CA2576062A1

CA2576062A1 - Pet food compositions having a defined relaxation property

Info

Publication number: CA2576062A1
Application number: CA002576062A
Authority: CA
Inventors: Thomas Edward Huetter; Jeffrey Scott Lang; Prasad Venkat Gopalkrishnan; Lee P Randall
Original assignee: Individual
Current assignee: Dads Pet Care Inc
Priority date: 2004-08-12
Filing date: 2005-08-12
Publication date: 2006-02-23
Also published as: WO2006020886A1; AR050210A1; EP1784084A1; MX2007001721A; CN101068473A; AU2005272648A1; JP2008508902A; BRPI0514260A

Abstract

Disclosed herein are pet food compositions exhibiting a defined Maximum Relaxation Force and Maximum Relaxation Stress. The pet food compositions exhibit prolonged chew time by the pet. In optional embodiments, the pet food compositions comprise one or more of water, humectant, a grain source, or a cross-linking agent.

Description

FIELD OF THE INVENTION
The present invention is directed to pet food compositions having a defined property which is believed to correlate with the length of time necessary for a pet to chew the composition.

BACKGROUND OF THE INVENTION
Known pet food compositions are available in a variety of forms and textures.
Most of these pet food compositions tend to be inflexible, such as extruded pet food kibbles which are efficiently chewed and consumed by the pet. Depending upon the intended use or function of the composition, inflexibility may be a property which is desirable or undesirable. For example, kibbles provide the desirable advantage of enabling a pet to easily consume a nutritionally balanced food, such as to provide the nutrients necessary to sustain life. As another example, crunchy treats, also easily consumed, are efficient forms useful to responsively reward positive behavior.
It is advantageous, however, to provide pet food compositions which are less efficiently chewed by the pet. These compositions may be useful for a variety of purposes. For example, prolonged chewing action may result in advantageous mechanical cleaning of the teeth through consistent and prolonged contact with the teeth or extended release of any therapeutic actives. Additionally or alternatively, behavioral issues such as continuous chewing of inappropriate objects may be ameliorated through prolonged enjoyment (through chewing) of the composition.
Unfortunately, known chews tend to be consumed by a pet more quickly than would be desirable to achieve the above stated purposes or, alternatively or additionally, known chews are hard or brittle. Still further, other known chews contain significant levels of rawhide, or are wholly made of rawhide, which is undesirable for a pet in view of issues associated with compromised digestibility of the rawhide (which can result in vomiting by the pet).
The present inventors have discovered pet food compositions that exhibit properties which, without being limited by theory, are believed to correlate with the length of tiine necessary for a pet to chew the composition, while still exhibiting a flexibility not exhibited by hard or brittle compositions. In view of this discovery, the inventors are now able to provide pet food compositions that may achieve the purposes set forth above, thereby optionally providing certain benefits such as mechanical cleaning of the teeth, extended release of any therapeutic actives, or amelioration of behavioral issues. These and other benefits of the present invention are described herein.
SUMMARY OF THE INVENTI N
Disclosed herein are pet food compositions exhibiting a defined Maximum Relaication Stress and a Maximum Relaxation Force. In particular, the pet food compositions exliibit a Maximum Relaxation Force of at least about 2.5 MPa. In particular, the pet food compositions exhibit a Maximum Relaxation Force of at least about 1 kN. The pet food compositions exhibit prolonged chew time by the pet.
BRIEF DESCRIPTION OF THE FIGURES
Figure 1 indicates a plot of force (in kN) versus time (in seconds) for three illustrative, inventive pet food compositions tested in accordance with the Maximum Relaxation Force methodology described in detail herein.
Figure 2 indicates sample contrast brought out in terms of geometry-independent stress measurements i.e. Maximum Relaxation Stress (MPa) so as to be able to compare samples of different dimensions.
DETAILED DESCRIPTION OF THE INVENTION
Various documents including, for example, publications and patents, may be recited throughout this disclosure. All such documents are hereby incorporated by reference. The citation of any given document is not to be construed as an admission that it is prior art with respect to the present invention.
All percentages and ratios are calculated by weight unless otherwise indicated.
All percentages and ratios are calculated based on the total composition unless otherwise indicated.
The compositions herein may comprise, consist essentially of, or consist of any of the features or embodiments as described herein.
While various embodiments and individual features of the present invention have been illustrated and described, various other changes and modifications can be made without departing from the spirit and scope of the invention. As will also be apparent, all combinations of the embodiments and features taught in the foregoing disclosure are possible and can result in preferred executions of the invention.
As used herein, the term "pet" means a domestic animal preferably including (for example) a dog, cat, horse, cow, pig, rabbit, and the like. Domestic dogs and cats, particularly dogs, are particularly preferred pets.
THE COMPOSITIONS OF THE PRESENT INVENTION
The pet food compositions described herein may be useful for a variety of purposes. It is believed that prolonged chew time is particularly advantageous for a variety of reasons including, for example, enhanced contact with the teeth, thereby providing the opportunity for advantageous mechanical cleaning of the teeth (particularly wherein brushing or other preventative measures are not desirable or practical), extended release of any therapeutic actives, or prolonged enjoyment of the composition (which may lead to general well-being of the pet or distraction from disruptive behaviors such as chewing household articles not intended for such chewing).
Without intending to be limited by theory, it is believed that prolongation of chew time by the pet correlates with a particular property of the composition, related to springiness or resilience of the composition, which for convenience herein is described as the 'relaxation' of the composition. It is therefore believed that such relaxation may be characterized as one factor which represents 'chewiness' of a composition.
Again without limitation by theory, it is the enhanced relaxation strength of the pet food composition, as defined herein by the Maximum Relaxation Force and/or Maximum Relaxation Stress, which is believed to correlate with a prolonged chew time of the composition when consumed by the pet. Based on this believed correlation, the inventors herein have characterized the present compositions in relation to the relaxation force characteristic, defined herein for convenience as the Maximum Relaxation Force exhibited by the compositions.
It is found that, by virtue of the Maximum Relaxation Force defined herein, a single serving of the pet food compositions herein (for example, having a mass of from about 15 grams to about 70 grams) may optionally be consumed by the pet over a period of at least about 5 minutes, or at least about 10 minutes, or at least about 20 minutes, or at least about 30 minutes. Pets of relatively small size, such as small breed dogs, may tend to consuine the pet food composition over a longer period of time relative to those of relatively larger size.
The pet food compositions exhibit a Maximum Relaxation Force of at least about 1 k1~1, preferably at least about 1.5 kN, more preferably at least about 1.8 kN, still even more preferably at least about 2 kN, still even more preferably at least about 2.5 kN.
The pet food compositions exhibit a Maximum Relaxation Stress of at least about 2.5 MPa, preferably at least about 2.8 MPa,-more-preferably at least about 3 MPa, even more preferably at least about 3.5 MPa.
The pet food compositions herein are adapted for use by a pet. In this respect, as will be well understood by the ordinarily skilled artisan, the primary use of the compositions described herein is for use by a pet and the compositions are therefore formulated for such use. As used herein, the term "pet food composition" means a composition that is intended for ingestion by a pet. These will advantageously include foods intended to supply necessary dietary requirements (such as nutritionally balanced foods (those composition having known required nutrients to sustain life in proper amounts and proportion based on recommendations of recognized authorities in the field of pet nutrition)), as well as supplements as used herein means treats and/or chews. As one of ordinary skill will recognize in view of this disclosure, the pet food compositions are advantageously chews for pets such as dogs, wherein the prolonged chew time imparted by the composition as exhibited by the Maximum Relaxation Force (as described more fully herein below) and the Maximum Relaxation Stress (as described more fully herein below) provides advantageous mechanical cleaning of the teeth, extended release of any therapeutic actives, prolonged enjoyment of the composition, or the like.
Non-limiting examples of these pet food compositions are those which may be classified as chews in the pet food industry, intended for prolonged chewing by the pet.
Chews can be provided in a variety of forms, including those prepared by baking, extrusion, injection molding, transfer molding, and/or compression molding.
Chewing action allows the pet to softly penetrate the chewable composition, promoting for example, clean, healthy teeth and/or fresh breath.
The pet food compositions may comprise any of a variety of components, provided that the compositions exhibit the defined Maximum Relaxation Force and/or Maxinluin Relaxation Stress. Without intending to be limited by theory, it is believed that compositions exhibiting such Maxinium Relaxation Force and/ or Maximum Relaxation Stress may optionally comprise water, humectant, a legume source, a grain source, or a cross-linking agent and, as such, the pet food compositions herein optionally comprise at least one of such components or such other components providing compositions exhibiting the defined Maximum Relaxation Force and/or Maximum Relaxation Stress. These and other optional components of the present pet food compositions are described as follows:
In an optional embodiment herein, the pet food composition coniprises at least one humectant. Without intending to be limited by theory, it is believed that the presence of one or more humectants contributes to the ability of the composition to retain water (moisture), which further contributes to the relaxation of the compositions, and therefore believed correlation with chew time. Humectants are widely known in the art, such as those selected from polyhydric alcohols (e.g., glycerol (also often referenced as glycerin), propylene glycol, glycerol diglycerol, propylene glycol, triethylene glycol, polyvinyl alcohol, polyethylene glycol, sorbitol, mannitol, maltitol, and the like), fatty acid esters (e.g., glyceryl monostearate), sugars (e.g., corn syrups, sucrose, and the like), and mixtures thereof. In one embodiment herein, the composition comprises at least one of such humectants, or at least two of such humectants. Humectants which may be particularly advantageous include polyhydric alcohols (e.g., glycerol) and sugars (e.g., corn syrup, such as high fructose corn syrup).
In an embodiment herein, the compositions may comprise at least about 1% of humectant, or at least about 10%, or at least about 15%, or at least about 20%, or at least about 25% of humectant, all optionally up to levels of about 35% or 50% of humectant, all by weight of the composition. Such levels of humectant reference the total of all humectants present in the composition.
In one embodiment herein, the pet food composition comprises water. Without intending to be limited by theory, it is believed that the presence of water at relatively elevated levels may be a factor contributing to the unique properties of the pet food compositions, in particular its ability to exhibit the relaxation properties described herein.
In an optional embodiment herein, the compositions may comprise at least about 5% water, or at least about 10%, or at least about 14%, or at least about 15%, or at least about 18%, or at least about 20 ' water, all optionally up to levels of about 25% or 30%
water, all by weight of the composition.
In an embodiment herein, the pet food compositions can exhibit a water activity (A,õ) of at least about 0.5, preferably at least about 0.6, preferably about 0.75, preferably about 0.8 water activity. Water activity is measured in accordance with techniques which are quite standard in the art. Wherein the pet food composition conlprises relatively high levels of water, it may be desirable to include one or more mold inhibitors, such as potassium sorbate, calcium propionate, or the like.
Other components optionally beneficial for inclusion in the compositions used herein include a source of protein, carbohydrate, and/or fat, preferably at least protein and carbohydrate.
Crude protein material may comprise vegetable proteins such as soybean, cottonseed, and peanut, or animal proteins such as casein, albumin, and meat protein.
Non-limiting examples of meat protein useful herein include a protein source selected from the group consisting of beef, pork, lamb, poultry, fish, vegetable, and mixtures thereof. The compositions may also contain other materials such as dried whey and other dairy by products.
Carbohydrate may be advantageously sourced through inclusion of a grain or a legume source. Without intending to be limited by theory, it is believed that the presence of such a grain may be a factor contributing to the unique properties of the pet food compositions, in particular its ability to exhibit the relaxation properties described herein.
In one embodiment herein, the pet food composition comprises at least one grain source.
Grain sources are widely known in the art, such as those selected from corn, oats, rice, milo, sorghum, barley, wheat, and mixtures thereof. In one embodiment herein, the composition may comprise at least one grain source, or at least two grain sources, or at least three grain sources.
Wheat may be advantageously utilized. Sources of wheat may include, for example, whole wheat, wheat flour, wheat gluten, wheat bran, wheat farina, wheat malt, wheat starch, and mixtures thereof, and the like. Wheat flour and wheat gluten, and mixtures thereof, may be particularly advantageous sources of wheat.
Legume sources are widely known in the art, such as soy.

In an embodiment herein, the pet food compositions may comprise one or more cross-linking agents. Without intending to be liniited by theory, it is believed that such cross-linking agent may contribute to the three-dimensional structure of the pet food composition, thereby contributing to the Maximum Relaxation Force and/or Maximum Relaxation Stress exhibited by such composition. Cross-linking agents are widely known in the art, for example, sulfur, DL-methionine, and sodium metabisulfite.
In an embodiment herein, the pet food compositions have a relatively low fat content, particularly for similar reasons related to desirability of relatively low caloric load. Fat content may be advantageously manipulated througli, for example, increasing the carbohydrate and/or protein levels relative to the fat levels. For example, optionally, the pet food compositions may be substantially free of fat, meaning comprising less than about 4% fat, by weight of the composition. In other embodiments, the pet food compositions may comprise less than about 3%, or less than about 2% fat, by weight of the composition.
In an embodiment herein, the pet food compositions have a relatively low caloric load. This may be particularly advantageous wherein the compositions are food supplements, as caloric load in addition to that provided through a complete and balanced food may be undesirable for the pet, particularly depending on the quantity of composition supplied to the pet on a daily, or other defined, basis. For example, optionally, the pet food compositions may have a caloric load of less than about 10 calories per gram of composition, or less than about 5 calories per gram of composition.
In an embodiment herein, the pet food composition comprises one or more therapeutic actives. For example, the pet food compositions may possess the ability to sequester calcium, inhibit bacterial growth, inhibit plaque, inhibit tartar (defined herein as including calculus), improve malodor of the oral cavity, or the like. The pet food compositions may be further advantageous for the inhibition of periodontal disease, gingivitis, breath odor, and the like.
In an embodiment useful for oral health, the pet food compositions may optionally comprise a soluble mineral component. As used herein, the term "soluble" with respect to the mineral component means that at least about 50% of the mineral component, by weight of the mineral component, dissolves in a sample of water (in an amount typically present during mastication) at ambient temperature. Optionally, the term "soluble" with ~
respect to the mineral component mans that at least about 75%, or at least about 90%, of the mineral component, again by weight of the mineral component dissolves in this sample of water (in an amount typically present during mastication) at 25 C.
The soluble nlineral component may be provided wherein at least a portion of the phosphate component is coated on the surface of the composition, integrated within the composition, or both.
The composition may comprise -an amount of the soluble mineral component which is an effective amount for use as an oral medicament, as has been defined herein above. As an example, the composition may optionally comprise at least about 0.01%, or at least about 0.02%, or at least about 0.05%, or at least about 0.1%, or at least about 0.15% of the mineral component, by weight of the composition. As a further example, the composition may optionally comprise from about 0.01% to about 10%, or from about 0.02% to about 5%, or from about 0.05% to about 5%, or from about 0.1% to about 2%, or from about 0.15% to about 1%, of the mineral component, by weight of the composition. Specific illustrative amounts of each mineral which may optionally be utilized in the mineral component are described below.
The soluble mineral component may optionally comprise one or more minerals selected from zinc, manganese, tin, copper, and mixtures thereof. Various embodiments described herein may, for example, comprise two or more, or three, or all four of these minerals. Moreover, the minerals from which selections may be drawn may be modified, for example wherein the minerals are selected from manganese, tin, copper, and mixtures thereof. Illustrative minerals, including exemplary sources and amounts, are described as follows:
The soluble mineral component may optionally comprise zinc. Sources of zinc which will contribute to a soluble mineral component will be well-known to those of ordinary skill in the art. Illustrative sources of zinc include zinc sulfate, zinc gluconate, zinc chloride, zinc citrate, zinc lactate, zinc malate, zinc tartrate, and mixtures thereof.
Zinc sulfate monohydrate may be a particularly useful zinc source. Zinc citrate may impart enhanced palatability relative to certain other zinc sources due to chelation with the citrate. Wherein the composition comprises zinc, the composition may optionally comprise at least about 0.001% zinc ion, at least about 0.01% zinc ion, at least about 0.05% zinc ion, or at least about 0.07% zinc ion, or at least about 0.1% zinc ion, by ~
weight of the composition. As a fiirther example, wherein the composition comprises zinc, the composition may optionally comprise from about 0.001 / to about 1%, or from about 0.005% to about 0.75%, or from about 0.05% to about 0.5%, or from about 0.1% to about 0.4% zinc ion, all by weight of the conlposition.
The soluble mineral component may optionally comprise tin. Sources of tin which will contribute to a soluble mineral component will be well-known to those of ordinary skill in the art. Illustrative sources of tin include tin lactate, tin gluconate, tin acetate, tin sulfate, tin malate, and mixtures thereof. Wherein the composition comprises tin, the composition may optionally comprise at least about 0.0001% tin ion, at least about 0.0005% tin ion, or at least about 0.001% tin ion, or at least about 0.0015% tin ion, by weight of the composition. As a further example, wherein the composition comprises tin, the composition may optionally comprise from about 0.0001% to about 0.5%, or from about 0.0005% to about 0.1%, or from about 0.001% to about 0.05%, or from about 0.001 /o to about 0.25% tin ion, all by weight of the composition.
The soluble mineral component may optionally comprise copper. Sources of copper which will contribute to a soluble mineral component will be well-known to those of ordinary skill in the art. Illustrative sources of copper include copper chloride, copper gluconate, copper sulfate, copper bisglycinate, copper lactate, copper malate, copper acetate, copper citrate, copper tartrate, and mixtures thereof. Copper gluconate is particularly preferred herein. Wherein the composition comprises copper, the composition may optionally comprise at least about 0.0005%, or at least about 0.01%, or at least about 0.015%, or at least about 0.02% copper ion, all by weight of the composition. As a further example, wherein the composition comprises copper, the composition may optionally comprise from about 0.0005% to about 0.5%, or from about 0.0005% to about 0.1%, or from about 0.01% to about 0.1%, or from about 0.015%
to about 0.05%, or from about 0.02% to about 0.25% copper ion, all by weight of the composition.
The soluble mineral component may optionally comprise manganese. Sources of manganese which will contribute to a soluble mineral component will be well-known to those of ordinary skill in the art. Illustrative sources of manganese include manganese chloride, manganese sulfate, manganese gluconate, manganese acetate, manganese malate, manganese tartrate, manganese citrate, manganese lactate, manganese glycinate, and mixtures thereof, -Manganese sulfate monohydrate may be particularly useful.
Wherein the composition comprises manganese, the composition may optionally comprise at least about 0.0001% manganese ion, or at least about 0.001%, or at least about 0.01%, or at least about 0.015%, or at least about 0.02% manganese ion, by weiglit of the composition. As a further example, wherein the composition coniprises manganese, the composition may optionally comprise from about 0.0001% to about 1 / , or from about 0.001 /o-to about 0.5%, or from about 0.01 Jo to about 0.5%, or from about 0.05% to about 0.4% manganese ion, all by weight of the composition.
In an optional embodiment herein, wherein a mineral component is used, at least a portion of the mineral component is coated on the surface of the composition.
Consistent with this embodiment, the mineral component can be provided on the surface of the composition without substantial compromise in the organoleptic, or other key properties of the composition. As such, the compositions may be satisfactorily administered to the pet while providing optimized efficacy since the mineral component is readily available and quickly solubilized in the oral cavity of the pet. In a further optional embodiment, at least about 50% of the mineral component, or at least about 75% of the mineral component, or at least about 90% of the mineral component, or at least about 95% of the mineral component, all by weight of the mineral component, is coated on the surface of the composition.
In another embodiment herein, at least a portion of the mineral component is integrated within the edible composition. This is particularly desirable in the context of this invention wherein the pet chews the composition over an extended period of time.
The inventors have discovered that, in this embodiment, efficacy is enhanced through availability of the mineral component over an extended period of time.
In another embodiment herein, the compositions may comprise a mineral component and a phosphate component. This phosphate component is not limited to the chain length of phosphate utilized; rather, the benefits of the phosphate component may be enhanced when combined with mineral component, regardless of chain length.
The composition may optionally comprise an amount of a phosphate component which is an effective amount for use as an oral medicament, as has been defined herein above.
Optionally, unlike the complexes described in U.S. Patent No. 5,000,944, the mineral component and the phosphate coniponent9 or any individual components thereof, are not present as a complex in the composition.
The phosphate component may comprise a component which contains at least 2 phosphorous atoms. Illustrative compounds which may be utilized as the phosphate component include pyrophosphates, polyphosphates, or mixtures thereof. Kirk &
Othmer, Eracycl pedicz of Chemical Technology, 2d Ed., Vol. 15 (1965), pp. 232 to 276, discloses a number of water-soluble inorganic pyrophosphate salts.
In another embodiment herein, at least a portion of the phosphate component is a pyrophosphate. For example, inorganic pyrophosphates such as alkali metal pyrophosphates including sodium acid pyrophosphate (SAPP) and tetrapotassium pyrophosphate (TKPP) may be utilized. Illustrative examples of SAPP include SAPP
having a molecular weight of about 222. Also useful may be a tetraalkali metal pyrophosphate such as tetralithium pyrophosphate. Examples of dialkaline metal pyrophosphates are dicalcium pyrophosphate, dibarium pyrophosphate, and dimagnesium pyrophosphate. Trialkali metal monoacid pyrophosphates such as trisodium hydrogen pyrophosphate may also be used.
In another embodiment, at least a portion of the phosphate component is a polyphosphate. As will be readily understood in the art, as the chain length of the polyphosphate increases, the polyphosphate is provided as multiple length species having an average chain length. Polyphosphates may also be utilized herein, such as those polyphosphates having an average chain length of 3 or greater. Examples include tripolyphosphates such as sodium tripolyphosphate (STPP), SODAPHOS (average chain length of 7), HEXAPHOS (average chain length of 13) (commercially available from FMC Corporation), other hexametaphosphate (such as, average chain length of 21), and sodium acid metaphosphate. Illustrative examples of hexametaphosphate include sodium hexametaphosphate or potassium hexametaphosphate having a molecular weight of about 2200.
The phosphate component may optionally be provided wherein at least a portion of the phosphate component is coated on the surface of the composition, at least a portion of the phosphate component is integrated within the composition, or both.
Further embodiments include those pet food compositions (for example, chews) wherein at least a portion of the mineral component is coated on the surface of the composition and at least a portion of the phosphate component is integrated within the composition, or at least a portion of the phosphate component is coated on the surface of the conlposition and at least a portion of the mineral component is integrated within the composition, or wherein at least a portion of both the mineral and phosphate components are coated on the surface of the conlposition, or wherein at least a portion of both the mineral and phosphate components are integrated within the composition.
As an example, the composition may optionally comprise at least about 0.05%, or at least about 0.1%, or at least about 0.2%, or at least about 0.5%, or at least about 1% of the phosphate component, by weight of the composition. As a further example, the composition may optionally comprise from about 0.05% to about 10%, or from about 0.1% to about 5%, from about 0.2% to about 4%, or from about 0.5% to about 4%
of the phosphate component, by weight of the composition.
In yet another embodiment, the present pet food compositions may comprise one or more fermentable fibers. The fermentable fiber may be any fiber source which intestinal bacteria present in the pet can ferment to produce short chain fatty acids or other metabolic components. Non-limiting examples of such fermentable fibers include inulin, chicory, beet pulp (from sugar beet), gum arabic, gum talha, psyllium, rice bran, carob bean gum, citrus pulp, pectin, fructooligosaccharides, galactooligosaccharide, oligofructoses, mannanoligosaccharides, soy fiber, arabinogalactan, arabinoxylan, and mixtures thereof.

As an example, the pet food composition may optionally comprise at least about 0.001 %, or at least about 0.01 %, or at least about 0.1 %, or at least about 0.5%, or at least about 1%, or at least about 2% of total fermentable fiber, all optionally up to levels of about 10%, 25%, or 50% fermentable fiber, all by weight of the composition.
In anotlier embodiment herein, the pet food compositions are substantially free of rawhide. The term "substantially free of rawhide" means that the referenced composition comprises less than about 1% rawhide, preferably less than about 0.5%, and most preferably less than about 0.2% rawhide, all by weight of the composition.
In another embodiment herein, the pet food compositions are substantially free of synthetic polymer. The term "substantially free of synthetic polymer" means that the referenced composition comprises less than about 1% synthetic polymer, preferably less than about 0.5%, and most preferably less than about 0.2% synthetic polymer, all by weight of the composition. Non-limiting examples of synthetic polymer include polyurethane, rubber, or nylon.
METH DS
MAXIMUM RELAXATION FORCE METHOD /MAXIMUM RELAXATION STRESS
CALCULATION
The Maximum Relaxation Force is determined in accordance with the following methodol-ogy:
An INSTR N Model 4502 is used for this method (herein referred to as the "INSTRON", commercially available from Instron Corporation, Canton, MA, U.S.A.).
The INSTRON is run in dynamic compression mode with a 10 kN load cell for force measurement. The upper platen moves, and the lower platen is stationary. The test samples chosen for the characterization are, if necessary, cut across the cross-section to form samples of 1 inch length each.
Relaxation measurements of a test sample are conducted at a temperature of 25 C
and a relative humidity of 30%, measured in accordance with techniques which will be quite well-known to those of ordinary skill. The INSTRON is utilized for these measurements. The INSTRON controller is turned on. The controller communicates with a personal coinputing device for data acquisition via the Series IX
software interface also available from the INSTRON Corporation. In 'Method' creation using Series IX, the personal computing device is set up for data acquisition to be initiated by the INSTRON
controller input and to stop by computer input within Series IX. This enables repeated cycling as desired for chewing simulation. The INSTRON is calibrated prior to load measurement. To do this, the appropriate load cell is attached to the INSTRON.
The load cell has to be chosen in accordance with the expected data ranges. Based on this, the kN load cell is chosen as appropriate for the data ranges of interest. The test sample is placed on the lower platen, and the upper platen is adjusted such that the upper platen is in contact with the sample but exerts no measurable force. A constant cross-head velocity of 50 mm/min is used and set on the controller panel for accurate control over the position of the upper platen during testing. The diameter of the test sample at the start of the measurement is set as the maximum extension on the controller panel. To effectively simulate chewing, the test sample is compressed down to 80% of its original average width. This is set as the minimum extension limit. The upper platen is then actuated.

This motion actuation also initiates the data procurement by Series IX
software on the personal computing device. Increasing compression translates into increasing force readout, with a peak attained at 80% compression. Following maximum conipression, the upper platen is cycled back by the controller at the same velocity to the initial position. A
flexible sample relaxes as is observed from the increasing force measured at the upper platen after stopping motion at the maximum extension. Each cycle is defined as one compression and a complete retraction stroke. The-samples are cycled through two cycles and a final compression stroke prior to allowing relaxation. Each bite causes additional flattening of the sample. At the end of the third compression stroke, the upper platen is stopped at the 80% compression limit. As the flexible sample relaxes and expands, it pushes against the upper platen which provides a force feedback to the load cell. The sample is then allowed to relax for 15 minutes or an appropriate time of data collection.
Depending on the extent of relaxation, different sanlples provide varying force response.
Without intending to be limited by theory, the more 'chewy' samples cause a more significant increase in the reversal of compression over this relaxation period. A curve of force versus time is generated from this data, resulting in a measurable plateau. The force, in kN, at the plateau is the Maximum Relaxation Force exhibited by the test sample. Figure 1 is illustrative of resulting curves and plateaus for three illustrative, inventive pet food compositions of the present invention.
This force acts on the horizontal cross-section of the sample. Knowing the sample dimensions (length = 1 inch and diameter) enables calculation of the horizontal cross sectional area and the Maximum Relaxation Stress generated within the sample per the Equation I that follows.
Equation I:
Maximum Relaxation Stress (MPa) = Force (kN) x 1000/Area (mm2) Figure 2 is illustrative of sample contrast brought out in terms of geometry-independent stress measurements i.e. Maximum Relaxation Stress, so as to be able to compare samples of different dimensions.
METHODS OF MAKING
The pet food compositions herein are made according to methods which will be well known by the ordinarily skilled artisan. To illustrate, the compositions of the present invention may be prepared by mixing or grinding all components singularly or in suitable combinations together, and in water where appropriate, agitating mechanically until all of the ingredients have been solubilized, dispersed, or otherwise mixed, as applicable.
Wherein certain processes such as extrusion (to form chews, for example) or baking are utilized, such processes will be well-known in the art.
It should be understood that every maximunl numerical limitation given throughout this specification includes every lower numerical limitation, as if such lower numerical limitations were expressly written herein. Every minimum numerical limitation given throughout this specification includes every higher numerical limitation, as if such higher numerical limitations were expressly written herein. Every numerical range given throughout this specification includes every narrower nunierical range that falls within such broader numerical range, as if such narrower numerical ranges were all expressly written herein.
All parts, ratios, and percentages herein, in the Specification, Examples, and Claims, are by weight and all numerical limits are used with the normal degree of accuracy afforded by the art, unless otherwise specified.

EXAMPLES
The following are non-limiting examples of the present pet food compositions which may optionally be prepared utilizing conventional methods. The following examples are provided to illustrate the invention and are not intended to limit the scope thereof in any manner.

Example 1 A chew product adapted for use by a domestic dog is prepared using the following components at the approximate indicated amounts:
Component Approximate Amount %
b wei ht of the com osition Wheat Flour and Wheat Gluten 53 High Fructose Corn S ru 13 Glycerin and Gl ce 1 Monostearate 12 Beet Pulp 4 Sodium Tri ol hos hate 2 Vegetable Oil 2 Sulfur 0.03 Minors 3 Water Quantum satis The chew product can be prepared in accordance with the methods generally described above. In particular, all dry components are weighed, mixed, and ground to the desired particulate size. The mixed and ground dry components are then mixed with the liquid components in a pre-conditioner of a single screw extruder. Steam is then added to the pre-conditioner in accordance with ordinary conditions. The resulting mixture is then extruded through -an appropriately set extruder screw. The extrudate is cut to a desired length using rotating knives or intermittent knives. The product is then cooled to room temperature and packaged in an air-impermeable container.

Example 2 A chew product adapted for use by a domestic dog is prepared using the following components at the approximate indicated amounts:
Component Approximate Amount b wei ht of the com osition Wheat Flour and Wheat Gluten 57 High Fructose Corn Syrup 13 Glycerin and Gl ce l Monostearate 13 Beet Pulp 1 Sodium Tri ol hos hate 2 Vegetable Oil 1.5 Minors 2.5 Sulfur 0.03 Water ua~2turn satis The chew product is generally prepared and packaged in accordance with the methods described at Example 1 herein.
All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention.
While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention.
It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.

Claims

1. A pet food composition having a Maximum Relaxation Stress of at least 2.5 MPa, preferably at least 2.8 MPa, more preferably at least 3 MPa.

2. A pet food composition having a Maximum Relaxation Force of at least 1 kN;
preferably at least 1.5 kN; more preferably at least 2 kN.

3. The pet food composition according to Claim 1 or Claim 2, which is a supplement; preferably wherein said supplement is a chew; preferably wherein said supplement is a treat.

4. The pet food composition according to any one of the preceding claims, further comprises water.

5. The pet food composition according to any one of the preceding claims, which comprises a humectant that is selected from the group consisting of polyhydric alcohols, sugars and mixtures thereof, preferably at least one humectant is corn syrup.

6. The pet food composition according to any one of the preceding claims, comprising a primary component, by weight of the composition, wherein the primary component is at least one grain source; wherein said grain source is selected from the group consisting of corn, oats, rice, milo, sorghum, barley, wheat, and mixtures thereof; preferably wherein at least one grain source is wheat.

7. A process for preparing a pet food composition, wherein said process comprises:
(a) mixing all components;
(b) agitating all components until mixed; and (c) extruding said pet food composition.