CA1160500A - Process for preparing a dog food of improved acceptability - Google Patents
Process for preparing a dog food of improved acceptabilityInfo
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- CA1160500A CA1160500A CA000362795A CA362795A CA1160500A CA 1160500 A CA1160500 A CA 1160500A CA 000362795 A CA000362795 A CA 000362795A CA 362795 A CA362795 A CA 362795A CA 1160500 A CA1160500 A CA 1160500A
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Abstract
PROCESS FOR PREPARING A DOG FOOD
OF IMPROVED ACCEPTABILITY
ABSTRACT
The objects of the present invention are to provide a process for preparing a dog food of improved acceptability and the product of that process.
Dog foods, no matter how nutritious, must be palatable for the dogs to receive the proper nutri-tion. This invention provides an improved process for preparing a dog food wherein a proteolytic enzyme selected from the group consisting of ficin, trypsin, papain, pepsin and bromelain, and mixtures of these is used to enzymatically treat a protein-aceous component of the dog food sufficiently for it to release free amino nitrogen such that the total dog food composition will be significantly preferred by dogs. The process is applicable to the pro-duction of dry, intermediate-moisture, and canned dog food products.
OF IMPROVED ACCEPTABILITY
ABSTRACT
The objects of the present invention are to provide a process for preparing a dog food of improved acceptability and the product of that process.
Dog foods, no matter how nutritious, must be palatable for the dogs to receive the proper nutri-tion. This invention provides an improved process for preparing a dog food wherein a proteolytic enzyme selected from the group consisting of ficin, trypsin, papain, pepsin and bromelain, and mixtures of these is used to enzymatically treat a protein-aceous component of the dog food sufficiently for it to release free amino nitrogen such that the total dog food composition will be significantly preferred by dogs. The process is applicable to the pro-duction of dry, intermediate-moisture, and canned dog food products.
Description
~ 1 6~500 DESCRIPTION
PROCESS FOR PREPARING A DOG FOOD
OF IMPROVED ACCEPT~BILITY
Technical Field 05The present invention relates to dog foods, and more particularly to a process for preparing dog foods having increased palatability and the products of these processes.
While the development and production of nutri-tious animal foods is quite well understood and poses few problems to those skilled in the art, there is a continuing problem of making these form-ulations palatable. Accordingly, there is a con-tinuing effort being made to develop processes and formulations which increase the palatability of the animal foods while at the same time maintaining their nut~it~onal value.
The identification of additives and processes for improving the acceptability of dog foods is important industrially from at least two standpoints First, it assures that the dog will consume enough of the food to provide it with the nutrition neces-sary for a healthy existence. Secondly, it enables the production of highly acceptable dog foods em-ploying large amounts of by-products ~rom the human food industry. This helps to maintain the lowest possible cost for human foods by providing a market for the by-products of this industry while at the same time decreasing the pet food industry's reli-ance on the choicer and more select raw materials.
05 Thus, the identification of methods and additives for improving the palatability of pet foods is an important aspect of world food supply.
Background Art The use of additives to increase the acceptance of pet foods is well established in the prior art.
For example, U.S. Patent No. 3,857,968 to G.J Haas et al discloses incorporating into an animal food an effective amount of a palatbility-improving composi-tion comprising fat and protein which has been conditioned by emulsifying the fat and treating the mixture with an enzyme mixture comprising lipase and protease. It is known that free fatty acids and amino acids are liberated by the enzymatic reac-tions; however, the exact reason for the improvement in palatability obtained according to the disclosure of that patent is not fully understood because, while certain of these compounds are known to be flavorful to dogs, others are known to be unaccept-able. Moreover, the level of usage can affect the results.
Amino acids, for example, are known to have widely varying aromas and flavors depending upon their type and concentration. And, there is nothing which indicates their inherent attractiveness to dogs. In U.S. Patent No . 4, 267 ,195, issued May 12, 1981, to J. Boudreau et al discloses L-proline, L-cysteine, L-histidine, and L-lysine are taste active in a dog. However, in testing in food, a commercial dry dog food product, l 16~500 the L-lysine, at the 1% level, and L-proline, at the 1% and 3% levels, did not make the f~od signif-icantly more preferred by dogs. This was explained by the inventors on the basis that these materials 05 could po~sibly be associated with the flavor of raw meat and might be overpowered by the cooked meat flavor of the base dog food.
In published studies of the neural physiology of the cat, these same amino acids were identified as being taste active, while other amino acids, namely L-phenylalanine, L-tyrosine, L-tryptophan, and L-isoleucine were found to exhibit the same groups of neural units that were excited by the other amino acids. These results are set forth by J. Boudreau et al, Chemical Stimulus Determinants of Cat Geniculate Ganglion Chemoresponsive Group II
Unit Discharge, Chemical Senses and Flavor, 1 (1975), pages 495-517; and Cat Neural Taste Responses to Nitrogen Compounds, ACS Symp~sium Series, 26 (1976~;
and White, et al, in Taste Preferences of the cat for Neuro Physiologically Active Compounds, Physiological Psychology, (1975) Vol. 3 (4), pages 405-410.
A general reference to flavorful amino acids is also made in U.S. Patent 3,653,908 to Buck et al, which discloses an intermediate-moisture animal food especially formulated for cats. It is stated there-in that a proteolytic enzyme such as containing tryptic or peptic enzymic activity or mixtures thereof may be added to the disclosed meat-con-taining slurry to effect the appropriate digestion when the slurry is elevated to pasteurization tem-perature. It is stated further that in many appli-cations, a peptic, bromolytic, papaic or tryptic digestion will liberate flavorful amino acids which g16~500 will further impart palatability to the final pro-duct, particularly when employing reducing sugars as the stabilizing solute. The disclosed temperatures of cooking are in excess of 180F ~82C) and the 05 disclosed examples include the presence of reducing sugars. Thus, any improvement in flavor through the use of enzymes is apparantly due to the production of reaction flavors which are found acceptable by cats.
Disclosure of Invention In accordance with the present invention an improved process is provided for preparing a nutri-tionally balanced dog food of increased palata-bility, and ~he product of this process, are pro-vided. The improved process is one for preparingnutritionally balanced dog food comprising protein, fat, carbohydrates, vitamins and minerals wherein at least one proteinaceous component is cooked and shaped into a dog food product, wherein the improve-ment comprises: heating at least a portion of atleast one proteinaceous component at a temperature within the range of from 30C to 70C and reacting it with an enzyme selected from the group consisting of ficin, trypsin, bromelain, pepsin and papain under conditions effective to release free amino nitrogen, and admixing the resulting reaction mixture with the other components of the dog food in an amount effective to provide a significant in-crease in palatability of the dog food to dogs. The product provided by this process is thus signi-ficantly improved over the same dog food formulation not treated in accordance with the process.
The term palatability is broad and encompases all of the various properties of dog foods which are sensed by the consuming animal and determine the 1 1 6~50~
overall acceptability of the food. Among these properties are texture, taste, and aroma. It is believed that the present invention increases palat-ability as a whole, primarily through improving the 05 taste of the food.
The process of the present invention can be employed to improve the palatability of virtually any dog food which contains at least one protein-aceous component. Thus, the process of the present invention can be employed in the preparation of dry, intermediate-moisture, or canned dog foods. The dry dog foods contain less than 15% moisture, and typic-ally have a dry, crunchy texture due to the main-tenance of the moisture below about 9%. The inter-mediate-moisture foods have moisture contents above 15% and less than 50%, and will typically have a soft texture with a moisture content in the range of from 20% to 30%. The canned dog foods will have moisture contents above 50%~ and typically above 70%.
Typical of the dry dog foods are those dis-closed in U.S. Patent No. 3,119,691. Disclosed therein is a dry pet fosd having a gravy-forming coating. The coated pèt food substrate is prepared by admixing proteinaceous and farinaceous components and extruding them under conditions of temperature and pressure to effect expansion o~ the product as it exits the extruder. The preferred dry products are expanded to a degree to incorporate from 25% to 75% by volume of void space. The process of the present invention can be employed to treat at least one of the proteinaceous materials of the food of this type either alone or in combination with one or more of the other proteinaceous or farinaceous components. It is possible to subject the entire v composition to the enzymatic reaction, however, this creates the need for larger reac~or ~acilities and necessitates the use of greater amounts of energy.
Moreover, ~or each additional ingredient added, 05 ~here is also added the possibility tha~ a negative side reaction can occur. Accordingly, it is pre-ferred to treat only so much of the ingredien~s as is necessary to ob~ain the desired increase in palatability.
Typical of the intermediate-moisture dog foods which can be improved in palatability according to the present inven~ion are those diselosed in U. S .
Pate~t No. 3,~02,514 to ~ et al. According to that ~isclosure, proteinaceous meaty materials are lS cooked with stabilizing solute materials in a ~irst stage and ~hen wi~h the other added pet food ~aterialsl which can inelude farinaceous compone~ts, in a second s~age prîor to ~haping and packaging.
An improvement ~n the process described by et al, is disclosed in U~S. Patent No.
4, 212, 894, granted July 15, 1980 to Franzen et al. According to that procedurP, the proteinaceous meaty materials are processed to prepare a pumpable slurry of fresh, uncooked meaty material in a solution containlng suf~icient preser-vative to maintain the meat free from microbial spoilage for a period of at least 5 days, holding the slurry at a tempera~ure effective ~o maintain homogeneity of ~he slurry including dispersed fat until needed for processing and then pasteurizing the meaty materials, shaping it with any additional ingredients, and packaging ~he resulting product.
The prvcess of this invention is particularly well adapted to used with slurries of ~he ~ype 35 discussed in the above-identified Franzen et al 1 1 6~500 U . S . Pat~nt wherein meaty materials are stabilized in slurries which contain sufficient liquid material to maintain them flcwable and pumpable over extended periods and will not usually contain the dry solids 05 other than those needed for limited preservation.
Because the dry ingredients such as non-meat pro-teinaceous materials, farinaceous materials, nutri-tional supplements and ~he like, when used in the final product formulation, need not ~e added to the slurry during storage, the moisture content and the water activity, ~ , of the slurry will remain high.
This makes the slurries good reaction media for the enzymes and provides enhanced processing. Typi-cally, the moisture contents will exceed 50% and will preferably be in the range of from 60 to 75%.
~he AW will be above 0.88 and will preferably be above 0.90.
Exemplary of the canned dog food product which can be processed in accordance with the present invention are those which contain meat balls com-prising at least one proteinaceous component, in a gravy. The me~hod of the invention is carried out in the same manner for dog foods of this type as it would be for those of the dry and intermediate-moisture variety. Accordingly, while it can be seenthat the present invention will be fully disclosed to those of ordinary skill in the art by describing it in detail in the exemplary situation of inter-mediate-moisture products, the teachings are fully applicable to dry and canned products.
While not limited to any particular type of process and in fact not limited for use with foods intended for dogs having particular nutritional requirements, those skilled in the art recognize that nutrition is of paramount importance. It is .~ _,.9 :' l16~500 important that each dog food manufactured be nutri-tionally complete. By nutritionally balancing each individual food in this manner, it is not necessary for the dog owner to balance the quantities of 05 different foods supplied. Thus, the nutritional intake of the dog is assured so long as it intakes a minimum amount of food. Nutritionally balanced foods will contain protein, carbohydrates, fats, vitamins and minerals in amounts established by feeding tests to be sufficient for proper growth and maintenance.
The preparation of intermediate-moisture dog foods has become well established since the inven-tion of Burgess et al in U.S Patent 3,202,514. The present invention provides an improved process for preparing products of this type as well as other meat-containing animal foods employing moisture contents below the minimum 15% and greater than the 30% maximum set forth, and made with different processing conditions and preservation systems than employed therein.
The term 1I flowable" means that the slurry will exhibit a Brookfield viscosity of less than 700,000 centipoises as measured by a model HAT Brookfield viscometer set at 5 RPM using an "F" T-bar spindle on a helipath stand at the process temperature which can be between about 30C and 70~C. Preferably, the viscosity will be below 400,000 centipoises. Slur-ries being flowable according to this definition provide efficient processing including blending and pumping. The reaction according to the process of the present invention increases flowability.
To obtain shelf stability, the final dog food products, as distinguished from the slurries, may be of the intermediate-moisture variety, i.e., from 15%
to 50% moisture, and contain sufficient suitable preservatives in the final product to obtain the requisite shelf stability. Thus 3 the preservatives in the slurry may be supplemented as i5 found nece-05 ssary to obtain the long-term shelf stability re-quired for a commercial product.
Useful "meaty materials", which can be reacted according to the present invention before, during or after being held for periods of time in stabilized pumpable meat slurries, are "meat", "meat meal" and "meat by-products". The term "meat" is understood to apply not only to the flesh of cattle, swine, sheep and goats, but also horses, and other mammals, poultry and fish. The term "meat by-product" is intended to refer to those non-rendered parts of the carcass of slaughtered animals including, but not restricted to, mammals, poultry and the like. Both the terms "meat" and "meat by-products" include such ingredients as are embraced by the terms as defined in the official publication of the Association of American Feed Control Officials, Incorporated.
The term "meat meal" refers to the finely ground, dry, rendered residue from animal tissues, including those dried residues embraced by the term "meat meal" as defined by the aforesaid Association.
Because the meat meals are dried under conditions of mois~ heat, they are already of relatively stable bacterial count and do not markedly increase in bacterial count over significant periods of storage.
Thus, meat meal is not a meaty material for which the slurry storage of Franzen et al would be re-quired, and it is not preferable to add it to the slurry prior to the cooking or pasteurization stage because, among other things, it has a tendency to raise the slurry viscosit~ to an undesirable extent.
- t16059 - îO -According to the present invention, however, it can be added to the meaty slurry earlier where desired to standarize the nutritional content in terms of fat, protein, etc., as may be necessary for process 05 control and to take part in the enzymatic reaction, because the enzymatic reaction reduces the slurry viscosity as to make it more flowable and, there-fore, more pumpable.
The meaty material will preferably consti~ute a significant portion of the product; typically, it will be greater than about 10% by weight and pre-ferably greater than 20%. A usual range for such ingredients in intermediate-moisture dog foods is about 20% to 40%, preferably 25% to 35%, by weight.
Non-meat proteinaceous materials, i.e., protein sources other than meaty materials, are preferably employed to achieve a fully-balanced, nutritional feed ration. Typically, the protein will be derived from a vegetable protein source such as soybean, cottonseed, peanuts and the like. The protein may be present in the form of grits, meal, flour, con-centrate, isolate or the like. Additional protein and flavor may be derived from the meat meal and milk products such as dried buttermilk, dried skimmed milk, whey, casein and other like protein sources, such as eggs or cheese.
The process of the invention can be employed to upgrade the palatability of the final dog food by treating at least one of the proteinaceous compon-ents of the food. It is possible, however, to treatall of the proteinaceous components. In practice, a balance will be struck between the degree of improve-ment of the product by treating any individual component, the cost of reacting the component, and the capability of the process to accomodate the reaction mixture in terms of volume, viscosity or the like for the reaction of certain components.
The preservation of moisture-containing, meaty food from microbial decomposi~ion is dependent upon 05 a variety of factors and mechanisms. There are some generally well accepted preservation mechanisms and systems which have evolved in the art, and any preservation system effective for achieving shelf stability in the final product, which is acceptable to dogs, can be employed in the process of the present invention as far as the requirements of the ultimate product preservation system are concerned.
Thus, for example, the prior art products generally employ sugars, salts, polyhydric alcohols and acids as water binders together with anti-microbials such as sorbic acid and its salts.
The usual preservative mechanisms are generally based on a combination of the above principles and exert a combined stabilizing effect. The disclosure of Bur~ et al in U.S. 3,202,514, Bernatovicz in U.S. 3,985,904 and Harrocks et al in U.S. 4,001,445, are of interest in this regard. The reaction slurries preferred according to the present invention, however, do not contain sufficient amounts of preservatives to maintain longer termshelf stability at the moisture contents involved, but will usually be effective for periods of only up to 15 days or so to provide consistently low bac-terial and mold counts to be used in what could be considered good manufacturing practice.
According to preferred embodiment of the pre-sent invention, the desired proteinaceous materials are slurried with the desired preservative materials and an enzyme selected from the group consisting of ficin, trypsin, bromelain, papain, pepsin and com-binations of these, to fo~ the reaction slurry.
The reaction slurry is brought to a temperature of from 30C to 70C and is held there for a period of time effective to release an amount of free amino 05 nitrogen which will indicate that the palatability of the dog food will be su~ficiently increased.
To prepare the slurry, the meaty materials to be used must be comm nuted as by grinding in one or a series of stages. Typically, the meaty materials, usually stored frozen, are first fed to a coarse grinder, such as a Rietz Extructor,* which chops the material into pieces ranging in size up to as long as 2 to 4 inches in major dimension, and starts thawing the meaty materials. The coarsely chopped material is then fed into a secondary grinder, such as a Hobart* grinder, which continues the thawing process and grinds the meaty material, where the majority of the meat pieces have a maximum diameter of from about 1/8 to about 1/2 inch. This type of grinding is conventional and can be successfully employed according to this invention~ However, the best results according to this invention are achieved when the meaty material is yet further ground, i.e., finely ground, to an extent that the majority of the meaty particles are no larger than 0.050 to 0.100 inch in diameter. This fine grinding procedure can be performed in Urschel Comitrol*cr Seydelmann* bowl chopper. To aid the grinding and establish the limited preservation system, the liquid materials in the composition are preferably mixed with the meaty material. Typical of the liquid materials which can be employed are poly-hydric alcohols and corn syrups. Typically, the liquids added will be present at a level of at least 10% of the weight of the meaty material * Trade mark ~D
1 ~ 605~0 After grinding~ the meaty material is ready for reaction and is preferably mixed with any remaining liquid ingredients of the total formulation, i.e., the dog food matrix, as well as other protein mater-05 ials that are desired to be reacted. To accomplishthis, the additional ingredients can be mixed prior to or upon entry into the reaction vessel. Thus, in one embodiment, the meat and preservative solution is mixed and then fed into a reaction tank; and in another embodiment, these ingredients are mixed in the tank.
The pH and temperature of the slurry are both important parameters for the accomplishment of the enz~matic reaction as well as for a number of other reasons. Thus, in addition to its influence on the reaction, the pH of the system is important to the maintenance of microbial stability, and the pump-ability of the slurry. To obtain optimum results in terms of these properties yet maintain a relatively non-corrosive material which does not have to be adjusted in pH radically during final production preparation, the pH will be within the range of from 4.0 to 8.0, preferably from 4.8 to 5.5. If the pH
is substantially above or below the isoelectric point of the protein material in the slurry, the slurry will not be as easily pumpable at the pre-ferred moisture contents.
The temperature has an important effect on the reaction rate and the slurry viscosity. Where the reaction ~emperature drops below about 30C, the reaction rate decreases and the fat in the slurry tends to solidify, coming out of dispersion. This solid fat will interfere with stirring and pumping as well as render the slurry non-homogeneous.
Reaction slurry temperatures will therefore be within the range of from 30C to 70C and will preferably be from 40C to 60C. Most preferably, the temperature is maintained near the upper end of this range for reaction, but is then briefly raised 05 to a temperature effective to inactivate the enzymes, and is then brought back to the lowe~ part of ~he range for continued storage.
The reaction slurry is preferably brou~ht to the effective reaction ~onditions prior to adding the enzymes; however, the enzyme can be added first.
It has been determined, according to the present invention, that the exact amount of enzyme as a percentage of the reaction mixture is not a con-trolling factor. What is important, is that there be sufficient enzymatic acti~7ity at the desired Feaction conditions to effect a sufficient release of ~ree amino nitrogen such that when the reaction mixture is admixed with the remainder of the dog food ingredients, the overall palatability of the composition will be improved as compared to a com-position not treated in this manner. While tests have not indicated an absolute value for free amino nitrogen concentration which will provide this palatability increase, it has been determined that reactions which release sufficient amino nitrogen to at least about one and one half and more preferably about double the starting concentration, will be effective to increase palatability in dog food formulations wherein the treated slurry comprise at least about 10%, and preferably at least about 30%
of the weight of the final dog food formulation.
The free amino nitrogen ~ninhydrin) is determined by the method published in JAOAC:806 (1977). Even more preferably, the reaction will liberate sufficient free amino nitrogen to bring the level of it up to ~ 16~50 about two and one half times that present in the slurry prior to processing.
Testing has shown that it is not necessary to employ any particular concentration or activity of 05 enzyme to obtain a desired result of liberating ~ree amino nitrogen. While any of the enzymes selected from the group consisting of ficin, trypsin, papain, pepsin, and bromelain can be employed according to the present invention with good results, it is presently preferred to employ bromelain. It is difficult to further define the enzyme activity beyond that which the assay reports. The following is a list of enzymes employed and their corres-ponding activity as defined by various suppliers.
Different amounts of the enzymes may be used de-pending on concentration and purity of the enzyme.
This is used to further teach those skilled in the art how to make and use the claimed invention and in no way is meant to limit the scope or definition of the invention.
ENZYMES
PaPain:
One unit will hydrolyze one micro-mole of Alpha-N-Benzoyl-L-Arginine Ethyl Ester (BAEE) per minute at pH 6.2 at 25C.
Man~facturer Activity: 1.6-2.8 BAEE units per mg.
solid Bromelain:
One unit will hydrolyze 1.0 mg. of amino nitro-gen from ~elatin in 20 minutes at pH 4.5 at 45C.
Manufacturer Activity: 2000-4000 units per mg.
protein (BIURET).
~1605~0 Ficin:
One unit will produce a delta-O~280 of 1.0 per minute at pH 7.0 at 37C when measuring trichlor-acetic acid soluble products from casein in a final 05 volume of 10 ml.
Manufacturer Activity: 0.2-0.8 units/mg.
Trypsin:
One BAEE unit = delta-OD253 of 0.001 per minute with Alpha-N-Benzoyl-L-Arginine Ethyl Ester (BAEE) as substrate at pH 7.6 at 25C.
Manufacturer Activity: 1000-1500 BAEE units per mg.
Pepsin:
One unit will produce a delta-A280 of 0.001 per minute of pH 2.0 at 37C, measured as trichloracetic acid soluble products, using hemoglobin as sub-strate.
Manufacturer Activity: 700-1000 units per mg.
protein.
The reaction mixture can be held after process-ing for the period of time necessary for inventory control and then pumped directly to the process for admixture with the remaining pet food ingredients.
Among these ingredients are the dry mateials, such as farinaceous materials, vegetable protein mater-ials, nutrients, further preservatives, and thelike. After mixing, or concurrent therewith, the dog food formulation is then pasteurized.
The preferred reaction slurries do not contain all of the preservation materials employed in the final product. The slurry need be preserved only for the short period of time from receipt into the plant to manufacture into the final pet food material.
~ 16~5~0 This initial period of storage will typically range from about one day up to about five days. To pro-vide a practical degree of safety with cost effect-iveness, however, it is preferred to maintain the 05 meaty materials without refrigeration or freezing for a period of up to at least ten days and pre-ferably a few days longer, say up to fifteen days, to guard against severe inventory problems which may occur despite the best planning.
Intermediate-moisture food preservation systems typically employ preservative materials which are antimicrobial and also materials which control the amount of moisture in a system available as a growth medium. The expression typically employed for defining the amount of water available to support microbial growth is the water activity, AW of a product. The ~ is equal to the vapor pressure of water in the system divided by the vapor pressure of pure water at the same temperature. Theoretically, the ~ of a given system can be lowered to such a degree that the water is not sufficiently available to support any microbial growth. However, to achieve the proper taste and texture for inter-mediate-moisture dog food products, it is not pos-sible as a practical matter to obtain these lowvalues. Where the ~ of the system is not lowered to the absolute point below which organisms will not grow, anti-microbials are also added. Typically, these anti-microbial agents are added to control mold growth which is not sufficiently retarded at the ~ values involved.
~ he water activity of the reaction slurries of the present invention will preferably not be at the low level necessary for long term preservation, and in fact, will preferably be above 0.88 as a function 1 ~ 6~5~0 of the high moisture content necessary to maintain slurry pumpability without the need for large amounts of liquid plasticising additives. Because the major portion of the dry raw materials is not in 05 the slurry, the moisture content and ~ will be higher than would be necessary to have a shelf-stable product.
The final intermediate-moisture products, as distinguished from the reaction slurries, have water binding ingredients dispersed throughout in amounts sufficient to achieve ~ values of below about 0.93;
and further preferably have in contact therewith an anit-microbial agent. The level of the water bind-ing ingredients and anti-microbial agent is suf-ficient to keep the product resistant to microbialgrowth and decomposition when packaged in a substan-tially moisture-impermeable packaging material. The level of anti-microbial agents and ~ lowering ingredients will be balanced to achieve stability at the given moisture content. For example, it may be necessary to employ only a minor amount of anti-microbial agent where the ~ of a given inter-mediate-moisture system is at a level nearly pre-cluding all growth. Conversely, larger amounts of anti-microbial agents may be needed in a moisture containing system wherein the ~ is closer to 0.93.
It is preferred to employ .evels of sorbate salt or sorbic acid anti-microbial~ effective to prevent mycotic or bacterial growth.
Use~ul as water binding ingredients are any of the edible materials which have the ability to tie up water to such an extent that it is no longer usable for microbial growth and propagation. Exem-plary of this group of materials are sugars, polyhy-dric alcohols, mixtures thereof, and mixtures of 1 1 6~5~
alkali metal or alkaline earth salts with sugar and/or one or more polyhydric alcohols.
The polyhydric alcohols useful as liquid pre-servatives for use in the slurries are pre~erably 05 polyhydric alochols having from 3 to 7 carbon atoms.
Preferred dihydric alcohols are 1,2-propanediol and 1,3-butanediol. Glycerine, a trihydric alcohol, is a very effective water binder and may be alone or in combination with a dihydric alcohol. Other useful polyhydric alcohols include tetritols, such as erythritol or the threitols; pentitols, such as ribitol or xylitol; hexitols such as sorbitol or manitol; and heptitols, such as perseitol or volem-itol.
Sugars usef~l as water binding agents include the reducing and non-reducing water soluble mono-and polysaccharides; e.g., pentoses such as xylose and arbinose; hexoses such as glucose, fructose or galactose; and disacharides such as lactose, sucrose and maltose. To be effective as a bacteriostatic agent, the sugars are preferably water soluble and of such a low molecular weight as to be effective in increasing the osmotic pressure of the aqueous system in which it is dissolved. Preferred sugars are sucrose, dextrose and highly converted corn syrups, especially high fructose corn syrups.
Various alkali metal and alkaline earth metal halide salts are also effective water binding agents Preferred salts are sodium chloride and calcium chloride.
The provision of an acid medium by the addition of acid or acid salts will also aid in preventing microbial decomposition. Preferred acids include phosphoric, citric, malic, fumaric, hydrochloric, sulfuric, lactic, acetic, adipic and the other known 1 ~ 6~5~0 non-toxic acids. Phosphoric acid is the most pre-ferred due to its use as a source of phosphorous.
Similarly, the provision of an alkaline environment can aid in preparation. Preferred alkaline ma~er-05 ials are calcium hydroxide and sodium hydroxide.
The preferred solutions for adding to thereaction slurries of meaty materials according to the present invention will contain a polyhydric alcohol, such as propylene glycol, and an anti-microbial such as potassium sorbate. The reactionslurry will thus have sufficient flowability for processing as well as have suitable stability for holding in the reaction tank for extended periods after reaction. The most preferred systems will also contain other water binders in the form of salts and sugars and contain acid or alkaline materials to modify the pH from near neutral to a value less conducive to microbiological growth. It is preferred to adjust the pH of the final product to a level between 5 and 8, where dogs find the product palatable. This can be done by overt addi-tion of a neutral:izing medium or by the natural buffering capacity of the dry ingredients.
A particularly preferred system contains pro-pylene glycol, potassium sorbate, sodium chlorideand phosphoric acid to adjust the slurry pH to a value of from 4.0 to 8Ø The optimum results have thus far been achie~ed using pH values of about 5.5.
At pH values about this level, both the enzymatic reaction during the reaction period and preservation of both the slurry and the final product are aided.
Moreover, the slurry viscosity during storage is suitably low due to maintenance of the pH near the system isoelectric point. Mixing the additional dog food ingredients will adjust the pH of the final ~ 5~0 product to within the preferred range.
After admixing all the remaining dog food ingredients, the complete formulation is preferably pasteurized. The pasteurization can be performed 05 either continuously or batchwise, and heating can be either direct by injection of steam or indirect by employing a heated jacket on the cooker. Continuous operation with direct steam injection in an extruder-cooker is preferred. Typical of the continuous cooking devices which can be employed are an ~nder-son extruder-cooker and a Wenger mixer-conditioner.
For batchwise pasteurization, a simple kettle fitted with a stirring device adequate to keep the matrix material under constant agitation, can be employed. Heat can be supplied by steam supplied to a jacket around the kettle.
Upon discharge from the cooker, the dog food matrix is preferably cooked prior to shaping into the desired final product form. It is possible with the continuous pasteurization to employ a cooling jacket around the final stage of the extruder-cooker to enable shaping to the desired final size directly upon exiting the extruder. Typically, however, the matrix material is discharged into a separate cool-ing device which may be of any conventional con-struction, for example, a wire mesh belt, a per-forated deck, or a jet zone cooler~ wherein cooled air at temperature of about 20C is directed across the matrix material. To enable optimum shaping and handling characteristics, the matrix material is preferably cooled to a temperature of below 30C, and preferably to about 25C. The final shaping and packaging of the product from this point on can be done in conventional manner, for example, usin~ the teachings of the Burgess et al patent, U.S.
3,20~,514, mentioned above.
Best Mode For Carry~ Out The Invention The following Examples are for the purpose of further illustrating the present invention and are not to be taken as limiting in any regard. Unless 05 otherwise indicated, all parts and percentages are by weight.
Example I
According to this example, the preparation of an intermediate-moisture dog food according to the invention described wherein a portion of the meaty materials were reacted with bromelain to improve the palatability of the food.
In preparing the food, the following ingre-dients were finely chopped and slurried in accor-dance with the procedures set forth in U . S . Patent 4,212,894, granted July 15, 1980, to Franzen et al and assigned to the assignee of the present invention:
In~redient Parts 20 Beef Tripe and Trimmings 36.5 Soy Grits 32.6 Sucrose 17.4 Propylene Clycol 5.2 Corn Syrup 3.0 Phosphoric Acid (85%) 0.26 Soy Protein Isolate 1.9 Dried Whey 1.0 Iodized Salt 1.25 Monocalcium Phosphate 0.96 30 Calcium Carbonate 1.0 Soybean Hulls 2.2 Sodium Carboxymethylcellulose 0.5 Mono- and Di-Glyceride Emulsifier 0.5 Flavor, Color, Vitamins and Minerals .8 35 Potassium Sorbate 0.17 1 t 6~50 Of these, the meaty materials (beef tripe and trimmings), propylene glycol, potassium sorbate, sodium chloride and phosphoric acid were mixed to form a slurry. The meaty materials were first 05 ground frozen through a 0.95 cm hole die on a Hobart grinder. The ground meats were then placed in a Baker-Perkins Sigma*bladed mixer and the other noted materials were added to form a meaty slurry. The slurry was then divided into two portions for use in preparing two dog food formulations, identified as test (Tl) and control (Cl). Portion Tl was treated by heating it to 60C, admixing therewith 0.1% Miles Bromelain llOO*based upon the weight of the slurry, (available from Miles Laboratories), maintaining the temperature at that level for 1 hour, and then sharply raising the temperature to about 75C to inactivate the enzyme. The Miles Bromelain 1100 had a proteolytic activity of 1100 bromelain tyrosine units (BTU's) as measured by the quantity of enzyme needed to produce one micromole of tryosine per minute under conditions of the assay. The free amino nitrogen of portion Tl was about twice that of portion Cl.
The dry ingredients were separately blended and then mixed in a Day Cooker*equipped with a sigma arm mixer. Portions Tl and Cl were then heated at about 82C for about 15 minutes to provide the necessary heating for pasteurization. Upon exiting the cooker, the pasteurized products Tl and Cl were cooled by air at about 20C to a temperature of 25C. The cooled formulations were then shaped in a Bonno~ extruder fitted with a die plate having 0.4 cm diameter holes. The formed products were then heat sealed in polypropylene film bags.
The separate samples prepared in this manner, * Trade Mark ~ .
dog foods T1 and sample Cl, were fed to a panel of 120 dogs for 1 day. The do~ food T1 was signi-ficantly preferred to C1.
Example II
05 The procedure for the control of Example I was repeated to prepare a control sample C2, but this time a test sample, T2, was prepared using a mixture of soy grits, water and tallow to replace the meat portion of the control, C2, formula. According to the invention, a mixture of 36.2 parts soy grits and 42.9 parts of water was enzymatically treated with 0.08 parts of papain for 15 minutes at 40C at the end of the treatment, 20.8 parts of tallow were added to the mixture and the remaining formula ingredients added and processed u3ing the procedure of Example I. A second control, Cs was prepared in the same manor as T2 but without the enzymatic treatment of the soy. For example T2 and Cs the soy, water, tallow mixture was formulated to contain the same protein, fat and moisture levels as the meat slurry. Here T2 was significantly preferred to both C2 and Cs. The enzyme used was Type I crude papain obtained from the Sigma Chemical Co.
Example III
This example illustrates the preparation and testing of a dry dog food improved according to the present invention. A control sample (C3) and a test sample (T3~ were prepared from the following ingredients:
Ingredient Parts Whole Ground Corn 37.8 Hominy Feed 3.6 Wheat Middlings 18.2 1~6~500 - ~5 -Soybean Oil Meal 23.1 Meat Meal 14.8 Vitamins, Minerals, Salt, Color, Etc. 2.5 05 The ingredients were processed in the same manner as Example I to produce samples C3 and T3, except that in preparing sample T3, the soybean oil meal and meat meal portions of the formula were treated with a protease enzyme by admixing Miles Bromelain 1100*
to a level of 0.1% based on the weight of the pro-teinaceous material of a 1:1 slurry of the protein-aceous ingredients and water and heating to 60C for four hours. The treated slurry was then mixed with the remaining ingredients, run through an Anderson *
cooker/ expander, and dried to about 9% moisture.
For the C3 sample, the ingredients were mixed and processed through the Anderson cooker/extruder at the same moisture/ temperature conditions and dried to about 9% moisture. The two samples were fed to dogs for two days using standard paired com-parison testing procedures. The T3 sample was ~igniicantly preferred to the C3 sample by the dogs.
This example illustrates the preparation of an intermediate-moisture dog food according to the present invention. A test sample T4 was prepared from the following ingredients.
Ingredient Parts Wheat Flour 21.2 Soybean Oil Meal 15.6 Meat Meal 15.0 Whole Ground Corn 14.5 Isomerose~Corn syrup blend 7.0 * Trade mark C
t t 6~00 Tallow 4,0 Propylene Glycol 4.0 Salt 1.0 Soy Oil 1.0 05 Potassium Sorbate 0.15 Vitamins/Minerals/color .13 Miles Bromelain 1100 0.005 Water 16.5 A slurry was prepared by mixing 2/3 of the meat with water at a 1:1 ratio. The slurry was heated to 60C. The Miles Bromolain 1100 was added and the slurry held at 60C for 30 minutes under constant agitation. At the end of the hold time, the temper-ature of the slurry was raised to 82C and held for minutes to inactivate the enzyme. The liquid ingredients, mainly, the soy oil, propylene glycol, and the Isomerose/corn syrup blend, were added to the meat meal slurry. The remaining dry ingredients were separately blended and then admixed with the slurry. The resulting mixture was processed through an Anderson cooker/expander with the water added into the cooker/expander. The resulting expanded product was cooled on a wire mesh screen using ambient air, and surface coated with tallow.
The test sample was fed to 60 dogs for 2 days versus a commercial intermediate-moisture product (C4) using a standard paired comparision testing procedure. No difference was seen between the ~wo samples. A second con~rol sample (Cs) prepared using the same formula and process but without the enzyme treatment was significantly less preferred when fed versus the commercial intermediate-moisture product C4.
11~$500 Example V
Samples T5 and T6 were prepared in accordance with the procedure outlined in Example 1 in which a meat slurry was treated with ~he enzyme trypsin for 05 1 hour at 40C. The levels of trypsin used were O.01% and 0.1% based on the meat slurry. When fed versus an untreated control, both trypsin treated samples T5 and T6 were significantly preferred by the dogs.
Example VI
A sample was prepared according to the pro-cedure outlined in Example l in which a meat slurry was treated with the enzyme ficin for one hollr at 40C. The level of enzyme used was 0.1% based on the meat slurry. When fed against an untreated control the test sample was significantly preferred by dogs.
Example VII
A test sample was prepared in accordance with the procedures outlined in Example 1 in which a meat slurry was treated with the enzyme pepsin for one hour at 40C. The level of enzyme used was 0.1%
based on the meat slurry. When fed against an untreated control the test sample was significantly ~5 preferred by the dogs.
Example VIII
According to this Example, the preparation of a dry dog food is accomplished according to the invention wherein a portion ~f the proteinacious material is reacted with papain to improve the palatability of the pet food.
In preparing the food, T~, the following ingre-dients w~re processed in the same manner as Example III. The meat meal portion of the formula was treated with papain to a level of 0.5% based on the 05 weight of the proteinaceous material of a 2:5 slurry of the proteinaceous ingredient and water and heat-ing to 55C for three hours. The treated slurry was then mixed with the remaining ingredients, run through an Anderson cooker/expander and dried to about 9% moisture. Control sample, C8, used the same ingredients except instead of enzyme treated meat meal, poultry meal was substituted. The ingre-dients were mixed and processed through the Anderson cooker/extruder at the same moisture/ temperature condi~ions and dried to about 9% moisture. The two samples were fed to dogs using standard paired test-ing procedures. The T8 sample and the control C8 sample were equal in preference levels. Thus one skilled in the art will recognize that papain treat-ment of meat meal upgrades it to the preferencelevel of poultry meal.
Ingredient Parts Whole Ground Corn 37.8 Hominy Feed 3.6 Wheat Middlings 18.2 Soybean Oil Meal 23.1 Meat Meal 14.8 Vitamins, Ninerals, Salt, Color, Etc. 2.5 The above description is for the purpose of teaching those skilled in the art how to practice ~he present invention and is not intended to recite all the possible modifica~ions and variations there-116~00 of which will become apparent to the skilled worker upon reading. It is intended, however, that all such modifications and variations be included within the scope of the invention which is defined by the 05 following claims.
PROCESS FOR PREPARING A DOG FOOD
OF IMPROVED ACCEPT~BILITY
Technical Field 05The present invention relates to dog foods, and more particularly to a process for preparing dog foods having increased palatability and the products of these processes.
While the development and production of nutri-tious animal foods is quite well understood and poses few problems to those skilled in the art, there is a continuing problem of making these form-ulations palatable. Accordingly, there is a con-tinuing effort being made to develop processes and formulations which increase the palatability of the animal foods while at the same time maintaining their nut~it~onal value.
The identification of additives and processes for improving the acceptability of dog foods is important industrially from at least two standpoints First, it assures that the dog will consume enough of the food to provide it with the nutrition neces-sary for a healthy existence. Secondly, it enables the production of highly acceptable dog foods em-ploying large amounts of by-products ~rom the human food industry. This helps to maintain the lowest possible cost for human foods by providing a market for the by-products of this industry while at the same time decreasing the pet food industry's reli-ance on the choicer and more select raw materials.
05 Thus, the identification of methods and additives for improving the palatability of pet foods is an important aspect of world food supply.
Background Art The use of additives to increase the acceptance of pet foods is well established in the prior art.
For example, U.S. Patent No. 3,857,968 to G.J Haas et al discloses incorporating into an animal food an effective amount of a palatbility-improving composi-tion comprising fat and protein which has been conditioned by emulsifying the fat and treating the mixture with an enzyme mixture comprising lipase and protease. It is known that free fatty acids and amino acids are liberated by the enzymatic reac-tions; however, the exact reason for the improvement in palatability obtained according to the disclosure of that patent is not fully understood because, while certain of these compounds are known to be flavorful to dogs, others are known to be unaccept-able. Moreover, the level of usage can affect the results.
Amino acids, for example, are known to have widely varying aromas and flavors depending upon their type and concentration. And, there is nothing which indicates their inherent attractiveness to dogs. In U.S. Patent No . 4, 267 ,195, issued May 12, 1981, to J. Boudreau et al discloses L-proline, L-cysteine, L-histidine, and L-lysine are taste active in a dog. However, in testing in food, a commercial dry dog food product, l 16~500 the L-lysine, at the 1% level, and L-proline, at the 1% and 3% levels, did not make the f~od signif-icantly more preferred by dogs. This was explained by the inventors on the basis that these materials 05 could po~sibly be associated with the flavor of raw meat and might be overpowered by the cooked meat flavor of the base dog food.
In published studies of the neural physiology of the cat, these same amino acids were identified as being taste active, while other amino acids, namely L-phenylalanine, L-tyrosine, L-tryptophan, and L-isoleucine were found to exhibit the same groups of neural units that were excited by the other amino acids. These results are set forth by J. Boudreau et al, Chemical Stimulus Determinants of Cat Geniculate Ganglion Chemoresponsive Group II
Unit Discharge, Chemical Senses and Flavor, 1 (1975), pages 495-517; and Cat Neural Taste Responses to Nitrogen Compounds, ACS Symp~sium Series, 26 (1976~;
and White, et al, in Taste Preferences of the cat for Neuro Physiologically Active Compounds, Physiological Psychology, (1975) Vol. 3 (4), pages 405-410.
A general reference to flavorful amino acids is also made in U.S. Patent 3,653,908 to Buck et al, which discloses an intermediate-moisture animal food especially formulated for cats. It is stated there-in that a proteolytic enzyme such as containing tryptic or peptic enzymic activity or mixtures thereof may be added to the disclosed meat-con-taining slurry to effect the appropriate digestion when the slurry is elevated to pasteurization tem-perature. It is stated further that in many appli-cations, a peptic, bromolytic, papaic or tryptic digestion will liberate flavorful amino acids which g16~500 will further impart palatability to the final pro-duct, particularly when employing reducing sugars as the stabilizing solute. The disclosed temperatures of cooking are in excess of 180F ~82C) and the 05 disclosed examples include the presence of reducing sugars. Thus, any improvement in flavor through the use of enzymes is apparantly due to the production of reaction flavors which are found acceptable by cats.
Disclosure of Invention In accordance with the present invention an improved process is provided for preparing a nutri-tionally balanced dog food of increased palata-bility, and ~he product of this process, are pro-vided. The improved process is one for preparingnutritionally balanced dog food comprising protein, fat, carbohydrates, vitamins and minerals wherein at least one proteinaceous component is cooked and shaped into a dog food product, wherein the improve-ment comprises: heating at least a portion of atleast one proteinaceous component at a temperature within the range of from 30C to 70C and reacting it with an enzyme selected from the group consisting of ficin, trypsin, bromelain, pepsin and papain under conditions effective to release free amino nitrogen, and admixing the resulting reaction mixture with the other components of the dog food in an amount effective to provide a significant in-crease in palatability of the dog food to dogs. The product provided by this process is thus signi-ficantly improved over the same dog food formulation not treated in accordance with the process.
The term palatability is broad and encompases all of the various properties of dog foods which are sensed by the consuming animal and determine the 1 1 6~50~
overall acceptability of the food. Among these properties are texture, taste, and aroma. It is believed that the present invention increases palat-ability as a whole, primarily through improving the 05 taste of the food.
The process of the present invention can be employed to improve the palatability of virtually any dog food which contains at least one protein-aceous component. Thus, the process of the present invention can be employed in the preparation of dry, intermediate-moisture, or canned dog foods. The dry dog foods contain less than 15% moisture, and typic-ally have a dry, crunchy texture due to the main-tenance of the moisture below about 9%. The inter-mediate-moisture foods have moisture contents above 15% and less than 50%, and will typically have a soft texture with a moisture content in the range of from 20% to 30%. The canned dog foods will have moisture contents above 50%~ and typically above 70%.
Typical of the dry dog foods are those dis-closed in U.S. Patent No. 3,119,691. Disclosed therein is a dry pet fosd having a gravy-forming coating. The coated pèt food substrate is prepared by admixing proteinaceous and farinaceous components and extruding them under conditions of temperature and pressure to effect expansion o~ the product as it exits the extruder. The preferred dry products are expanded to a degree to incorporate from 25% to 75% by volume of void space. The process of the present invention can be employed to treat at least one of the proteinaceous materials of the food of this type either alone or in combination with one or more of the other proteinaceous or farinaceous components. It is possible to subject the entire v composition to the enzymatic reaction, however, this creates the need for larger reac~or ~acilities and necessitates the use of greater amounts of energy.
Moreover, ~or each additional ingredient added, 05 ~here is also added the possibility tha~ a negative side reaction can occur. Accordingly, it is pre-ferred to treat only so much of the ingredien~s as is necessary to ob~ain the desired increase in palatability.
Typical of the intermediate-moisture dog foods which can be improved in palatability according to the present inven~ion are those diselosed in U. S .
Pate~t No. 3,~02,514 to ~ et al. According to that ~isclosure, proteinaceous meaty materials are lS cooked with stabilizing solute materials in a ~irst stage and ~hen wi~h the other added pet food ~aterialsl which can inelude farinaceous compone~ts, in a second s~age prîor to ~haping and packaging.
An improvement ~n the process described by et al, is disclosed in U~S. Patent No.
4, 212, 894, granted July 15, 1980 to Franzen et al. According to that procedurP, the proteinaceous meaty materials are processed to prepare a pumpable slurry of fresh, uncooked meaty material in a solution containlng suf~icient preser-vative to maintain the meat free from microbial spoilage for a period of at least 5 days, holding the slurry at a tempera~ure effective ~o maintain homogeneity of ~he slurry including dispersed fat until needed for processing and then pasteurizing the meaty materials, shaping it with any additional ingredients, and packaging ~he resulting product.
The prvcess of this invention is particularly well adapted to used with slurries of ~he ~ype 35 discussed in the above-identified Franzen et al 1 1 6~500 U . S . Pat~nt wherein meaty materials are stabilized in slurries which contain sufficient liquid material to maintain them flcwable and pumpable over extended periods and will not usually contain the dry solids 05 other than those needed for limited preservation.
Because the dry ingredients such as non-meat pro-teinaceous materials, farinaceous materials, nutri-tional supplements and ~he like, when used in the final product formulation, need not ~e added to the slurry during storage, the moisture content and the water activity, ~ , of the slurry will remain high.
This makes the slurries good reaction media for the enzymes and provides enhanced processing. Typi-cally, the moisture contents will exceed 50% and will preferably be in the range of from 60 to 75%.
~he AW will be above 0.88 and will preferably be above 0.90.
Exemplary of the canned dog food product which can be processed in accordance with the present invention are those which contain meat balls com-prising at least one proteinaceous component, in a gravy. The me~hod of the invention is carried out in the same manner for dog foods of this type as it would be for those of the dry and intermediate-moisture variety. Accordingly, while it can be seenthat the present invention will be fully disclosed to those of ordinary skill in the art by describing it in detail in the exemplary situation of inter-mediate-moisture products, the teachings are fully applicable to dry and canned products.
While not limited to any particular type of process and in fact not limited for use with foods intended for dogs having particular nutritional requirements, those skilled in the art recognize that nutrition is of paramount importance. It is .~ _,.9 :' l16~500 important that each dog food manufactured be nutri-tionally complete. By nutritionally balancing each individual food in this manner, it is not necessary for the dog owner to balance the quantities of 05 different foods supplied. Thus, the nutritional intake of the dog is assured so long as it intakes a minimum amount of food. Nutritionally balanced foods will contain protein, carbohydrates, fats, vitamins and minerals in amounts established by feeding tests to be sufficient for proper growth and maintenance.
The preparation of intermediate-moisture dog foods has become well established since the inven-tion of Burgess et al in U.S Patent 3,202,514. The present invention provides an improved process for preparing products of this type as well as other meat-containing animal foods employing moisture contents below the minimum 15% and greater than the 30% maximum set forth, and made with different processing conditions and preservation systems than employed therein.
The term 1I flowable" means that the slurry will exhibit a Brookfield viscosity of less than 700,000 centipoises as measured by a model HAT Brookfield viscometer set at 5 RPM using an "F" T-bar spindle on a helipath stand at the process temperature which can be between about 30C and 70~C. Preferably, the viscosity will be below 400,000 centipoises. Slur-ries being flowable according to this definition provide efficient processing including blending and pumping. The reaction according to the process of the present invention increases flowability.
To obtain shelf stability, the final dog food products, as distinguished from the slurries, may be of the intermediate-moisture variety, i.e., from 15%
to 50% moisture, and contain sufficient suitable preservatives in the final product to obtain the requisite shelf stability. Thus 3 the preservatives in the slurry may be supplemented as i5 found nece-05 ssary to obtain the long-term shelf stability re-quired for a commercial product.
Useful "meaty materials", which can be reacted according to the present invention before, during or after being held for periods of time in stabilized pumpable meat slurries, are "meat", "meat meal" and "meat by-products". The term "meat" is understood to apply not only to the flesh of cattle, swine, sheep and goats, but also horses, and other mammals, poultry and fish. The term "meat by-product" is intended to refer to those non-rendered parts of the carcass of slaughtered animals including, but not restricted to, mammals, poultry and the like. Both the terms "meat" and "meat by-products" include such ingredients as are embraced by the terms as defined in the official publication of the Association of American Feed Control Officials, Incorporated.
The term "meat meal" refers to the finely ground, dry, rendered residue from animal tissues, including those dried residues embraced by the term "meat meal" as defined by the aforesaid Association.
Because the meat meals are dried under conditions of mois~ heat, they are already of relatively stable bacterial count and do not markedly increase in bacterial count over significant periods of storage.
Thus, meat meal is not a meaty material for which the slurry storage of Franzen et al would be re-quired, and it is not preferable to add it to the slurry prior to the cooking or pasteurization stage because, among other things, it has a tendency to raise the slurry viscosit~ to an undesirable extent.
- t16059 - îO -According to the present invention, however, it can be added to the meaty slurry earlier where desired to standarize the nutritional content in terms of fat, protein, etc., as may be necessary for process 05 control and to take part in the enzymatic reaction, because the enzymatic reaction reduces the slurry viscosity as to make it more flowable and, there-fore, more pumpable.
The meaty material will preferably consti~ute a significant portion of the product; typically, it will be greater than about 10% by weight and pre-ferably greater than 20%. A usual range for such ingredients in intermediate-moisture dog foods is about 20% to 40%, preferably 25% to 35%, by weight.
Non-meat proteinaceous materials, i.e., protein sources other than meaty materials, are preferably employed to achieve a fully-balanced, nutritional feed ration. Typically, the protein will be derived from a vegetable protein source such as soybean, cottonseed, peanuts and the like. The protein may be present in the form of grits, meal, flour, con-centrate, isolate or the like. Additional protein and flavor may be derived from the meat meal and milk products such as dried buttermilk, dried skimmed milk, whey, casein and other like protein sources, such as eggs or cheese.
The process of the invention can be employed to upgrade the palatability of the final dog food by treating at least one of the proteinaceous compon-ents of the food. It is possible, however, to treatall of the proteinaceous components. In practice, a balance will be struck between the degree of improve-ment of the product by treating any individual component, the cost of reacting the component, and the capability of the process to accomodate the reaction mixture in terms of volume, viscosity or the like for the reaction of certain components.
The preservation of moisture-containing, meaty food from microbial decomposi~ion is dependent upon 05 a variety of factors and mechanisms. There are some generally well accepted preservation mechanisms and systems which have evolved in the art, and any preservation system effective for achieving shelf stability in the final product, which is acceptable to dogs, can be employed in the process of the present invention as far as the requirements of the ultimate product preservation system are concerned.
Thus, for example, the prior art products generally employ sugars, salts, polyhydric alcohols and acids as water binders together with anti-microbials such as sorbic acid and its salts.
The usual preservative mechanisms are generally based on a combination of the above principles and exert a combined stabilizing effect. The disclosure of Bur~ et al in U.S. 3,202,514, Bernatovicz in U.S. 3,985,904 and Harrocks et al in U.S. 4,001,445, are of interest in this regard. The reaction slurries preferred according to the present invention, however, do not contain sufficient amounts of preservatives to maintain longer termshelf stability at the moisture contents involved, but will usually be effective for periods of only up to 15 days or so to provide consistently low bac-terial and mold counts to be used in what could be considered good manufacturing practice.
According to preferred embodiment of the pre-sent invention, the desired proteinaceous materials are slurried with the desired preservative materials and an enzyme selected from the group consisting of ficin, trypsin, bromelain, papain, pepsin and com-binations of these, to fo~ the reaction slurry.
The reaction slurry is brought to a temperature of from 30C to 70C and is held there for a period of time effective to release an amount of free amino 05 nitrogen which will indicate that the palatability of the dog food will be su~ficiently increased.
To prepare the slurry, the meaty materials to be used must be comm nuted as by grinding in one or a series of stages. Typically, the meaty materials, usually stored frozen, are first fed to a coarse grinder, such as a Rietz Extructor,* which chops the material into pieces ranging in size up to as long as 2 to 4 inches in major dimension, and starts thawing the meaty materials. The coarsely chopped material is then fed into a secondary grinder, such as a Hobart* grinder, which continues the thawing process and grinds the meaty material, where the majority of the meat pieces have a maximum diameter of from about 1/8 to about 1/2 inch. This type of grinding is conventional and can be successfully employed according to this invention~ However, the best results according to this invention are achieved when the meaty material is yet further ground, i.e., finely ground, to an extent that the majority of the meaty particles are no larger than 0.050 to 0.100 inch in diameter. This fine grinding procedure can be performed in Urschel Comitrol*cr Seydelmann* bowl chopper. To aid the grinding and establish the limited preservation system, the liquid materials in the composition are preferably mixed with the meaty material. Typical of the liquid materials which can be employed are poly-hydric alcohols and corn syrups. Typically, the liquids added will be present at a level of at least 10% of the weight of the meaty material * Trade mark ~D
1 ~ 605~0 After grinding~ the meaty material is ready for reaction and is preferably mixed with any remaining liquid ingredients of the total formulation, i.e., the dog food matrix, as well as other protein mater-05 ials that are desired to be reacted. To accomplishthis, the additional ingredients can be mixed prior to or upon entry into the reaction vessel. Thus, in one embodiment, the meat and preservative solution is mixed and then fed into a reaction tank; and in another embodiment, these ingredients are mixed in the tank.
The pH and temperature of the slurry are both important parameters for the accomplishment of the enz~matic reaction as well as for a number of other reasons. Thus, in addition to its influence on the reaction, the pH of the system is important to the maintenance of microbial stability, and the pump-ability of the slurry. To obtain optimum results in terms of these properties yet maintain a relatively non-corrosive material which does not have to be adjusted in pH radically during final production preparation, the pH will be within the range of from 4.0 to 8.0, preferably from 4.8 to 5.5. If the pH
is substantially above or below the isoelectric point of the protein material in the slurry, the slurry will not be as easily pumpable at the pre-ferred moisture contents.
The temperature has an important effect on the reaction rate and the slurry viscosity. Where the reaction ~emperature drops below about 30C, the reaction rate decreases and the fat in the slurry tends to solidify, coming out of dispersion. This solid fat will interfere with stirring and pumping as well as render the slurry non-homogeneous.
Reaction slurry temperatures will therefore be within the range of from 30C to 70C and will preferably be from 40C to 60C. Most preferably, the temperature is maintained near the upper end of this range for reaction, but is then briefly raised 05 to a temperature effective to inactivate the enzymes, and is then brought back to the lowe~ part of ~he range for continued storage.
The reaction slurry is preferably brou~ht to the effective reaction ~onditions prior to adding the enzymes; however, the enzyme can be added first.
It has been determined, according to the present invention, that the exact amount of enzyme as a percentage of the reaction mixture is not a con-trolling factor. What is important, is that there be sufficient enzymatic acti~7ity at the desired Feaction conditions to effect a sufficient release of ~ree amino nitrogen such that when the reaction mixture is admixed with the remainder of the dog food ingredients, the overall palatability of the composition will be improved as compared to a com-position not treated in this manner. While tests have not indicated an absolute value for free amino nitrogen concentration which will provide this palatability increase, it has been determined that reactions which release sufficient amino nitrogen to at least about one and one half and more preferably about double the starting concentration, will be effective to increase palatability in dog food formulations wherein the treated slurry comprise at least about 10%, and preferably at least about 30%
of the weight of the final dog food formulation.
The free amino nitrogen ~ninhydrin) is determined by the method published in JAOAC:806 (1977). Even more preferably, the reaction will liberate sufficient free amino nitrogen to bring the level of it up to ~ 16~50 about two and one half times that present in the slurry prior to processing.
Testing has shown that it is not necessary to employ any particular concentration or activity of 05 enzyme to obtain a desired result of liberating ~ree amino nitrogen. While any of the enzymes selected from the group consisting of ficin, trypsin, papain, pepsin, and bromelain can be employed according to the present invention with good results, it is presently preferred to employ bromelain. It is difficult to further define the enzyme activity beyond that which the assay reports. The following is a list of enzymes employed and their corres-ponding activity as defined by various suppliers.
Different amounts of the enzymes may be used de-pending on concentration and purity of the enzyme.
This is used to further teach those skilled in the art how to make and use the claimed invention and in no way is meant to limit the scope or definition of the invention.
ENZYMES
PaPain:
One unit will hydrolyze one micro-mole of Alpha-N-Benzoyl-L-Arginine Ethyl Ester (BAEE) per minute at pH 6.2 at 25C.
Man~facturer Activity: 1.6-2.8 BAEE units per mg.
solid Bromelain:
One unit will hydrolyze 1.0 mg. of amino nitro-gen from ~elatin in 20 minutes at pH 4.5 at 45C.
Manufacturer Activity: 2000-4000 units per mg.
protein (BIURET).
~1605~0 Ficin:
One unit will produce a delta-O~280 of 1.0 per minute at pH 7.0 at 37C when measuring trichlor-acetic acid soluble products from casein in a final 05 volume of 10 ml.
Manufacturer Activity: 0.2-0.8 units/mg.
Trypsin:
One BAEE unit = delta-OD253 of 0.001 per minute with Alpha-N-Benzoyl-L-Arginine Ethyl Ester (BAEE) as substrate at pH 7.6 at 25C.
Manufacturer Activity: 1000-1500 BAEE units per mg.
Pepsin:
One unit will produce a delta-A280 of 0.001 per minute of pH 2.0 at 37C, measured as trichloracetic acid soluble products, using hemoglobin as sub-strate.
Manufacturer Activity: 700-1000 units per mg.
protein.
The reaction mixture can be held after process-ing for the period of time necessary for inventory control and then pumped directly to the process for admixture with the remaining pet food ingredients.
Among these ingredients are the dry mateials, such as farinaceous materials, vegetable protein mater-ials, nutrients, further preservatives, and thelike. After mixing, or concurrent therewith, the dog food formulation is then pasteurized.
The preferred reaction slurries do not contain all of the preservation materials employed in the final product. The slurry need be preserved only for the short period of time from receipt into the plant to manufacture into the final pet food material.
~ 16~5~0 This initial period of storage will typically range from about one day up to about five days. To pro-vide a practical degree of safety with cost effect-iveness, however, it is preferred to maintain the 05 meaty materials without refrigeration or freezing for a period of up to at least ten days and pre-ferably a few days longer, say up to fifteen days, to guard against severe inventory problems which may occur despite the best planning.
Intermediate-moisture food preservation systems typically employ preservative materials which are antimicrobial and also materials which control the amount of moisture in a system available as a growth medium. The expression typically employed for defining the amount of water available to support microbial growth is the water activity, AW of a product. The ~ is equal to the vapor pressure of water in the system divided by the vapor pressure of pure water at the same temperature. Theoretically, the ~ of a given system can be lowered to such a degree that the water is not sufficiently available to support any microbial growth. However, to achieve the proper taste and texture for inter-mediate-moisture dog food products, it is not pos-sible as a practical matter to obtain these lowvalues. Where the ~ of the system is not lowered to the absolute point below which organisms will not grow, anti-microbials are also added. Typically, these anti-microbial agents are added to control mold growth which is not sufficiently retarded at the ~ values involved.
~ he water activity of the reaction slurries of the present invention will preferably not be at the low level necessary for long term preservation, and in fact, will preferably be above 0.88 as a function 1 ~ 6~5~0 of the high moisture content necessary to maintain slurry pumpability without the need for large amounts of liquid plasticising additives. Because the major portion of the dry raw materials is not in 05 the slurry, the moisture content and ~ will be higher than would be necessary to have a shelf-stable product.
The final intermediate-moisture products, as distinguished from the reaction slurries, have water binding ingredients dispersed throughout in amounts sufficient to achieve ~ values of below about 0.93;
and further preferably have in contact therewith an anit-microbial agent. The level of the water bind-ing ingredients and anti-microbial agent is suf-ficient to keep the product resistant to microbialgrowth and decomposition when packaged in a substan-tially moisture-impermeable packaging material. The level of anti-microbial agents and ~ lowering ingredients will be balanced to achieve stability at the given moisture content. For example, it may be necessary to employ only a minor amount of anti-microbial agent where the ~ of a given inter-mediate-moisture system is at a level nearly pre-cluding all growth. Conversely, larger amounts of anti-microbial agents may be needed in a moisture containing system wherein the ~ is closer to 0.93.
It is preferred to employ .evels of sorbate salt or sorbic acid anti-microbial~ effective to prevent mycotic or bacterial growth.
Use~ul as water binding ingredients are any of the edible materials which have the ability to tie up water to such an extent that it is no longer usable for microbial growth and propagation. Exem-plary of this group of materials are sugars, polyhy-dric alcohols, mixtures thereof, and mixtures of 1 1 6~5~
alkali metal or alkaline earth salts with sugar and/or one or more polyhydric alcohols.
The polyhydric alcohols useful as liquid pre-servatives for use in the slurries are pre~erably 05 polyhydric alochols having from 3 to 7 carbon atoms.
Preferred dihydric alcohols are 1,2-propanediol and 1,3-butanediol. Glycerine, a trihydric alcohol, is a very effective water binder and may be alone or in combination with a dihydric alcohol. Other useful polyhydric alcohols include tetritols, such as erythritol or the threitols; pentitols, such as ribitol or xylitol; hexitols such as sorbitol or manitol; and heptitols, such as perseitol or volem-itol.
Sugars usef~l as water binding agents include the reducing and non-reducing water soluble mono-and polysaccharides; e.g., pentoses such as xylose and arbinose; hexoses such as glucose, fructose or galactose; and disacharides such as lactose, sucrose and maltose. To be effective as a bacteriostatic agent, the sugars are preferably water soluble and of such a low molecular weight as to be effective in increasing the osmotic pressure of the aqueous system in which it is dissolved. Preferred sugars are sucrose, dextrose and highly converted corn syrups, especially high fructose corn syrups.
Various alkali metal and alkaline earth metal halide salts are also effective water binding agents Preferred salts are sodium chloride and calcium chloride.
The provision of an acid medium by the addition of acid or acid salts will also aid in preventing microbial decomposition. Preferred acids include phosphoric, citric, malic, fumaric, hydrochloric, sulfuric, lactic, acetic, adipic and the other known 1 ~ 6~5~0 non-toxic acids. Phosphoric acid is the most pre-ferred due to its use as a source of phosphorous.
Similarly, the provision of an alkaline environment can aid in preparation. Preferred alkaline ma~er-05 ials are calcium hydroxide and sodium hydroxide.
The preferred solutions for adding to thereaction slurries of meaty materials according to the present invention will contain a polyhydric alcohol, such as propylene glycol, and an anti-microbial such as potassium sorbate. The reactionslurry will thus have sufficient flowability for processing as well as have suitable stability for holding in the reaction tank for extended periods after reaction. The most preferred systems will also contain other water binders in the form of salts and sugars and contain acid or alkaline materials to modify the pH from near neutral to a value less conducive to microbiological growth. It is preferred to adjust the pH of the final product to a level between 5 and 8, where dogs find the product palatable. This can be done by overt addi-tion of a neutral:izing medium or by the natural buffering capacity of the dry ingredients.
A particularly preferred system contains pro-pylene glycol, potassium sorbate, sodium chlorideand phosphoric acid to adjust the slurry pH to a value of from 4.0 to 8Ø The optimum results have thus far been achie~ed using pH values of about 5.5.
At pH values about this level, both the enzymatic reaction during the reaction period and preservation of both the slurry and the final product are aided.
Moreover, the slurry viscosity during storage is suitably low due to maintenance of the pH near the system isoelectric point. Mixing the additional dog food ingredients will adjust the pH of the final ~ 5~0 product to within the preferred range.
After admixing all the remaining dog food ingredients, the complete formulation is preferably pasteurized. The pasteurization can be performed 05 either continuously or batchwise, and heating can be either direct by injection of steam or indirect by employing a heated jacket on the cooker. Continuous operation with direct steam injection in an extruder-cooker is preferred. Typical of the continuous cooking devices which can be employed are an ~nder-son extruder-cooker and a Wenger mixer-conditioner.
For batchwise pasteurization, a simple kettle fitted with a stirring device adequate to keep the matrix material under constant agitation, can be employed. Heat can be supplied by steam supplied to a jacket around the kettle.
Upon discharge from the cooker, the dog food matrix is preferably cooked prior to shaping into the desired final product form. It is possible with the continuous pasteurization to employ a cooling jacket around the final stage of the extruder-cooker to enable shaping to the desired final size directly upon exiting the extruder. Typically, however, the matrix material is discharged into a separate cool-ing device which may be of any conventional con-struction, for example, a wire mesh belt, a per-forated deck, or a jet zone cooler~ wherein cooled air at temperature of about 20C is directed across the matrix material. To enable optimum shaping and handling characteristics, the matrix material is preferably cooled to a temperature of below 30C, and preferably to about 25C. The final shaping and packaging of the product from this point on can be done in conventional manner, for example, usin~ the teachings of the Burgess et al patent, U.S.
3,20~,514, mentioned above.
Best Mode For Carry~ Out The Invention The following Examples are for the purpose of further illustrating the present invention and are not to be taken as limiting in any regard. Unless 05 otherwise indicated, all parts and percentages are by weight.
Example I
According to this example, the preparation of an intermediate-moisture dog food according to the invention described wherein a portion of the meaty materials were reacted with bromelain to improve the palatability of the food.
In preparing the food, the following ingre-dients were finely chopped and slurried in accor-dance with the procedures set forth in U . S . Patent 4,212,894, granted July 15, 1980, to Franzen et al and assigned to the assignee of the present invention:
In~redient Parts 20 Beef Tripe and Trimmings 36.5 Soy Grits 32.6 Sucrose 17.4 Propylene Clycol 5.2 Corn Syrup 3.0 Phosphoric Acid (85%) 0.26 Soy Protein Isolate 1.9 Dried Whey 1.0 Iodized Salt 1.25 Monocalcium Phosphate 0.96 30 Calcium Carbonate 1.0 Soybean Hulls 2.2 Sodium Carboxymethylcellulose 0.5 Mono- and Di-Glyceride Emulsifier 0.5 Flavor, Color, Vitamins and Minerals .8 35 Potassium Sorbate 0.17 1 t 6~50 Of these, the meaty materials (beef tripe and trimmings), propylene glycol, potassium sorbate, sodium chloride and phosphoric acid were mixed to form a slurry. The meaty materials were first 05 ground frozen through a 0.95 cm hole die on a Hobart grinder. The ground meats were then placed in a Baker-Perkins Sigma*bladed mixer and the other noted materials were added to form a meaty slurry. The slurry was then divided into two portions for use in preparing two dog food formulations, identified as test (Tl) and control (Cl). Portion Tl was treated by heating it to 60C, admixing therewith 0.1% Miles Bromelain llOO*based upon the weight of the slurry, (available from Miles Laboratories), maintaining the temperature at that level for 1 hour, and then sharply raising the temperature to about 75C to inactivate the enzyme. The Miles Bromelain 1100 had a proteolytic activity of 1100 bromelain tyrosine units (BTU's) as measured by the quantity of enzyme needed to produce one micromole of tryosine per minute under conditions of the assay. The free amino nitrogen of portion Tl was about twice that of portion Cl.
The dry ingredients were separately blended and then mixed in a Day Cooker*equipped with a sigma arm mixer. Portions Tl and Cl were then heated at about 82C for about 15 minutes to provide the necessary heating for pasteurization. Upon exiting the cooker, the pasteurized products Tl and Cl were cooled by air at about 20C to a temperature of 25C. The cooled formulations were then shaped in a Bonno~ extruder fitted with a die plate having 0.4 cm diameter holes. The formed products were then heat sealed in polypropylene film bags.
The separate samples prepared in this manner, * Trade Mark ~ .
dog foods T1 and sample Cl, were fed to a panel of 120 dogs for 1 day. The do~ food T1 was signi-ficantly preferred to C1.
Example II
05 The procedure for the control of Example I was repeated to prepare a control sample C2, but this time a test sample, T2, was prepared using a mixture of soy grits, water and tallow to replace the meat portion of the control, C2, formula. According to the invention, a mixture of 36.2 parts soy grits and 42.9 parts of water was enzymatically treated with 0.08 parts of papain for 15 minutes at 40C at the end of the treatment, 20.8 parts of tallow were added to the mixture and the remaining formula ingredients added and processed u3ing the procedure of Example I. A second control, Cs was prepared in the same manor as T2 but without the enzymatic treatment of the soy. For example T2 and Cs the soy, water, tallow mixture was formulated to contain the same protein, fat and moisture levels as the meat slurry. Here T2 was significantly preferred to both C2 and Cs. The enzyme used was Type I crude papain obtained from the Sigma Chemical Co.
Example III
This example illustrates the preparation and testing of a dry dog food improved according to the present invention. A control sample (C3) and a test sample (T3~ were prepared from the following ingredients:
Ingredient Parts Whole Ground Corn 37.8 Hominy Feed 3.6 Wheat Middlings 18.2 1~6~500 - ~5 -Soybean Oil Meal 23.1 Meat Meal 14.8 Vitamins, Minerals, Salt, Color, Etc. 2.5 05 The ingredients were processed in the same manner as Example I to produce samples C3 and T3, except that in preparing sample T3, the soybean oil meal and meat meal portions of the formula were treated with a protease enzyme by admixing Miles Bromelain 1100*
to a level of 0.1% based on the weight of the pro-teinaceous material of a 1:1 slurry of the protein-aceous ingredients and water and heating to 60C for four hours. The treated slurry was then mixed with the remaining ingredients, run through an Anderson *
cooker/ expander, and dried to about 9% moisture.
For the C3 sample, the ingredients were mixed and processed through the Anderson cooker/extruder at the same moisture/ temperature conditions and dried to about 9% moisture. The two samples were fed to dogs for two days using standard paired com-parison testing procedures. The T3 sample was ~igniicantly preferred to the C3 sample by the dogs.
This example illustrates the preparation of an intermediate-moisture dog food according to the present invention. A test sample T4 was prepared from the following ingredients.
Ingredient Parts Wheat Flour 21.2 Soybean Oil Meal 15.6 Meat Meal 15.0 Whole Ground Corn 14.5 Isomerose~Corn syrup blend 7.0 * Trade mark C
t t 6~00 Tallow 4,0 Propylene Glycol 4.0 Salt 1.0 Soy Oil 1.0 05 Potassium Sorbate 0.15 Vitamins/Minerals/color .13 Miles Bromelain 1100 0.005 Water 16.5 A slurry was prepared by mixing 2/3 of the meat with water at a 1:1 ratio. The slurry was heated to 60C. The Miles Bromolain 1100 was added and the slurry held at 60C for 30 minutes under constant agitation. At the end of the hold time, the temper-ature of the slurry was raised to 82C and held for minutes to inactivate the enzyme. The liquid ingredients, mainly, the soy oil, propylene glycol, and the Isomerose/corn syrup blend, were added to the meat meal slurry. The remaining dry ingredients were separately blended and then admixed with the slurry. The resulting mixture was processed through an Anderson cooker/expander with the water added into the cooker/expander. The resulting expanded product was cooled on a wire mesh screen using ambient air, and surface coated with tallow.
The test sample was fed to 60 dogs for 2 days versus a commercial intermediate-moisture product (C4) using a standard paired comparision testing procedure. No difference was seen between the ~wo samples. A second con~rol sample (Cs) prepared using the same formula and process but without the enzyme treatment was significantly less preferred when fed versus the commercial intermediate-moisture product C4.
11~$500 Example V
Samples T5 and T6 were prepared in accordance with the procedure outlined in Example 1 in which a meat slurry was treated with ~he enzyme trypsin for 05 1 hour at 40C. The levels of trypsin used were O.01% and 0.1% based on the meat slurry. When fed versus an untreated control, both trypsin treated samples T5 and T6 were significantly preferred by the dogs.
Example VI
A sample was prepared according to the pro-cedure outlined in Example l in which a meat slurry was treated with the enzyme ficin for one hollr at 40C. The level of enzyme used was 0.1% based on the meat slurry. When fed against an untreated control the test sample was significantly preferred by dogs.
Example VII
A test sample was prepared in accordance with the procedures outlined in Example 1 in which a meat slurry was treated with the enzyme pepsin for one hour at 40C. The level of enzyme used was 0.1%
based on the meat slurry. When fed against an untreated control the test sample was significantly ~5 preferred by the dogs.
Example VIII
According to this Example, the preparation of a dry dog food is accomplished according to the invention wherein a portion ~f the proteinacious material is reacted with papain to improve the palatability of the pet food.
In preparing the food, T~, the following ingre-dients w~re processed in the same manner as Example III. The meat meal portion of the formula was treated with papain to a level of 0.5% based on the 05 weight of the proteinaceous material of a 2:5 slurry of the proteinaceous ingredient and water and heat-ing to 55C for three hours. The treated slurry was then mixed with the remaining ingredients, run through an Anderson cooker/expander and dried to about 9% moisture. Control sample, C8, used the same ingredients except instead of enzyme treated meat meal, poultry meal was substituted. The ingre-dients were mixed and processed through the Anderson cooker/extruder at the same moisture/ temperature condi~ions and dried to about 9% moisture. The two samples were fed to dogs using standard paired test-ing procedures. The T8 sample and the control C8 sample were equal in preference levels. Thus one skilled in the art will recognize that papain treat-ment of meat meal upgrades it to the preferencelevel of poultry meal.
Ingredient Parts Whole Ground Corn 37.8 Hominy Feed 3.6 Wheat Middlings 18.2 Soybean Oil Meal 23.1 Meat Meal 14.8 Vitamins, Ninerals, Salt, Color, Etc. 2.5 The above description is for the purpose of teaching those skilled in the art how to practice ~he present invention and is not intended to recite all the possible modifica~ions and variations there-116~00 of which will become apparent to the skilled worker upon reading. It is intended, however, that all such modifications and variations be included within the scope of the invention which is defined by the 05 following claims.
Claims (23)
1. In a process for preparing a nutritionally balanced dog food comprising protein, fat, carbohy-drates, vitamins and minerals wherein at least one proteinaceous component is cooked and shaped into a dog food product, the improvement which comprises:
heating at least a portion of at least one proteinaceous component to a temperature within the range of from 30°C to 70°C and reacting it with an enzyme selected from the group consisting of ficin, trypsin, bromelain, pepsin, and papain, under con-ditions effective to release free amino nitrogen, and;
admixing the resulting reaction mixture with the other components of the dog food in an amount effective to provide a significant increase in palatability of the dog food to dogs.
heating at least a portion of at least one proteinaceous component to a temperature within the range of from 30°C to 70°C and reacting it with an enzyme selected from the group consisting of ficin, trypsin, bromelain, pepsin, and papain, under con-ditions effective to release free amino nitrogen, and;
admixing the resulting reaction mixture with the other components of the dog food in an amount effective to provide a significant increase in palatability of the dog food to dogs.
2. A process according to claim 1 wherein the reaction of the proteinaceous component with the enzyme releases sufficient free amino nitrogen to increase the total amount of free amino nitrogen present in the proteinaceous component to at least one and one half times the amount present prior to processing.
3. A process according to claim 2 wherein sufficient free amino nitrogen is released to in-crease the total amount of it in the proteinaceous component to at least two times the amount present prior to processing.
4. A process according to claim 3 wherein sufficient free amino nitrogen is released to in crease the total amount of it in the proteinaceous component to at least two and one half times the amount present prior to processing.
5. A process according to claim 2 wherein the nutritionally balanced dog food has a moisture content of less than 15% by weight.
6. A process according to claim 1 wherein the nutritionally balanced dog food has a moisture content between about 15% and 50% by weight.
7. A process according to claim 1 wherein the nutritionally balanced dog food has a moisture content in excess of 50% by weight.
8. A process according to claim 1 wherein the proteinaceous component of the dog food which is treated with the enzyme is selected from the group consisting of meat, meat by-products, soy grits, soy bean oil meal and combinations of these.
9. A process according to claim 1 wherein the dog food is shaped by extrusion.
10. A process according to either of claims 1 or 9 wherein the dog food expands to incorporate from about 25% to about 75% by volume of void spaces.
11. A process according to claim 10 wherein the expanded dog food is dried to a moisture content of less than 15% by weight.
12. A process according to claim 1 wherein the enzyme comprises bromelain.
13. A process according to claim 1 wherein the enzyme comprises papain.
14. A process according to claim 1 wherein the proteinaceous material treated with the enzyme comprises meat.
15. A process according to claim 1 wherein the proteinaceous material treated with the enzyme comprises soy products.
16. A process according to claim 1 wherein the proteinaceous material treated with the enzyme comprises meat by products.
17. A process according to claim 1 wherein, prior to reacting with the enzyme, the proteinaceous materials treated with the enzyme are slurried with sufficient preservatives to maintain the protein-aceous material free from microbial spoilage for a period of at least five days.
18. A process according to claim 17 wherein the proteinaceous material in the slurry comprises meat or meat by-products.
19. A process according to claim 18 wherein the enzyme comprises papain.
20. A process according to claim 18 wherein the enzyme comprises bromelain.
21. A process according to claim 18 wherein the dog food is shaped by expressing it from an extruder under pressure.
22. A process according to either of claims 1 or 17 wherein the proteinaceous material is reacted with the enzyme prior to pasteurizing.
23. A product prepared according to the pro-cess of claim 1.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US9122579A | 1979-11-15 | 1979-11-15 | |
| US091,225 | 1979-11-15 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1160500A true CA1160500A (en) | 1984-01-17 |
Family
ID=22226686
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000362795A Expired CA1160500A (en) | 1979-11-15 | 1980-10-20 | Process for preparing a dog food of improved acceptability |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5685255A (en) |
| CA (1) | CA1160500A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013050407A1 (en) * | 2011-10-03 | 2013-04-11 | Specialites Pet Food | Meat tissue digests having enhanced palatability for use in pet food |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60184360A (en) * | 1984-03-01 | 1985-09-19 | Ajinomoto General Food Kk | Method for improving palatability of pet food |
| JP2011524165A (en) * | 2008-06-03 | 2011-09-01 | ネステク ソシエテ アノニム | Taste improving agent and method for improving taste |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5191178A (en) * | 1974-12-30 | 1976-08-10 |
-
1980
- 1980-10-20 CA CA000362795A patent/CA1160500A/en not_active Expired
- 1980-11-15 JP JP16131880A patent/JPS5685255A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2013050407A1 (en) * | 2011-10-03 | 2013-04-11 | Specialites Pet Food | Meat tissue digests having enhanced palatability for use in pet food |
| AU2012320644B2 (en) * | 2011-10-03 | 2016-09-08 | Specialites Pet Food | Meat tissue digests having enhanced palatability for use in pet food |
| RU2611154C2 (en) * | 2011-10-03 | 2017-02-21 | Спесиалите Пет Фуд | Overcooks of meat tissues with improved taste attractiveness for application in fodders for animals |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5685255A (en) | 1981-07-11 |
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