CA2158752A1 - Animal food palatability improving composition and process - Google Patents

Abstract

The present invention relates to a process for preparing a composition for improving the palatability of animal food, said process comprising: (a) preparing an initial mixture comprising a proteinaceous material and a proteinhydrolyzing enzyme, wherein said protein-hydrolyzing enzyme comprises from 0.01 % to 0.5 % by weight of said initial mixture; (b) hydrolyzing the protein contained in the proteinaceous material of the initial mixture, thereby forming a hydrolyzed mixture, wherein said hydrolysis is carried out under conditions sufficient to hydrolyze a sufficient amount of protein to improve the palatability of an animal food when the composition resulting from step (f) of this process is combined with said animal food; (c) inactivating the protein-hydrolyzing enzyme contained in the hydrolyzed mixture, thereby forming an inactivated mixture; (d) heating or maintaining the inactivated mixture in an initial heating stage at a temperature in the range of from 80 ·C to 100 ·C for a period of time in the range of from 10 to 300 minutes; (e) following the initial heating stage, adjusting the pH of the inactivated mixture to within the range of from 2.8 to 3.8 while maintaining the temperature of the inactivated mixture in the range of from 80 ·C to 100 ·C, thereby forming an acidic mixture; and (f) heating or maintaining the acidic mixture in a final heating stage at a temperature and for a period of time sufficient to provide a composition which improves the palatability of animal food when combined therewith, thereby producing a palatability improving composition. The present invention still further relates to an animal food product having improved palatability, said product comprising animal food and an amount of said palatability improving composition sufficient to improve the palatability of said animal food. The present invention still further relates to a method of improving the palatability of animal food, said method comprising combining animal food with amounts of said palatability improving composition to improve the palatability of said animal food.

Description

wo 95/215~0 2 1~ 8 ~ 5 ,~ PCT/US95/01510 ANIMAL FOOD PALATABILITY IMPROVING COMPOSITION AND PROCESS

FTFT n OF INVENTION

The present invention relates to a composition which, when applied to animal food, 10 improves the flavor and the aroma, or palatability, of the animal food. The present invention also relates to the process for ~ p~;llg said composition. The present invention further relates to an animal food product having an improved flavor and aroma, or palatability, due to its combination with said palatability improving composition.
BACKGROUND OF INVENTION
There is a co~.l;.. ;.~g effort to develop processing and formulations which improve the palatability of animal food while mAi~lA;~ g its nutritional value. The improvement of palatability in animal food is important from at least two standpoints. First, it assures that the animal will consume a sufficient quantity of the food to mAintAin a healthy existence.
Second, it enables the use of large amounts of basic food ingredients and by-products from the human food industry. This helps reduce the cost of human food production by providing a market for the by-products of this industry, while at the same time minimi7.ing the dçnnAn~
of the animal feed industry for the choicer and more select raw materials which are suitable for human conswl~lion. The present invention provides for such animal food having improved palatability.
BACKGROUND ART
There are numerous processes known in the art for improving and enhancing the palatability of animal food.
U.S. Patent 3,857,968, issued December 31, 1974, to Haas et al., discloses a process for improving the palatability of an animal food. The disclosed process comprises conditioning an aqueous meat slurry, comprising fat and protein, by emulsifying the fat in the meat slurry with the water present in the slurry, and treating the meat slurry, contAining the emulsified fat and the protein, with an en_yme mixture comprises lipase and protease in 2ls~52 2 amounts effective to cause an enzymatic reaction resulting in the production of a palatability improving composition. Haas et al. also disclose incorporating this palatability improving composition into an animal food in an amount which is effective to increase the palatability of the animal food.
U.S. Patent 3,968,255, issued July 6, 1976, to Haas et al, discloses a process for improving the palatability of an animal food. The disclosed process comprises conditioning an aqueous meat slurry, comprising fat and protein, by emulsifying the fat in the meat slurry with the water present in the slurry, and treating the meat slurry, co~ E the emulsified fat and the protein, with lipase and protease in amounts, under conditions of pH and temperature, 10 and for a time, effective to cause an enzymatic reaction resulting in the production of a palatability improving composition. Haas et al. also disclose incorporating this palatability improving composition into an animal food in an amount which is effective to increase the palatability of the animal food.
U.S. Patent 4,089,978, issued May 16, 1978, to Lugay et al., discloses a method for 15 increasing the palatability of a nutritionally balanced dry dog food. The disclosed method comprises: (a) reacting an aqueous lllixlule of a reducing sugar, animal blood, fat, yeast or yeast extract with lipase and protease, at a telllpcldlulc, pH, and for a time effective to cause lipolytic and proteolytic reaction, (b) heating the resulting aqueous reaction lnixlulc to a telllpcldlulc and for a time effective to inactivate the enzymes and to also further develop the 20 palatability of the mixture, to produce a palatability enhancer and (c) applying an external coating of the palatability enhancer onto a dog food in an amount, between 1 % and 5% based on the total weight of the dog food, which is effective to increase the palatability of the dog food.
U.S. Patent, 4,294,857, issued October 13, 1981, to Fuller, discloses a dog food25 composition having greater palatability to dogs than the same composition without the palatability enhancer. The dog food composition comprises a nutritionally balanced mixture of proteinaceous and farinaceous ingredients, and an added palatability enhancing 0.0001 to 0.01% by weight amount of linalool.

215~7~
WO 95/215'10 PCT/US95/01510 U.S. Patent 4,296,132, issued October 20, 1981, to Lazarus et al., discloses an improved nutritionally balanced dog food comprising fat, protein, carbohydrates, vitamins and minerals wherein the improvement consists of magnesiulll oleate in adlllixlu~ with at least a portion of the fat, the m~gn~Sium oleate being present in an amount effective to S improve the palatability of the dog food for dogs.
U.S. Patent 4,391,829, issued July 5, 1983, to Spradlin et al., discloses a process for pl~;ng a nutritionally balanced dog food having improved palatability. The dog food comprises fat, protein, carbohydrates, vitamins and minerals and contains on a weight basis from 20% to 80% farinaceous material and from 20% to 80% proteinaceous ingredients, 10 including ploteillaceous meaty material at from 25% to 55% by weight of the proteinaceous ingredients. The disclosed process comprises the steps of (a) pl~ u;llg a farinaceous slurry comprising from 30% to 70% water and from 5% to 25% of the total weight of said farinaceous ingredients; (b) forming a farinaceous reaction product by treating the farinaceous m~teri~l in said farinaceous slurry with added alpha-amylase and protease enzymes in an 15 amount and under conditions effective to convert at least a portion of the f~rin~ceous material to a mixture of oligo saccharides ranging in size from 1 to 10 monomer units, and at lest a portion of the proteinaceous material to a IlliXLUlc; of peptides ranging in size from 2 to 300 monomer units, and effective to reduce the viscosity of the slurry by 50%; (c) plep~illg a proteillaceous slurry comprising water and a major portion of the proteinaceous meaty 20 m~teri~l; (d) forming a proteinaceous reaction product by treating the proteinaceous material in the proteinaceous slurry with protease enzyme in an amount and under conditions effective to convert at least a portion of the proteinaceous material to peptides ranging in size from 2 to 300 monomer units and effective to reduce the viscosity of the slurry by 50%; and (e) incorporating the farinaceous and proteinaceous reaction products into a dog food in an 25 amount effective to provide a significant increase in the palatability of the dog food.
U.S. Patent 4,393,085, issued July 12, 1983, to Spradlin et al., discloses a process for prep~illg a nukitionally-balanced dog food having improved palatability. The dog food comprises fat, protein, carbohydrates, vitamins and minerals and contains on a weight basis WO 95/21540 r ~ PCT/US95/01510 2~5~ a ~

from 20% to 80% farinaceous ingredients and from 20% to 80% proteinaceous ingredients, including proteinaceous meaty material at from 25% to 55% by weight of the proteinaceous ingredients, said process comprising the steps of: (a) yrep~;llg a slurry comprising water, from 5% to 25% of the total weight of said farinaceous ingredients, and a major portion of the 5 proteinaceous meaty m~tcen~l; (b) forming a reaction product by treating said slurry with added alpha-amylase and added protease enzymes in an amount and under conditionseffective to convert at least a portion of the f~rin~reous material to a mixture of oligo saccharides ranging in size from 1 to 10 monomer units, and at least a portion of the proteinaceous material to a ~ Lul~ of peptides ranging in size from 2 to 300 monomer units, 10 and effective to reduce the viscosity of the slurry by 50%; and thereafter, (c) incorporating the reaction product of the slurry into a dog food in an amount effective to provide a significant increase in the palatability of the dog food to dogs.
U.S. Patent 4,713,250, issued December 15, 1987, to Tonyes et al., discloses a process for preydl;llg a dog food palatability enhancer. The disclosed process comprises: (a) 15 p,epal;ng a first stage reaction product by dispersing a substrate comprising a proteinaceous or farinaceous material in water and reacting the substrate with an enzyme or enzyme mixture comprising amylase when the substrate comprises f~rinAr,eous m~t~ l and protease when the substrate comprises proteinaceous material, in amounts, under conditions of pH and tellly~d~ule~ and for a time effective to partially hydrolyze the substrate; (b) yl~y~;ng an 20 emulsion comprising fat and said first stage reaction product; and then (c) reacting said emulsion with lipase and protease in amounts, under conditions of pH and temy~ldL~lre~ and for a time, effective to cause an enzyme reaction resulting in the production of a palatability enhancer.
U.S. Patent 4,804,549, issued February 14, 1989 to Howley et al., discloses a method 25 of enhancing the palatability of an nutritionally balanced dog food with high levels of fats including high free fatty acids and which is resistant to package staining. The disclosed method compromises blending a high free fatty acids, and encapsulating binder comprising a protein or a carbohydrate, and water to from an emulsion. The emulsion is dried to produce a 21 ~7 ~

palatability enhancer in flowable, particulate form. Pieces of dog food having exterior surfaces are then provided, and the palatability enhancer, which is in flowable particulate form, is mixed with the pieces of dog food.
U.S. Patent 5,186,964, issued February 16, 1993, to Gierhart et al., discloses a method of increasing the palatability of an extruded dry cat food composition. The disclosed process comprises topically applying to the cat food a palatability-improving composition consisting essentially of from 0.1 to 99%, by weight, of sodium acid pyrophosphate, in sufficient quantity to deposit from 0.5 to 2.0% of said sodium acid pyrophosphate, by weight of the food composition.
While there is extensive te~r~ling in the art of methods to improve the palatability of animal food, there is nothing in the art which teaches the animal food palatability improving composition of the present invention, nor the process for its p~ lion.
It is therefore an object of the present invention to provide a process for preparing a composition which improves the palatability of animal food.
It is another object of the present invention to provide a process for producing said animal food palatability improving composition. It is still a further object of the present invention to provide an animal food having improved flavor and aroma, or palatability.
These objects are accomplished by the invention described herein. Unless otherwise specified, the percentages provided herein are weight pelcell~ges.
SUMM~RY OF THE INVENTION
The present invention relates to a process for prepa~ g a composition for improving the palatability of animal food, said process comprising:
(a) plep~uing an initial llliX~Ule comprising a proteinaceous material and a protein-hydrolyzing enzyme, wherein said protein-hydrolyzing enzvme comprises from 0.01% to 0.5% by weight of said initial mixture;
(b) hydrolyzing the protein contained in the proteinaceous material of the initial mixture, thereby forming a hydrolyzed mixture, wherein said hydrolysis is carried out under conditions sufficient to hydrolyze a sufficient amount of WO 95/21540 ," PCTIUS95/01510 ~lS~ 6 protein to improve the palatability of an animal food when the composition resulting from step (f) of this process is combined with said animal food;
(c) inactivating the protein-hydrolyzing enzyme contained in the hydrolyzed Illixlule, thereby forming an inactivated-mi~ e, (d) heating or m~ t~ ing the inactivated mixture in an initial heating stage at a temperature in the range of from 80C to 100C for a period of time in the range of from 10 to 300 minlltçs;
(e) following the initial heating stage, adjusting the pH of the inactivated mixture to within the range of from 2.8 to 3.8 while m~ -il-g the temperature of the inactivated mixture in the range of from 80C to 100C, thereby forming an acidic llli~ e; and (f) heating or Ill~ g the acidic Illi~ in a final heating stage at a telllpc;ldlule and for a period of time sufficient to provide a composition which improves the palatability of animal food when combined therewith, thereby producing a palatability improving composition.
The present invention further relates to the palatability improving composition produced by said process.
The present invention still further relates to an animal food product having improved palatability, said product comprising animal food and an amount of said palatability improving composition sufficient to improve the palatability of said animal food.
The present invention still further relates to a method of improving the palatability of animal food, said method comprising combining animal food with amounts of said palatability improving composition to improve the palatability of said animal food.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a process for p~ep~;llg a composition which improves the palatability of animal foods, and preferably improves the palatability of pet foods such as dog food. The present invention also provides a palatability improving composition prepared by the process of the present invention.

WO 95/21540 21~ ~ 7 ~ ~ PCT/US9S101510 In the process of the present invention an initial mixture comprising a proteinaceous material and a protein-hydrolyzing enzyme is prepared. The proteinaceous material is one that provides a positive palatability response when hydrolyæd, and is preferably capable of being emulsified and is available in quantity at a reasonable cost. Any proteinaceous material 5 known to those skilled in the art as providing such a positive palatability response may be used in the present innovation. Examples of such proteinaceous materials useful in the present invention include, but are not limited to, meat, soy products, whey, chicken skins, cheese, gluten, meat-by-products, animal offal, poultry-by-products, brewer's yeast, and llliX~ S thereof, with meat being pl~Çclled.
Any meat source known to those skilled in the art may be used in the present invention. Examples of meat sources useful herein include, but are not limited to, beef liver, deboned beef meat, pork liver, chicken livers and parts, chicken viscera, beef, pork, chicken, turkey, fish, and mixtures thereof.
Especially plefcll~d are proteinaceous materials which additionally provide all or part of the protein-hydrolyzing enzyme also contained in the initial mixture, such as chicken viscera. Preferred is a combination of from 30% to 70%, more preferably from 40% to 60%
by weight chicken viscera, and from 30% to 70%, more preferably from 40% to 60% by weight beef livers, wherein said weight l.eleelllages are based on the weight of the initial llliX~ c.
The initial mixture of the present invention also comprises a protein-hydrolyzing enzyme. This protein-hydrolyzing enzyme may be provided to the initial mixture either by the addition of a purified sample of a protein-hydrolyzing enzyme, or, as already stated herein, may be included as an indigenous component of the proteinaceous material added to the initial mixture. One skilled in the art will appreciate that the proteinaceous material and protein-hydrolyzing enzyme are combined in a manner to allow for sufficient hydrolysis of the proteinaceous material.
Any protein-hydrolyzing enzyme known to those skilled in the art may be used in the present invention. Examples of useful protein-hydrolyzing enzymes include, but are not ~15~5~ 8 limited to, protease enzymes. It is ~;ullclllly contemplated that any protease enzyme derived from plants, ~nim~l~, or microorg~ni~m~, can be employed in the present invention, as long as it is capable of providing the requisite improvement in palatability. Examples of protease enzymes useful herein include, but are not limited to, plant proteases such as bromolein and 5 papain, proteases derived from B.cuptilis, and animal derived enzymes such as trypsin and pepsin. A pl~r~lled protease is Alkalase 0.6 L enzyme, which is m~nllf~ctllred by the Enzyme Process Division of Bioin-11lctri~1 Group, Novo Nordisk A/S, located in Denm~rk As far as is known, Novo Nordisk has a sales office located in Danbury, CT. According to Novo Nordisk's sales literature, Alkalase 0.6 L is produced from a selected strain of Bacillus 0 licheniformis. The main enzyme component, Subtilisin A ( = Subtilisin Carlsberg), is an endoproteinase, which is extensively described in the literature.
While the degree of enzymatic action of the protein-hydrolyzing enzyme is dependent upon a number of factors, the protein-hydrolyzing enzymes will typically be employed in an amount and for a period of time effective to provide generation of desired polypeptides to 15 achieve palatability improving properties in the final product of the process of the present invention. The protein-hydrolyzing enzyme typically comprises from 0% to 1%, preferably from 0.01% to 0.75%, more preferably from 0.1% to 0.5% by weight ofthe initial mixture.
The various protein-hydrolyzing ~l~ylllcs come in a wide variety of commercial forms, including dry, purified enzymes; enzymes supported on various soluble and insoluble 20 carriers; and enzyme solutions of various strengths.
The initial mixture is typically pl~ ,d by combining the proteinaceous material with the protein-hydrolyzing enzyme, and this could be done by any manner known to those skilled in the art. For ease of h~n-lling, especially in view of the effect of those materials in body tissues, it is preferred to add the protein-hydrolyzing enzyme to the initial mixture in the 25 form of a liquid solution. In addition, water may be added to the initial mixture to allow improved mixing of the proteinaceous material and enzyme.
After the initial mixture is prepared, it is reacted to prepare a hydrolyzed mixture. The initial mixture is reacted under conditions sufficient to hydrolyze a sufficient amount of 'VO 95/21540 PCT/US95/OlS10 21~752 protein available in the initial mixture to impart palatability-improving properties to the composition product of the process of the present invention. Preferably at least 85%, more preferably at least 90%, still more preferably at least 95% by weight of the protein available in the initial lllixlulc is hydrolyzed.
The protein hydrolysis is typically carried out at a tenlylldlule in the range of from 40C to 75C, preferably from 45C to 75C, still more preferably from 55C to 65C, for a period of time in the range of from 5 to 240, preferably from l 5 to 120, still more preferably from 30 to 120 minutes. When adding heat to carry out the protein hydrolysis, care should be taken to avoid inactivating the protein-hydrolyzing enzyme. Also, as will be appreciated by 10 one skilled in the art, if stearn is used to supply heat for the hydrolysis reaction, the steam may condense, which in turn may contribute water to the initial mixture.
After the protein present in the initial mixture is sufficiently hydrolyzed, a hydrolyzed lllixlulc is formed. The protein-hydrolyzing enzyme contained in the hydrolyzed nlixlulc is then substantially inactivated, thereby forming an inactivated mixture. The protein-15 hydrolyzing enzyme is preferably inactivated by heating the hydrolyzed mixture to a tt;lllyeldlulc sufficient to inactivate the particular protein-hydrolyzing enzyme. For the yrcr~lled protein-hydrolyzing enzyme ~lk~l~ce 0.6 L, this is accomplished by heating the hydrolyzed llli~lule to a temytldlulc of at least 80C, preferably at least 85C, still more preferably at least 90C.
Other methods of inactivating the protein-hydrolyzing enzyme may be used, although care must be taken to avoid inactivating any protein-hydrolyzing enæymes through adjustment of the pH. The point in which the pH is adjusted in the present invention is critical, and any early adjustment of the pH will have an adverse effect on the product of a process of the present invention, i.e., will reduce its palatability improving effectiveness.
The inactivated mixture is then heated in an initial heating stage. In this initial heating stage the inactivated lllixlulc is heated to a temperature in the range of from 80C to 100C, preferably from 85C to 95C, more preferably from 87C to 92C, for a period of time in a range of from 10 to 300 minl.tec, preferably from 15 to 120 minutes, still more ?,~S~5~ lo preferably from 30 to 60 minutes. This initial heating stage may also involve m~int~ining the te~ ld~ule of the initial mixture at an already elevated level, for example by insulating the reaction vessel.
Following the initial heating stage, the pH of the inactivated llliX~Ule iS adjusted to within the range of from 2.5 to 3.8, preferably from 2.7 to 3.5, still more preferably from 2.9 to 3.2, thereby forming an acidic mixture. The pH may be adjusted by the addition of any edible acidifying agents known to those skilled in the art. Examples of acidifying agents useful in the present invention include, but are not limited to, phosphoric acid and hydrochloric acid, with phosphoric acid being plef~lled.
Of course, the amount of acidifying agent added to the inactivated mixture will be known to those skilled in the art as that amount n~ces~ry to achieve the desired pH.
The adjustment of the pH of the inactivated mixture is carried out in conjunction with h~ting The temperature of the inactivated mixture during the pH adjustment is m~int~ined in the range of from 70C to 1 00C, more preferably from 80C to 90C.
The acidic mixture is then heated in a final heating stage at a temperature and for a period of time sufficient to provide a composition which improves the palatability of animal food when combined thc~ . In this final heating stage the acidic llli~ is preferably heated at a telllp~ld~ in the range of from 75C to 99C, more preferably from 80C to 95C, still more preferably from 85C to 90C, for a period of time in the range of from 1 to 20 24 hours, more preferably from 5 to 15 hours, still more preferably from 8 to 12 hours. As with the initial heating stage, this final heating stage may also involve m~i"l~inil~g the telllpc;ld~lre of the acidic mixture at an already elevated level, for example by insulating the reaction vessel.
The final palatability improving composition prepared by this process has been shown 25 to improve the palatability of animal feed when combined with said animal feed. While not inten-ling to be bound by theory, it is surprising and unexpected that the particular heating, pH adjustment, and further heating of the hydrolyzed proteinaceous material of the present invention, in the sequence provided in the present invention, can provide a palatability-wo 95/21540 2 1 ~ 8 7 ~ 2 PCT/US95/01510 improving composition. It has been found that this palatability-improving composition has palatability-improving properties superior to compositions COI~ g hydrolyzed ploleinaceous material prepared by methods which do not include the particular pH and - heating sequence of present invention.
S In a more ~,cfe.,cd embotliment in the process of the present invention the initial heating stage, the acidic mixture forming stage, and the final heating stage are carried out in the presence of air.
By the term "in the presence ofl', it is meant that air is brought into contact with the le~ccli~e mixtures of each of these stages. The air may be brought into contact with the respective lllixlules by any means known to those skilled in the art, for example by bubbling the air through the respective llliXLul. s. Note should be taken, however, that is not plcfe~cd to have the reaction exposed to the open atmosphere. This ~limini~hes the performance of the palatability-improving composition prepared by the process of the present invention. It is believed that this (limini~hment in performance is caused by the vol~tili7~tion of flavor-improving components produced by the process of the present invention. Preferred is when the reaction is carried in out in an enclosed vessel with excess air present.
While not intçn-ling to be bound by theory, it is believed that the oxygen present in the air acts to oxidize off-odor agents contained in the lc~l~e~ e llliXlUl~S. As will be appreciated by one skilled in the art, the necessA. y amount of air is that amount sufficient to oxidize the off-odor reagents present in the respective mixtures.
In a still more ~lc~.,cd embodiment of the present invention, the process for prepA~ g the palatability improving composition comprises:
(a) plcl~ing an initial lllixlure comprising from 40% to 60% by weight chicken viscera, from 40% to 60% by weight beef livers, and from 0.1% to 0.5% by weight protease, wherein said weight percentage are expressed as a percentage of the initial mixture, (b) hydrolyzing the protein contained in the chicken viscera and beef livers by reacting the protease with said protein in the presence of air and at a temperature in the range of from 55C to 65C for a period of time in the range of from 30 to 120 minlltçs, thereby forming a hydrolyzed mixture;
(c) inactivating the protease in the hydrolyzed mixture by heating the hydrolyzed mixture to a temperature of at least 90C, thereby forming an inactivated mixture;
(d) heating or m~ t~il,i"g the inactivated mixture in an initial heating stage to a temperature in the range of from 87C to 92C for a period of time in the range of from 30 to 60 minutes;
(e) following the initial heating stage, adjusting the pH of the inactivated lllixlul~
to within the range of from 2.9 to 3.2 while Il~ ing the telll~cl~lule of the inactivated mixture in the range of from 80C to 90C, thereby forming an acidic mixture; and (f) heating or m~il.l;1il-il~g the acidic mixture in a final heating stage at a temperature in the range of from 85C to 90C for a period of time in the range of from 8 to 12 hours, thereby forming a palatability-improving composition.
The present invention further relates to a product for improving the palatability of animal food, wherein said product is ~lepa~ed by the process compri~ing:
(a) I.lep~;ng an initial lllixlulc comprising a proteinaceous m~ttori~l and a protein-hydrolyzing enzyme, wherein said protein-hydrolyzing enzyme comprises from 0.01% to 0.5% by weight of said initial lllixlule;
(b) hydrolyzing the protein contained in the proteinaceous material of the initial mixture, thereby forming a hydrolyzed mixture, wherein said hydrolysis is carried out under conditions sufficient to hydrolyze a sufficient amount of protein to improve the palatability of an animal food when the composition resulting from step (f) of this process is combined with said animal food;
(c) inactivating the protein-hydrolyzing enzyme contained in the hydrolyzed mixture, thereby forming an inactivated-mixture;

wo 95/215~0 21 S 8 7 5 ~ PCT/US95/01510 (d) heating or m~ t~ il-g the inactivated mixture in an initial heating stage at a t~ ,cldl~ue in the range of from 80C to 100C for a period of time in the range of from 10 to 300 min~ltçs;
(e) following the initial heating stage, adjusting the pH of the inactivated mixture to within the range of from 2.8 to 3.8 while m~int~ining the tell~eld~ule of theinactivated mixture in the range of from 80C to 100C, thereby forming an acidic mixture, and (f) heating or m~ L;1ini~g the acidic mixture in a final heating stage at a telllpeldLul~ and for a period of time sufficient to provide a composition whichimproves the palatability of animal food when combined therewith, thereby producing a palatability improving composition.
The present invention also provides for an animal food composition having improved palatability, wherein said animal food composition comprises animal food and a palatability-improving composition. The palatability improving composition is prepared by the process 15 comprising:
(a) IJ~ep~ing an initial mixture comprising a proteinaceous material and a protein-hydrolyzing enzyme, wherein said protein-hydrolyzing enzyme comprises from 0.01% to 0.5% by weight of said initial mixture;
(b) hydrolyzing the protein contained in the proteinaceous material of the initial mixture, thereby forming a hydrolyzed mixture, wherein said hydrolysis is carried out under conditions sufficient to hydrolyze a sufficient amount of protein to improve the palatability of an animal food when the composition resulting from step (f) of this process is combined with said animal food;
(c) inactivating the protein-hydrolyzing enzyme contained in the hydrolyzed mixture, thereby forming an inactivated-mixture, (d) heating or maintaining the inactivated mixture in an initial heating stage at a temperature in the range of from 80C to 100C for a period of time in the range of from 10 to 300 minutes;

2~j8~2' 14 (e) following the initial heating stage, adjusting the pH of the inactivated mixture to within the range of from 2.8 to 3.8 while m~int~ining the temperature of the inactivated mixture in the range of from 80C to 100C, thereby forming an acidic mixture; and S (f) heating or m~ y the acidic nlixlule in a final heating stage at a temperature and for a period of time sufficient to provide a composition which - improves the palatability of animal food when combined therewith, thereby producing a palatability improving composition.
A prefelled animal feèd composition according to the present invention comprises10 animal food and a palatability-improving composition, wherein the palatability-improving composition is prepared by the process comprising:
(a) plc~;ng an initial lllixLule comprising from 40% to 60% by weight chicken viscera, from 40% to 60% by weight beef livers, and from 0.1% to 0.5% by weight protease, wherein said weight percentage are expressed as a percentage of the initial mixture;
(b) hydrolyzing the protein contained in the chicken viscera and beef livers by reacting the protease with said protein in the presence of air and at a tellll~ldlule in the range of from 55C to 65C for a period of time in the range of from 30 to 120 minutes, thereby forming a hydrolyzed mixture;
(c) inactivating the protease in the hydrolyzed mixture by heating the hydrolyzed mixture to a temperature of at least 90C, thereby forming an inactivated mixture;
(d) heating or m~ it~ g the inactivated mixture in an initial heating stage to a temperature in the range of from 87C to 92C for a period of time in the range of from 30 to 60 minutes;
(e) following the initial heating stage, adjusting the pH of the inactivated mixture to within the range of from 2.9 to 3.2 while m~int~ining the temperature of the WO 95/21540 2 i ~ ~ 7 ~ 2 PCT/US95/01510 inactivated mixture in the range of from 80C to 90C, thereby forming an acidic mixture; and (f) heating or m~int~ining the acidic mixture in a final heating stage at a temperature in the range of from 85C to 90C for a period of time in the S range of from 8 to 12 hours, thereby forming a palatability-improving composition.
The animal feed composition comprises animal feed, preferably from 85% to 98%, more preferably from 90% to 97%, still more preferably from 95% to 97% by weight animal feed, and a sufficient amount of palatability-improving composition to improve the palatability ofthe animal feed, preferably from 1% to 15%, more preferably from 2% to 10%, still more preferably from 2.5% to 5% by weight palatability-improving composition.
The present invention further provides a process for improving the palatability of an animal food composition. The process comprises:
(a) initially pre~ g a palatability-enhancing composition by the process 1 5 comprising:
(1) preparing an initial llliXLUlt~ comprising a proteinaceous material and a protein-hydrolyzing enzyme, wherein said protein-hydrolyzing enzyme comprises from 0.01% to 0.5% by weight of said initial mixture;
(2) hydrolyzing the protein contained in the proteinaceous material of the initial mixture, thereby forming a hydrolyzed mixture, wherein said hydrolysis is carried out under conditions sufficient to hydrolyze a sufficient amount of protein to improve the palatability of an animal food when the composition resulting from step (a)(6) of this process is combined with said animal food;

(3) inactivating the protein-hydrolyzing enzyme contained in the hydrolyzed mixture, thereby forming an inactivated-mixture;

2 ~S 8rt ~ PCT/US9S/Ol~S10 (4) heating or m~int~ining the inactivated mixture in an initial heating stage at a temperature in the range of from 80C to 1 00C for a period of time in the range of from 10 to 300 minutes;

(5) following the initial heating stage, adjusting the pH of the inactivated mixture to within the range of from 2.8 to 3.8 while m~ g the temperature of the inactivated mixture in the range of from 80C to 1 00C, thereby forming an acidic mixture;

(6) heating or m~ i-lillg the acidic mixture in a final heating stage at a te~l~peld~llre and for a period of time sufficient to provide a composition which improves the palatability of animal food when combined therewith, thereby producing a palatability improving composition; and (b) incorporating the palatability-improving composition into the animal food in an amount effective to increase the palatability.
The final animal food/palatability-improving composition mixture is as already described herein.
The palatability-improving composition can be incorporated into the animal food in any suitable matter. Thus, where the complete animal food or portion thereof is conditioned, the palatability-improving composition is incorporated by producing it in situ. Or, the palatability-improving composition can be prepared separately from the animal food and then mixed with or applied to the animal food.
Application of the palatability-improving composition to dry animal food by spraying is preferred for dry animal food because it allows uniform surface application without breaking the emulsion. This makes it possible to obtain improved palatability with significantly smaller amounts of the palatability-improving composition. One suitable device for spraying the emulsion to the animal food is a spray nozzle of the kind commonly employed in spray painting.

wo 95/21510 21~ g ~ S 2 pcTlus95/ol5ln The palatability-improving composition can be in an emulsified state for incorporation into the animal food. In fact, when initially prepared by the process described herein, it is contained in an emulsified state.
The palatability-improving composition prepared in this matter is generally applied in 5 any effective amount to improve the palatability of the animal food. It has been found in practice that amounts as low as 0.1% by weight, based on the total weight on the animal food, has provided sufficient improvement in palatability for dogs. Generally, amounts of greater than 5% of weight based on the total weight of the animal food are not employed unless the animal food so treated is later diluted with another material such as untreated animal food, 10 meats scraps, water, or the like.
Another method of incorporating the palatability-improving composition of the present invention is to mix it directly with other ingredients in the plep~ ions of the animal food. For example, the palatability-improving composition is admixed with other ingredients of animal food such as fat, carbohydrates, protein, vitamins and minerals, in any effective 15 amount to provide an animal food of improved palatability. The palatability-improving composition can generally comprise from 1 to 35%, preferably from 5 to 20%, of the animal food. As a guideline to an upper limit, it is noted that high concentrations seem to adversely affect the texture of the animal food, and should be avoided where the i~p~i.."ent of the texture outweighs the improvement in palatability.
While the palatability-improving composition prepared according to the present invention can improve the palatability of animal foods generally, they are especially suitable for use with nutritionally balanced comprising protein, fat, carbohydrates, vitamins and minerals.
The present invention is further illustrated, but not limited by, the following examples.
EXAMPLES
Example I
A mixture of meat is prepared by grinding to a 0.32 cm. size the following material:
(1) 34.02 kg. chicken viscera, (2) 6.80 kg. mechanically deboned beef, and (3) 6.80 kg. of W0 95/21540 2 ~ h PCT/US95/OlS10 beef liver. This mixture is conveyed to a jacketed vessel of sufficient volume to hold the mixture to an 80% capacity The material is heated to 60C by circulating a hot water bath in the jacket of the vessel. The material is agitated during this heating period.
When the mixture te~ )eldLu~e reaches 60C, 0.23 kg. of Alk~l~ce 0.6L enzyme is added to the mixture. While m~ g a t~lllpeldlule of 60C, the mixture is continuously ~git~tecl by a rotating scraped surface agitator as well as by being pumped continuously through a recirculating shear pump. The agitation and recirculation assure that the llliX~Ul~ iS
well mixed.
After 60 minlltes of heàting and agitation, steam is circulated through the jacket of the vessel to heat the mixture to a temperature of 90C. The mixture temperature is m~int~ined at this level for 60 minlltes This inactivates the enzyme and preheats the mixture for the next processing step. At this point the mixture is in the form of what is commonly referred to as a "digest."
The llliX~Ule iS next allowed to cool moderately while being pumped to another closed vessel. This holding vessel is sufficiently large to hold the llliX~Ule to a capacity of no more than 80% full. The mixture is allowed to cool to a telllpeldlure of 70C. 1.81 kg. of Phosphoric acid is added to the mixture, which adjusts the mixture pH to 3.0 While the acid is added, the mixture is continuously agitated by a scrape-surface agitator. The total acid addition time is no more than 15 minutes.
After the acid is added, the mixture is heated to a temperature of 85C. The 85C
telllpeld~lre is m~int~ined for a period of 10 hours by circulating hot water around the jacket of the holding vessel. The mixture is agitated during the 10 hour heating period.
The lllix~ure is next sprayed onto pet food kibbles in a continuous-flowing coating reel. The digest is added along with choice white grease at a l:l ratio, and this mixture is added to dry kibbles at a total concentration of 5%. The final kibble formula has a digest concentration of 2.5%, a grease level of 2.5%, a moisture of 10% and a dry solids content of approximately 90%.
Example 2 ~VO 95/2 1540 21~ ~ 7 5 2 PCT/US95/0 1510 A mixture of meat is prepared by grinding to a 0.32 cm. size the following material:
(1) 38.56 kg. poultry-by-product, (2) 6.80 kg. of beef liver. This mixture is conveyed to a jacketed vessel of sufficient volume to hold the llliXlUlt~ to an 80% capacity The material is heated to 60C by circulating a hot water bath in the jacket of the vessel. The material is ~git~ted during this heating period.
When the mixture tt;lllp~dL~e reaches 60C, 0.23 kg. of .Alk~l~ce 0.6L enzyme isadded to the mixture. While m~ g a t~",pe,dlu~e of 60C, the lllixlule is continuously agitated by a rotating scraped surface agitator as well as by being pumped continuously through a recirculating shear pump. The agitation and recirculation assure that the mixture is well mixed.
After 60 minutes of heating and agitation, steam is circulated through the jacket of the vessel to heat the mixture to a temperature of 90C. The mixture te~ e~dlu~e is m~int~ined at this level for 30 minutes. This inactivates the enzyme and preheats the mixture for the next processing step. At this point the mixture is in the form of what is commonly referred to as a 1 5 "digest."
The mixture is next allowed to cool moderately while being pumped to another closed vessel. This holding vessel is sufficiently large to hold the mixture to a capacity of no more than 80% full. The mixture is allowed to cool to a telll~ lul~ of 70C. 1.81 kg. of Phosphoric acid is added to the mixture, which adjusts the mixture pH to 3.0 While the acid is added, the mixture is continuously agitated by a scrape-surface agitator. The total acid addition time is no more than 15 minutes.
After the acid is added, the mixture is heated to a temperature of 85C. The 85C
tellly~ldlule is m~int~ined for a period of 5 hours by circulating hot water around the jacket of the holding vessel. The mixture is agitated during the 5 hour heating period.
The mixture is next sprayed onto pet food kibbles in a continuous-flowing coating reel. The digest is added along with choice white grease at a 5:6 ratio, and this mixture is added to dry kibbles at a total concentration of 11%. The final kibble formula has a digest WO 95/2154() PCT/US95/01510 21~8~ 20 concentration of 5%, a grease level of 6%, a moisture of 10% and a dry solids content of approximately 90%.
Example 3 A mixture of meat is plepaled by grinding to a 0.32 cm. size the following material:
(1) 34.02 kg. chicken viscera, (2) 11.34 kg. of beef liver. This lllixlul~ is conveyed to a jacketed vessel of sufficient volume to hold the mixture to an 80% capacity The material is heated to 60C by circ~ ting a hot water bath in the jacket of the vessel. The material is agitated during this heating period.
When the mixture tell~ dl~ue reaches 60C, 0.05 kg. of ~lk~ e 0.6L enzyme is 10 added to the mixture. While m~int~ining a temperature of 60C, the mixture is continuously agitated by a rotating scraped surface agitator as well as by being pumped continuously through a recirculating shear pump. The agitation and recirculation assure that the mixture is well mixed.
After 30 minutes of heating and agitation, steam is circulated through the jacket of the 15 vessel to heat the lllixlu~e to a temperature of 90C. The mixture temperature is m~int~ined at this level for 30 minutes. This inactivates the enzyme and preheats the mixture for the next proces~ing step. At this point the mixture is in the form of what is commonly referred to as a "digest."
The mixture is next allowed to cool moderately while being pumped to another closed 20 vessel. This holding vessel is sufficiently large to hold the mixture to a capacity of no more than 80% full. The mixture is allowed to cool to a telllpcldl~lre of 70C. 1.81 kg. of Phosphoric acid is added to the mixture, which adjusts the mixture pH to 3.0 While the acid is added, the mixture is continuously agitated by a scrape-surface agitator. The total acid addition time is no more than 15 minutes.
After the acid is added. the IlliX~ iS heated to a temperature of 85C. The 85Ctemperature is m~int~ined for a period of 7 hours by circulating hot water around the jacket of the holding vessel. The mixture is agitated during the 5 hour heating period.

wo 95/215~0 2 ~ 5 ~ 7 ~ 2 PCT/US9S/015 10 The mixture is next sprayed onto pet food kibbles in a continuous-flowing coating reel. The digest is added along with choice white grease at a 1:1 ratio, and this mixture is added to dry kibbles at a total concentration of 5%. The final kibble formula has a digest concentration of 2.5%, a grease level of 2.5%, a moisture of 10% and a dry solids content of 5 approximately 90%.
Fx~le 4 A mixture of meat is prepared by grinding to a 0.32 cm. size 22.68 kg. chicken necks and backs and 22.68 kg. of mechanically deboned beef. This lllixlule is conveyed to a jacketed vessel of sufficient volume to hold the lllixlule to an 80% capacity The material is 10 heated to 60C by circulating a hot water bath in the jacket of the vessel. The material is agitated during this heating period.
When the lnixlule telllp~;ldlule reaches 60C, 0.23 kg. of Alkalase 0.6L enzyme is added to the lllixlule. While m~;"t~ g a t~lllp~ldlule of 60C, the mixture is continuously agitated by a rotating scraped surface agitator, as well as by being pumped continuously 15 through a recirculating shear pump. The agitation and recirculation assure that the mixture is well mixed.
After 60 minutes of heating and agitation, steam is circulated through the jacket of the vessel to heat the mixture to a telllp~,ldlu~c; of 90C. The lllixlule t~ll~eldlllre is m~int~ined at this level for 10 minutes This inactivates the enzyme and preheats the mixture for the next 20 processing step. At this point the mixture is in the form of what is commonly referred to as a "digest."
The mixture is next allowed to cool moderately while being pumped to another closed vessel. This holding vessel is sufficiently large to hold the mixture to a capacity of no more than 80% full. The mixture is allowed to cool to a temperature of 70C. 0.23 kg. of 25 Phosphoric acid is added to the mixture, which lowers the mixture pH slightly to approximately 6.0 While the acid is added, the mixture is continuously agitated by a scrape-surface agitator. The total acid addition time is no more than 15 minutes.

2~ 22 After the acid is added, the mixture is heated to a temperature of 85C. The 85C
te~l~pe,dl~lre is m~int~ined for a period of 1/2 hour by circulating hot water around the jacket of the holding vessel. The mixture is agitated during the 1/2 hour heating period. This acidified digest is pumped continuously from the holding tank to a extrusion process as described below.
The acidified digest is added continuously to a preconditioner. A dry mixture con~i~ting of 40% ground corn, 27% wheat, 27% soy, and 6% other vitamin and mineral materials, is also fed to the preconditioner, along with the acidified digest. The ratio of acidified digest to dry mixture being fed to the preconditioner is approximately 1 :4 (acidified 10 digest:dry mixture). As the dry llli~lu~e is blended with the acidified digest, water and stearn are added to the contents of the preconditioner. This brings the total moisture of the mixture to 20 to 25% (including the moisture which exists as part of the dry mixture's natural content). The mean residence time of the resulting wet dough in the preconditioner is appro~i",ately 2 to S minutes.
The wet dough is next transferred to an Anderson extruder. The extruder has a 7.62 cm. diameter and a typical screw profile suitable for extruding pet food. Water and steam are added to the extrudate in the barrel of the extruder. The extruder screw rotates at 150 rpm and produces kibbles at a rate of 250 kg. per hour. The final extrudate has a moisture content of 25 to 35% (wet basis) and a t~ c~dl~lre of no less than 120C.
Kibbles are produced by extruding the wet dough through a die consisting of 10 openings, all of which have the same shape. As the dough exits the extruder through the die, it is pelleted continuously by a fly-knife cutter. Kibbles exiting the extruder are transferred directly to a dryer, where they are dried to a moisture of 8% to 10% wet basis.
The dry kibbles are next enrobed with a mixture of the digest and choice white grease.
25 The digest and choice white grease mixture is sprayed onto the kibbles in a continuous-flowing coating reel. The ratio of digest to choice white grease is 1 :1, and this mixture is added to dry kibbles at a total concentration of 5%. The final kibble formula has a digest WO 95/21540 PCT/US95/01!;10 22f c~ 8 7~ ~

concentration of 2.5%, a grease level of 2.5%, a moisture content of 10% and a dry solids content of approximately 90%.

Claims (5)

WHAT IS CLAIMED IS:

1. A process for preparing a composition for improving the palatability of animal food, said process comprising:
(a) preparing an initial mixture comprising a proteinaceous material and a protein-hydrolyzing enzyme, wherein said protein-hydrolyzing enzyme comprises from 0.01% to 0.5% by weight of said initial mixture;
(b) hydrolyzing the protein contained in the proteinaceous material of the initial mixture, thereby forming a hydrolyzed mixture, wherein said hydrolysis is carried out under conditions sufficient to hydrolyze a sufficient amount of protein to improve the palatability of an animal food when the composition resulting from step (f) of this process is combined with said animal food;
(c) inactivating the protein-hydrolyzing enzyme contained in the hydrolyzed mixture, thereby forming an inactivated-mixture;
(d) heating or maintaining the inactivated mixture in an initial heating stage at a temperature in the range of from 80°C to 100°C for a period of time in the range of from 10 to 300 minutes;
(e) following the initial heating stage, adjusting the pH of the inactivated mixture to within the range of from 2.8 to 3.8 while maintaining the temperature of the inactivated mixture in the range of from 80°C to 100°C, thereby forming an acidic mixture; and (f) heating or maintaining the acidic mixture in a final heating stage at a temperature and for a period of time sufficient to provide a composition which improves the palatability of animal food when combined therewith, thereby producing a palatability improving composition.

2. A process according to claim 1 wherein the proteinaceous material is selected from the group consisting of meat, soy products, whey, chicken skins, cheese, gluten, meat by-products, animal offal, poultry by-products, brewer's yeast, and mixtures thereof; wherein the protein-hydrolyzing enzyme is provided to the initial mixture by the addition of protease;
wherein the protein-hydrolyzing enzyme comprises from 0.01% to 0.75% by weight of the initial mixture; wherein the initial mixture is reacted at a temperature in the range of from 45°C to 75°C for a period of time in the range of from 15 to 120 minutes; wherein the protein-hydrolyzing enzyme contained in the hydrolyzed mixture is inactivated by heating the hydrolyzed mixture to a temperature of at least 85°C; wherein the inactivated mixture is heated in the initial heating stage at a temperature in the range of from 85°C to 95°C for a period of time in the range of from 15 to 120 mixtures; wherein the pH of the acidic mixture is within the range of from 2.7 to 3.5 while maintaining the temperature of the inactivated mixture in the range of from 80°C to 90°C; and wherein the acidic mixture is heated in the final heating stage at a temperature in the range of from 80°C to 95°C for a period of time in the range of from 5 to 15 hours.

3. A process for preparing a composition for improving the palatability of animal food, said process comprising:
(a) preparing an initial mixture comprising from 40% to 60% by weight chicken viscera, from 40% to 60% by weight beef livers, and from 0.1% to 0.5% by weight protease, wherein said weight percentage are expressed as a percentage of the initial mixture;
(b) hydrolyzing the protein contained in the chicken viscera and beef livers by reacting the protease with said protein in the presence of air and at a temperature in the range of from 55°C to 65°C for a period of time in the range of from 30 to 120 minutes, thereby forming a hydrolyzed mixture;
(c) inactivating the protease in the hydrolyzed mixture by heating the hydrolyzed mixture to a temperature of at least 90°C, thereby forming an inactivatedmixture;

(d) heating or maintaining the inactivated mixture in an initial heating stage to a temperature in the range of from 87°C to 92°C for a period of time in the range of from 30 to 60 minutes;
(e) following the initial heating stage, adjusting the pH of the inactivated mixture to within the range of from 2.9 to 3.2 while maintaining the temperature of the inactivated mixture in the range of from 80°C to 90°C, thereby forming an acidic mixture; and (f) heating or maintaining the acidic mixture in a final heating stage at a temperature in the range of from 85°C to 90°C for a period of time in the range of from 8 to 12 hours, thereby forming a palatability-improving composition.

4. A process for improving the palatability of an animal food which comprises:
(a) initially preparing a palatability-enhancing composition by the process comprising:
(1) preparing an initial mixture comprising a proteinaceous material and a protein-hydrolyzing enzyme, wherein said protein-hydrolyzing enzyme comprises from 0.01% to 0.5% by weight of said initial mixture;
(2) hydrolyzing the protein contained in the proteinaceous material of the initial mixture, thereby forming a hydrolyzed mixture, wherein said hydrolysis is carried out under conditions sufficient to hydrolyze a sufficient amount of protein to improve the palatability of an animal food when the composition resulting from step (a)(6) of this process is combined with said animal food;
(3) inactivating the protein-hydrolyzing enzyme contained in the hydrolyzed mixture, thereby forming an inactivated-mixture;

(4) heating or maintaining the inactivated mixture in an initial heating stage at a temperature in the range of from 80°C to 100°C for a period of time in the range of from 10 to 300 minutes;
(5) following the initial heating stage, adjusting the pH of the inactivated mixture to within the range of from 2.8 to 3.8 while maintaining the temperature of the inactivated mixture in the range of from 80°C to 100°C, thereby forming an acidic mixture;
(6) heating or maintaining the acidic mixture in a final heating stage at a temperature and for a period of time sufficient to provide a composition which improves the palatability of animal food when combined therewith, thereby producing a palatability improving composition; and (b) incorporating the palatability-enhancing composition into the animal food inan amount effective to increase the palatability of the animal food.

5. A process according to claim 4 wherein the animal food is a dog food; wherein the palatability-enhancing composition is incorporated into the animal food by admixing it in-situ with other ingredients of animal food such as fat, carbohydrates, protein, vitamins and minerals, in any effective amount to provide an animal food of improved palatability; and wherein the palatability improving composition employed in the amount of from 5% to 20%, based on the weight of the animal food.