 3 to 1.
Example 6
[0061] In two separate trials involving 22 cats each, a dry flavor enhancer
comprising PH&L
digest was co-spray dried with 15% STPP and used to coat the Standard Cat
Food. This was
compared with a standard Cat Food coated with a flavor enhancer comprising
PH&L digest
dry blended with 15% TSPP. The subject cats showed a greater preference for
the co-spray
dried STPP than in example 5 when dry blended STPP was used.
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Example 7
[0062] A flavor enhancer comprising PH&L digest was co-spray dried with 30%
STPP and
used to coat the Standard Cat Food. This was compared with a standard Cat Food
coated
with a flavor enhancer comprising PH&L digest dry blended with 30% SAPP. In
two
separate tests the subject cats showed a significant preference for the STPP.
Example 8
[0063]A liquid flavor enhancer comprising PH&L digest and 8.5% STPP was spray-
applied
to coat the Standard Cat Food. This was compared with a standard Cat Food
spray-coated
with a liquid flavor enhancer comprising PH&L digest and 8.5% TSPP. The two
products
were at parity in preference testing.
Control
[0064] In two separate tests, a control Standard Cat Food coated only with dry
animal digest
was tested against a test Standard Cat Food coated with the PH&L digest co-
spray dried with
15% and 30% STPP. The subject cats showed a preference for the STPP coated cat
food.
[0065] Table 1 summarizes the results of Examples 1 through 7. "Appl%" refers
to the
amount of palatability enhancer applied as a percentage by weight of the pet
food
composition.
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Table I
Control STPP/SAPP
Example Flavor Appl Flavor Appl Preference Cats/Days
% %
Control 100% dry PH&L 2.0 Co-Spray Dried PH&L 2.35*
1:2.97s 23/2
Digest Digest with 15% STPP
Control 100% dry PH&L 2.0 Co-Spray Dried PH&L 2.85*
1:1.90s 21/2
Digest Digest with 30% STPP
1 Dry blend 70% 2.0 Dry blend 70% PH&L 2.0 1:1.11
20/2
PH&L Digest + Digest with 30% SAPP
30% TSPP
2 Dry blend 70% 2.0 Dry blend 70% PH&L 2.0 2.0s:1
23/2
PH&L Digest + Digest with 30% STPP
30% TSPP
3 Dry blend 70% 2.0 Co-Spray Dried 70% 2.0 1:1.5s
22/2
PH&L Digest + PH&L Digest with 30%
30% TSPP STPP
3 Dry blend 70% 2.0 Co-Spray Dried 70% 0.0 1:1.39s
21/2
PH&L Digest + PH&L Digest with 30%
30% TSPP STPP
3 Dry blend 70% 2.0 Co-Spray Dried 70% 2.0 1:1.37s
24/2
PH&L Digest + PH&L Digest with 30%
30% TSPP STPP
4 Dry blend 70% 2.0 Co-Spray Dried 70% 2.0 1:4.95s
23/2
PH&L Digest + PH&L Digest with 30%
30% STPP STPP
Dry blend 85% 2.0 Dry blend 85% PH&L 2.0 3.03s:1 29/9
PH&L Digest + Digest with 15% STPP
15% TSPP
6 Dry blend 85% 2.0 Co-Spray Dried 85% 2.0 1:1.04
22/2
PH&L Digest + PH&L Digest with 15%
15% TSPP STPP
6 Dry blend 85% 2.0 Co-Spray Dried 85% 2.0 1.28:1
22/2
PH&L Digest + PH&L Digest with 15%
15% TSPP STPP
7 Dry blend 70% 2.0 Co-Spray Dried 70% 2.0 1:1.47s
24/2
PH&L Digest + PH&L Digest with 30%
30% SAPP STPP
7 Dry blend 70% 2.0 Co-Spray Dried 70% 2.0 1:1.96s
22/2
PH&L Digest + PH&L Digest with 30%
30% SAPP STPP
8 Liquid PH&L 5.0 Liquid PH&L Digest 5.0 1.2:1 22/2
Digest + 8.5% + 8.5% STPP
TSPP
* Adjusted to the equivalent 2% digest in the control sample.
5 # Co-spray drying was conducted using the liquid mixture at pH 4-10.
[0066] The foregoing examples thus demonstrate STPP to be a commercially
viable
palatability enhancer for dry and semi-dry pet foods. The palatability
enhancer is
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particularly effective for enhancing the palatability to cats of dry and semi-
dry cat foods.
Further, the use of STPP represents a relatively low added production cost for
pet food
manufacturers. In addition, the improved palatability enhancing effect of STPP
survives a
range of different application systems and different formulations.
[0067] From the preceding description of various embodiments of the present
invention, it
is evident that the objects of the invention are attained. Although the
invention has been
described and illustrated in detail, it is to be clearly understood that the
same is intended by
way of illustration and example only and is not to be taken by way of
limitation. Accordingly,
the scope of the claims should not be limited by the preferred embodiments set
forth
in the description, but should be given the broadest interpretation consistent
with the
description as a whole.
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