Note: Descriptions are shown in the official language in which they were submitted.
This invention relates to pet foods and, in
particular, to a coated pet food of improved appearance and
flavor.
Intermediate moisture food products have been
employed to a substantial extent as pet foods which can be
packaged and stored without special handling to prevent
decomposition. The products are typically formed with
substantial amounts of a protein source such a poultry meal,
fish meal, soybean meal and the like and a cereal product
such as corn or wheat flour and the like which is gelatin-
ized during the manufacture to serve as a binder for the
product. The product can also contain a flavor enhancer
such as meat by-products, e.g., ground fish, poultry or meat
by-products and includes a suitable water binder such as
propylene glycol or sugar to impart a bacteriostatic and
antimycotic action. Typical of such a product is that
described in U.S. Patent 3,852,483 issued December 3, 1974
to Ralston Purina Company.
The products produced in this manner have a gen-
erally porous appearance and it is desirable to coat the
product with materials such as fats or oils to impart a
shine to the products, improving the appearance as well as
the flavor and palatability of the products. Frequently, a
bacteriostat, such a propylene ~lycol, or potassium sorbate
as antimycotic agent are included in the coating to prevent
mold formation on the product.
- Experience in coating of products of the afore-
described type has revealed that the coated products tend to
agglomerate or bunch and do not remain as free flowing
particulate solids.
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lf~337a
This invention comprises a method for the manu-
facture of a free flowing, particulate, intermediate mois-
ture pet food which has a coating of a flavor and/or appear-
ance enhancer. The method comprises the post manufacturing
treatment of an intermediate moisture pet food by the steps
of storing a coated pet food product for a predetermined
time interval sufficient to permit absorption of the coating
into the pores of the product and, thereater, breaking up
agglomerates which are formed during the storage period.
Thereafter the product can be stored and packaged in a
conventional manner and will be found to be free of any
agglomeration tendencies.
More specifically the invention is a method for
the preparation of coated, nonagglomerating, solid particles
of semi-moist animal fGod which comprises: (1) applying a
coating comprising an aqueous emulsion of from 15-50 weight
~er cent of a fat to the surface of a semi-moist granular
product having from 10 to about 40 weight per cent moisture,
; 20 to about 60 weight per cent of a cereal product and from
2 to about 30 weight per cent of a water binder in an amount
sufficient to impart bacteriostasis thereto, the application
of said coating being from 10 to about 35 weight per cent of
said semi-moist granules; (2) storing the coated particles
for a time period of from 1/2 to about 24 hours, sufficient
to reach an equilibrated distribution of said coating
throughout the matrix of said particles; (3) and thereafter
withdrawing said coated product ~rom storage and agitating
the product to breakup clumps and agglomerates formed during
storage; and (4) thereafter packaging the coated particles
in consumer containers.
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llQ;~97~
The lnvention will be described with reference to
the FIGURE which is a schematic flow diagram of the practice
of the invention.
This invention comprises a method for coating of a
semi-moist solid pet food to apply thereto a high content of
preservatives and flavor and appearance enhancers including
gravies and hydrolysates containing fats and oils, propylene
glycol, glycerine, corn syrup and the like.
The semi-moist pet food which is coated in accor-
dance with the invention generally comprises a composition
of ingredients such as cereal products, protein sources,
flavor enhancers and a sufficient quantity of a water binder
to impart bacteriostasis thereto. The moisture content of
such products is usually from about 20 to 40 percent and the
product contains optional quantities of miscellaneous
ingredients such as vitamins and stabilizing additives such
as gums, e.g. carboxymethocellulose, and emulsion stabili-
zing ingredients, etc. The following table will summarize
the ingredients and the broad and preferred concentration
ranges for these ingredients:
TABLE 1
Concentration, Weight Percent
Ingredient Broad Preferred
25 Cereal Product 20-60 35-50
Protein Source 15-35 20-30
Flavor enhancer 3-20 5-12
Water binder 2-30 3-8(a)
(a) pre~erred range for propylene glycol
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1~¢)3S~
TAsLE l (continued)
Concentration, Weight Percent
Ingredient sroad Preferred
16-30~b)
Water(C) 10-40 20-30
Misc. 0-5 1-3
The cereal product which is included in the semi-
moist pet food can be a grain cereal flour such as corn,
rice, wheat, rye, oats, barley, sorgum flour and, of these,
corn and wheat flour are prepared because of their availa-
bility and low cost. As used herein, flour includes coarse
ground products such as meals and farinas as well as finely
ground and bolted products.
The protein source can be a meat or vegetable
source having a high protein content, typically a protein
concentration of from 40 to about 90, preEerably from about
50 to 70, weight percent. Suitable protein sources for this
purpose include fish meal, poultry meal, soybean meal,
cottonseed meal, etc.
Flavor enchancers which can be used include flavor
sources such as various meat byproducts, including liver,
chicken, tuna by-products or fish solubles, the latter being
the concentrate of the cooking water from a fish cannery.
:
(b) preferred range for sugars
~c) total moisture of which about 50-70 percent i9
added water
: ~.
The water binder is commonly any water soluble
monosaccharide or reducing or nonreducing polysaccharides
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and their degradation products. Preferably, sugars of low
molecular weight are employed to provide a substantial
increase in osmotic pressure of the sugar solution, thereby
enhancing the bacteriostatic effect of these additives.
When the composition relys on a sugar as the
principal water binder, the concentration of the sugar is
from about 16 to about 30 weight percent and preferably 20
to about 30 weight percent of the final products.
Another water binding material which can be
employed is a polyhydric alcohol such as glycerol and
sorbitol. When a polyhydric alcohol is employed as the
principal water binder it is used in relatively low concen-
trations, typically from 3 to about 8 weight percent.
The miscellaneous additives of the pet food can
include various vitamins such as vitamins A, D and E,
tocopherols as well as antioxidants for these materials.
The miscellaneous ingredients can also contain a sufficient
amount of a food grade acidulent such as phosphoric, tar-
taric, malic, citric, fumaric acids, etc., to provide a pH
to the product to a value from about 4 to about 6. The
acidulent enhances the bacteriostatic effect of the afore-
mentioned water binder.
Salts and inorganic minerals can also be added to
supply the dietary requirements of these materials, e.g.,
sodium chloride, dicalcium phosphate, zinc oxide, ferrous
sulfate, etc., can be employed as the miscellaneous addi-
tives. The aforementioned products are blended together
with a sufficient quantity of water to provide a moisture
content in the finished product from 20 to about 40 weight
percent. The resulting mixture is thereafter subjected to
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sufficient heating, preferably under pressure, to cause
gelatinization of the starch in the cereal product whereby
the gelatinized starch serves as a binder to consolidate the
mixture into a solid, semi-moist material. Typically the
necessary cooking is performed in an extruder cooker where
the product mixture is subjected to steam temperatures of
from 250-350F and for a period of time from about 3 to
about 20 seconds and is discharged under sufficient pressure
to form a solid extrudate. The extrudate is then chopped
into lengths, typically to form particles of approximately
1/8" diameter and 1/8" long to about 3/4" diameter to 3/4"
long.
The extruded product typically has from 20 to
about 30 weight percent moisture and has a dry, porous,
exterior surface.
Because of the inadequate simulation of meat
products, it is desirable to coat the exterior surface of
the aforedescribed semi-moist pet food product to impart a
shine and texture to the surface that more closely resembles
the appearance of meat products. Additionally, it is
desirable in many instances, to coat the surface of the
product with various anti-mycotic additives such a~ potassium
sorbate in sufficient concentration to inhibit surface
growth of molds. Other materials that can be included in
the coating to enhance the appearance or flavor of a semi-
moist pet food include gravies and broths obtained by
cooking of meat products, hydrosylates obtained by enzymatic
or acid digestion of meat and poultry by-products, corn
syrup, molasses, etc.
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35~
It is preferred to employ a coating composition
having a fat content from 15 to about 40 weight percent,
preEerably from about 20 to about 35 weight percent so that
the coating will impart a high luster or shine to the coated
product. The coating vehicle is typically water which is
present in a concentration from 30 to about 70, preferably
from 40 to about 60, weight percent. A protein source such
as hydrosylate obtained by the hydrolysis of chopped and
washed animal viscera such as fish viscera, e.g., viscera of
tuna, mackerel, perch, bonito, etc.; poultry viscera,
viscera of animals such as goat, lamb, horse, pig, etc. Of
these, poultry viscera is preferred.
The following is a preferred coating composition
for use in the invention:
TABLE 2
Ingredient Concentration, Weight Percent
Poultry fat 15-30
Poultry viscera hydrolysate 15-30
20 Water balance
The aforementioned coating composition can contain
a trace to minor quantity of any of the aforementioned
acidulents, preferably phosphoric acid, to impart stability
to the composition.
The coating is applied to the semi-moist pet food
using any suitable method to attain a uniform distribution
of the coating on the surfaces of the particles. The liquid
emulsion coating can be applied by spraying or by dipping or
tumbling the semi-moist particles into contact with the
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aqueous emulsion coating. Preferably, coating is sprayed
onto the semi-moist pet food particles from a spray header
positioned over a conveyor belt carrying the particles and
the spray is directed downwardly onto the surface of the
particles. One or more baffles can be positioned to turn
the solids as they pass on the conveyor to expose fresh
surfaces for contact by the spray. The amount of the
coating which is applied to the surface of the particles
should be sufficient to effect a substantial elevation of
the moisture content of the product. Typically, extruded
semi-moist product contains approximately 20 weight percent
water, and the coating is applied to raise the moisture
content of this product to approximately 30 weight percent.
This is accomplished by the application of the aforemen-
tioned coatings at concentrations of from 5 to about 35
weight percent, preferably from about 10 to about 25 weight '
percent.
The application of the coating can be made at a
temperature from ambient up to about 190F. Application at
ambient temperature is preferred since less storage time is
required in subsequent treatment as the particles need no
subsequent cooling. The application of the coatin~ at the
aforementioned concentrations will result in semi-moist
particles having a soft, mushy exterior surface.
The resultant product from the coating procedure
thus described is stored for a sufficient length of time for
the surface coating of the high moisture content additive to
absorb into the particles. The length of required storage
time is variable and depends on the amount of coating
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applied, particle size and porosity, temperature of appli-
ca-tion and depth of particle solids in temporary storage;
the latter factors are significant since hot applications
require cooling of the particles to ambient temperatures.
The cooling can be accelerated, if desired, by forced
circulation of a cool air stream throuyh the solids. Ty-
pically the coated product is stored for a period of time of
from 0.25 to about 24 hours, preferably from about ~.5 to
about 10 hours after the application of the coating and the
tumbling treatment.
The required length of storage for any selected
combination of liquid coating and solid product can be
readily determined by coating a representative batch of
solids and storing the coated solids while periodically
sampling and inspecting the solids. The inspection can
comprise fragmenting the solid particles and observing if
the coating has completely penetrated the particles, an
indication of equilibration of the coating distribution.
Alternatively representative samples of the solids can be
agitated to break up any agglomerates and then placed in
sample containers and reinspected after about 2~ hours.
Samples which have an equilibrated distribution of the
coating will be free of any re-agglomeration and the solids
will remain free pouring.
It will be observed upon removal of the coated
product from the aforementioned storage that agglomerates of
the particles have formed. This product is then subjected
to a brief agitation, sufficient to break up clumps and
agglomerates formed during its storage. The agitation can
be achieved by means such as a vibrating conveyor or packaging
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35'7~3
equipment used to dispense metered quantities of the solids
into the consumer package such as cans, boxes, bags and the
like. The resultant product will remain as discrete par-
tic:Les and will easily pour from the package even after
pro:Longed periods of storage.
The following example will illustrate the practice
of the invention and serve to demonstrate results obtainable
therefrom:
Example 1
A dry base pet food is prepared from the following
ingredients:
TABLE 3
Ingredient Weight Percent
15 Meat and meat by-product 15
Poultry by-product meal 20
Ground whole corn 25
Ground wheat 5
Tuna solubles 10
20 Propylene glycol 5
Potassium sorbate 0.1
Artificial food colorings 0.01
Vitamin and mineral supplements 0.75
Anti-oxidant 0.0001
25 Soybean meal 10
Phosphoric acid
Water 8.139
100 . 000
.;
11~397~
The dry base food is prepared by the following
procedure:
1. The poultry by-product meal, whole corn,
wheat and soybean meal are ground through
an Ajacs (trade mark) grinder and screened
through a 20 mesh screen. The meat and
meat by-products are ground through a
3/16" plate on a Weiler (trade mark)
grinder.
2. The ground materials are conveyed into
a mixer and mixed with the tuna soluble,
propylene glycol, potassium sorbate,
artificial food colorings, anti-oxidant,
vitamin and mineral supplements and
water.
3. The admixture is conveyed to the bin
that feeds the cooker-extruder (Wenger
*trade mark). The cooker-extruder has
a 200 hp motor and is operated at a
temperature of about 350F and a
pressure of about 500 psig.
4. The admixture is cooked and extruded
into 3/4" X 3/4" square having a bulk
` density of 24 to 28 pounds per cubic
; 25 foot. The extruded squares are also
called base material.
5. The base material square is cooled to
about 90F on a wire mesh conveyor
using either refrigerated air or at-
mospheric air blown on to the base
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material as it moves from one end
of the conveyor to the other end.
A coating of the following composition is pre-
pared:
TABLE 4
Ingredient Weight Percent
Animal fat 15
Animal by-product digest 14
Phosphoric acid 0^9
Potassium sorbate 0.1
Flavors and spices 0.5
Water 69.5
100.O
The cooled base material is then conveyed into a
tumbling reel and coated with the coating described in Table
4. The amount of the coating depends on the moisture
content of the cooled base material. The ratio of the
, :
coating to the cooled base material ranges from 20:80 to
10:90. The coating is applied hotj about 190F.
The coated base material is then held in storage
and allowed to cool down to room temperature and equilibrate
for a length of time of about three hours. After this lapse
;~ .
;, 25 of time, the product, which has the tendency of its parti-
' ~ cles to stick to each other, is declumped by mechanical
,,
agitatlon and is then packed in cans and/or pouches. The
~inal product has a moisture content of 28 to 35%.
The invention has been described with reference to
a preferred mode of practice. It is not intended that the
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invention be unduly limited by this disclosure. Inst~ad, it
is :intended that the invention be defined by the method
steps and ingredients, and their obvious equivalents, set
forth in the following claims.
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