Γ00011 This application claims the benefit of priority of United States Provisional Patent Application Number 61/435,343, filed January 23, 2011, which is incorporated herein bv reference where allowed by applicable law/and or regulation.

Field of the Invention

Γ00021 The invention relates to pet food and similar compositions which are formed bv extrusion or baking . More specifically, the invention relates to extrusion-processed pet food compositions comprising kibble having high meat content and methods for producing such compositions.

Background of the Invention

Γ00031 Pets have become an integral part of the lives of people around the globe. While some pet owners cook food for their pets, the vast maiority purchase commerciallv-available pet foods, such as canned foods and kibble, to meet the nutritional needs of their pets. Global pet food sales in 2009 reached approximately 52 billion U.S. dollars, with much of those sales being attributed to dog and cat foods. Most commerciallv-available pet food comes in a drv form

(often known as "kibble" ^" ), a semi-moist form, or a wet (e.g., canned ^" ) form.

Extruded and baked treats and supplements also form a maior portion of the pet

l food market. Treats and supplements may be extruded, baked, or formed under pressure, freeze dried, or frozen and are generally formed of more expensive ingredients than are kibble products. Dry pet food generally contains 6-10 percent moisture by volume, as compared to 75-92 percent in canned food. Dry food is considered to be more nutritionally dense than canned food because it has lower moisture content. Pet food kibble accounts for more than 60 percent of all cat food and dog food sales in the United States, for example, and is packaged in paper, film, foil, boxes or laminated containers of these materials, ranging is sizes of a few ounces to larger bags weighing up to 50 pounds.

Γ00041 Kibble and the maiority of treats are either extruded or baked. Extrusion is a continuous cooking process, using water, high pressure steam and mechanical sheer under and up to several atmospheres of pressure. During the extrusion process, the raw material for the kibble consist of various sources of animal, plant, vegetable, organic and inorganic minerals, vitamins and purified amino acids, and mav be blended with raw meats. Nutritionally the kibble, whether extruded or baked, contains the six maior nutrient categories of protein, fat, fiber, carbohydrates, minerals and vitamins. Starches and fibers in the raw material are gelatinized during extrusion cooking, becoming more soluble and absorbing large guantities of water. Absorption of water bv the starch component promotes expansion of the product and binds the ingredients into a shaped palatable and nutritional matrix for easier feeding. The kibble, generally containing about 20-25 percent moisture at this point, is dried to a level of about 8 to 10 percent moisture. Once formed, kibble is often spraved and/or dried with vitamins, fats, oils, or anv other ingredients that may not be heat-tolerant, to complete both the nutritional and palatabilitv properties of the food .

Γ00051 Following a scientifically prepared recipe, the extrusion process consists of the raw materials first being ground to an appropriate particle size, which mav varv according to the cooking process and the ingredients. Ingredients forming a "dry mix" are passed through a pre-conditioner, where water, fats and oils mav be added. Steam is iniected at this point to start the cooking process. The pre-conditioned mix is then passed through an extruder, and forced through a die where it is cut to the desired length. The cooking process produces gelatinization of the starch as well as sterilization of the product.

Γ00061 The addition of fresh meat adds significant moisture and fat to the process, creating cooking and hydration problems in both the pre-conditioner and extruder. Recipes with levels of fresh meat in excess of 20 percent generally result in extruded kibbles that mav be very soft and easilv deformed, crushed or broken. If high levels of fibrous material are added to the recipe, it tends to disrupt the carbohydrate matrix of the product and qive a rouqh appearance to the product, as well as an excessive amount of fines. If the levels of starch are too hiqh, thev create problems with the extrusion process, produce increased levels of fines, and result in siqnificant levels of kibble breakaqe. Therefore, selection of inqredients for dry extruded food products requires careful analysis. One approach that has been taken to increase the amount of meat that may be incorporated into kibble has been described in United States Patent Number 6,410,079 (Cheuk, ei ^" al.). Cheuk ei ^" al. disclose a method for increasinq the meat content of drv pet food (i.e., kibble ^" ) by the addition of an amount of cellulosic material effective to allow extrusion and cuttinq of the resultinq product. While this disclosure provided an improvement in the pet food industry, the addition of cellulose to increase the meat content of drv food, often desirable in certain formulations such as those for weiqht loss and qlucose manaqement, is not qenerallv desirable because cellulose is siqnificantly less diqestible, providinq only a neqliqible contribution to the enerqv available from the food. Cellulose is fairly similar to starch on a qross enerqy basis, but the metabolizable enerqv is almost zero. Sufficiently hiqh levels of cellulose in a pet's diet mav also neqativelv affect the diqestibility of other nutrients, such as protein and minerals. Furthermore, addinq cellulose to the diet qenerallv increases fecal volume. Γ00071 Meat provides a full amino acid profile to the animal consuming it, and pet owners generally want to incorporate more meat into their pets' diets to improve both the nutrition and palatabilitv of the food . Kibble, however, provides a more convenient, longer shelf-life product that is more nutrient-dense because of its lower percentage of water. It would therefore be beneficial to provide higher levels of meat in a drv pet food product than those levels that are achievable in commercial products todav. It would be even more desirable to develop a method for incorporating more meat into a drv pet food product using one or more compositions that can add their own nutritional value to the food .

Summary of the Invention

Γ00081 The present invention relates to a composition comprising from about 30 percent to about 80 percent fine-milled flax seed and from about 20 percent to about 70 percent whev protein concentrate (WPO, bv weight. In various aspects, a composition of the invention mav comprise from about 55 to about 70 percent fine-milled flaxseed and from about 30 to about 45 percent WPC.

Γ00091 Aspects of the invention also relate to a pet food composition comprising from about 20 to about 90 percent bv weight of at least one meat product, and a flaxseed/WPC component, wherein the flaxseed/WPC component comprises from about 30 percent to about 80 percent fine-milled flax seed and from about 20 percent to about 70 percent WPC, bv weiqht of the flaxseed/WPC component, and the flaxseed/WPC component is present in an amount of from about 1.5 percent to about 18.5 percent bv weiqht of the meat. In certain aspects, such a pet food composition may comprise a flaxseed/WPC component comprisinq from about 55 to about 70 percent fine-milled flax seed and from about 30 to about 45 percent WPC, bv weiqht of the flaxseed/WPC component.

Γ00101 The invention also relates to a method for increasinq the meat content of an extruded food composition, the method comprisinq admixinq the meat and a flaxseed/WPC component to form a meat/flaxseed/WPC mixture, the flaxseed/WPC component comprisinq from about 30 percent to about 80 percent fine-milled flaxseed and from about 20 percent to about 70 percent WPC, bv weiqht of the flaxseed/WPC component, and the flaxseed/WPC component beinq added at from about 1.5 percent to about 18.5 percent bv weiqht of the meat; holdinq the mixture for from about 3 to about 30 minutes at from about 35 to about 60 deqrees Celsius, and processinq the mixture bv extrusion cookinq.

Γ00111 In some aspects of the invention, the flaxseed/WPC component is admixed with the meat and held at from about 45 to about 55 deqrees Celsius, and in some aspects, the holdinq time is from about 10 minutes to about 30 minutes. In some aspects, the extruded food composition is an extruded pet food composition.

Brief Description of the Drawings

Γ00121 Fiq. 1 is a bar graph illustrating the stool grade (shown on the X axis ^" ) distribution for animals consuming a higher-meat product of the invention. A grade of 4 is considered maximal and desirable, representing a stool that is of reasonable firmness. The number of observations is indicated on the Y axis.

Γ00131 Fig. 2 is a bar graph illustrating the ratio of selection freguencv of a leading, premium extruded drv food (Eukanuba ^® , Procter and Gamble, Cincinnati, Ohio ^" ) as compared to that of the composition of the invention.

"Premium" designates results for the Eukanuba ^® product and "Glanbia" designates results for the composition of the invention. Side-bv-side selection studies were performed, with results expressed as the ratio of freguencv of selection of one product over the other when animals were given a choice between the two products. Results for dog foods are shown in the top graph. Results for cats are shown in the bottom graph. As illustrated bv these results, the product of the invention has improved palatabilitv.

Γ00141 Fig. 3a is a graph representing the low, average, and high values of the amount of force applied to kibble to test for breakage. Fig. 3b is a graph representing the percentage of fines produced in a series of tests. It should be noted that the maximum percentage shown on the graph is still less than one percent.

Detailed Description

Γ00151 The inventors have discovered that the combination of two nutritionallv-valuable components— whev protein concentrate and flaxseed— can be used as functional ingredients to increase the amount of meat that mav be incorporated into a dry food composition, especially an extruded drv pet food composition. By mixing the flaxseed/whev protein concentrate composition with meat, it is possible to make the meat easier to process, providing a product with higher meat content and improved properties for an extruded food product, such as an extruded pet food product.

Γ00161 As used herein, a "meat" or "meat product" is raw, partially cooked, or cooked flesh including, but not limited to, beef, pork, chicken, turkev, fish, etc. Generally, raw meat is commonlv used in the preparation of many products such as pet food compositions produced bv extrusion cooking. "Flaxseed" is generally a fine-milled flaxseed, and mav preferably be a full-fat fine-milled flaxseed. Γ00171 Formed pet food compositions may be produced by bakinq or by extrusion cookinq. The extrusion method qenerally subiects the food

components to hiqh pressure and temperature, qelatinizinq the starch that may form a component of the food inqredients. Hiqh levels of starch, however, cause problems in the extrusion process and produce a product that is hiqher in pieces broken into very small pieces, known in the industry as "fines." Hiqh levels of meat in an extruded drv product qenerally produce a denser product with a lower percentaqe of cook, or qelatinization, resultinq kibble that is softer, less crunchv, and more deformable.

Γ00181 The inventors have developed a composition that facilitates incorporation of qreater quantities of meat into extruded and baked dry food products. The composition also provides siqnificant added benefits, such as the addition of beneficial nutrients such as branched-chain amino acids, omeqa-3 (alpha-linoleic ^" ) and omeqa-6 (linoleic ^" ) fatty acids, and qamma-tocopherols to the food products. Animals fed compositions of the invention demonstrated a siqnificant preference for the food product, indicatinq that it is of qreater

palatability to the animals. The effect appeared to be more pronounced in doqs than in cats, but was seen in both species. Feedinq compositions of the invention to doqs or cats resulted in stools of desirable firmness. Furthermore, compositions of the invention also demonstrated a kibble strength and texture that would generally be considered bv those of skill in the art in the pet food industry to provide a dental benefit to the animal consuming the composition. Also, processing compositions of the invention reguires less motor load on the extrusion eguipment and mav increase the processing time and efficiency.

Γ00191 Adding cellulosic material to an extruded pet food composition in order to increase the meat content has been previously described . However, high levels of fibrous ingredients mav disrupt the continuity of the product's carbohydrate matrix, resulting in the production of a kibble product that is rougher in appearance, easier to break, and produces excessive fines. The inventors therefore hoped to find an ingredient, or combination of ingredients that might solve that problem and produce a kibble product having higher meat content, while maintaining the desirable kibble characteristics of moisture level, percentage of cook, and kibble durability. What thev have produced is a product that meets these needs, but additionally provides a more palatable product that provides additional nutritional benefits to the animal. Furthermore, fresh meat typicallv has a range of from 68 percent to 78 percent moisture content, sometimes within the supply used in one production run. Adding the inventive composition improves fresh meat consistency and controls viscosity. Γ00201 The inventors developed a composition comprising from about 30 percent to about 80 percent fine-milled flax seed and from about 20 percent to about 70 percent whev protein concentrate (WPC ^" ), bv weiqht, which, when admixed with meat, can be used to increase the amount of meat that can be incorporated into an extruded food product, such as an extruded pet food product. In various aspects, the composition mav comprise from about 55 to about 70 percent fine-milled flaxseed and from about 30 to about 45 percent WPC.

Γ00211 The inventors have demonstrated that thev can use the flaxseed/WPC composition to produce a pet food composition comprising from about 20 to about 90 percent bv weiqht of at least one meat product, and a flaxseed/WPC component, wherein the flaxseed/WPC component comprises from about 30 percent to about 80 percent fine-milled flax seed and from about 20 percent to about 70 percent WPC, bv weiqht of the flaxseed/WPC component, and the flaxseed/WPC component is present in an amount of from about 1.5 percent to about 18.5 percent bv weiqht of the meat. In certain aspects, such a pet food composition mav comprise a flaxseed/WPC component comprisinq from about 55 to about 70 percent fine-milled flax seed and from about 30 to about 45 percent WPC, bv weiqht of the flaxseed/WPC component. Γ00221 The inventors have also developed a method for using the flaxseed/WPC composition to increase the meat content of an extruded food composition, the method comprising admixing the meat and a flaxseed/WPC component to form a meat/flaxseed/WPC mixture, the flaxseed/WPC component comprising from about 30 percent to about 80 percent fine-milled flaxseed and from about 20 percent to about 70 percent WPC, bv weight of the flaxseed/WPC component, and the flaxseed/WPC component being added at from about 1.5 percent to about 18.5 percent bv weight of the meat; holding the mixture for from about 3 to about 30 minutes at from about 35 to about 60 degrees Celsius, and processing the mixture bv extrusion cooking.

Γ00231 In some aspects of the invention, the flaxseed/WPC component is admixed with the meat and held at from about 45 to about 55 degrees Celsius, and in some aspects, the holding time is from about 10 minutes to about 30 minutes. In some aspects, the extruded food composition is an extruded pet food composition.

Γ00241 Heating a slurrv, formed of the admixed ingredients, prior to extrusion, provides an added benefit in that it appears to decrease the drv density of the finished product (a desirable outcome, since more dense kibble tends to be more difficult to form into the desired shapes, easier to break into fines, etc.) and to increase the cook percentage. In Table 1, Run #101206-09 was performed without heatinq prior to addinq the mix to the extruder and Run #101207-10 was performed bv heatinq the mix to 50 deqrees Celsius prior to addinq it to the extruder.

Table 1

Γ00251 Sources of whev protein include, for example, commerciallv- available whev protein concentrate, (Glanbia Nutritionals, Monroe, Wisconsin ^" ), which is made from fresh whev usinq ultrafiltration, then sprav-dried to produce a product comprisinq about 78-80 percent protein. Sources of flaxseed mav include, for example, full-fat milled flaxseed (Glanbia Nutritionals company, Monroe, Wisconsin ^" ) , which provides flaxseed from Linum usitatissimum. Flaxseed has proven to be particularly effective for use in the inventive compositions and methods described bv the inventors. Meat products mav include anv suitable meat for pet food kibble, including, but not limited to, mechanically deboned chicken (MDC ^" ), beef, turkey, buffalo, fish, and lamb.

Γ00261 Extrusion cooking processes for pet food are known to those of skill in the art. Extruders, such as those produced by Wenger ^® (Sabetha, Kansas ^" ) are commercially available, as are multiple publications related to conditions for their use. Briefly, by wav of a non-limiting example, desired ingredients are generally ground to a particle size that is suitable for the product and its processing conditions. Drv ingredients may be mixed together as a first step, to form a drv mix, or dry ingredients mav be processed through a grinder which deposits the ground material into a mixer. In the mixer, dry ingredients are mixed to an even consistency and particle distribution. Pre-conditioning involves the addition of heat and steam to the mix, and the pre-conditioned mix is then fed into either a single- screw or double-screw extruder, where the process of pushing the product through the confined space of the extruder increases the heat and pressure applied to the product. This heat and pressure produce gelatinization of cellulosic/starch

(carbohydrates ^" ) components in the product. Extruded product is cut into desired shapes and dried in a drying oven, then cooled . Product (kibble ^" ) mav then be coated with various desired coatings, such as fats/oils (often containing fat-soluble vitamins and other ingredients ^" ), probiotic microorganisms, etc. The coating process may be performed in a rotating drum, which produces force on the kibble sufficient to break it when high levels of starch, cellulose, and/or meat protein are present.

Γ00271 Additional breakage may occur as the result of packaging, packing for transportation, and shipping of product. The inventors have

discovered, however, that the use an ingredient combination of flaxseed and whev protein, with the optional addition of milk mineral, produces a kibble product that is resistant to significant breakage and produces low levels (less than 1 percent ^" ) of fines, while being highlv palatable to the dog and/or cat and providing increased nutritional value. The ingredient composition of the invention, comprising flaxseed and whev protein concentrate, binds with ground fresh meat, reduces its stickiness, and increases its ability to flow through the extruder. This results in a motor load reduction in the extruder, as shown in Table 2.

Table 2

As shown in Table 2, at about 1.8 percent bv weiqht of the formula, OptiSol 9000 (which contains the inventive composition comprising whev protein concentrate and flaxseed ^" ), reduces motor load bv approximatelv ten percent and increases the RPM rate of the extruder bv approximatelv 8-9 percent over the control without OptiSol 9000 (which should decrease production time and extend the life of the extruder motor ^" ). Γ00281 It should be understood bv those of skill in the art that a variety of additional ingredients mav be added to a dry food product comprising meat, flax seed, and whey protein concentrate as described herein. Such ingredients mav include, for example, vitamins, minerals, amino acids, plant extracts, and flavorings. Ingredients suitable for pet food compositions are known those of skill in the art of animal nutrition and pet food processing.

Γ00291 The addition of flax seed and whev protein concentrate as described bv the inventors provides added nutritional benefits, in addition to providing a chemical/physical benefit in terms of facilitating the addition of higher meat levels. For example, about 28 percent of the weight of full-fat flax seeds is fiber, which is a beneficial level, but not a level that is likely to lead to increased stool volume. Animal feeding studies have demonstrated that compositions of the invention produce firm stools of a volume and color that is characteristic of good fermentation and nutrient absorption. Flaxseed also contains 8.5 to

39.5mg/100grams of gamma-tocopherols (gamma-tocopherol is a Vitamin E homolog that has multiple beneficial properties ^" ), as well as the omega-3 fattv acid alpha-linoleic acid and the omega-6 fatty acid linoleic acid. Flax is gluten-free and low in carbohydrates, as well. Whev protein supplies significant guantities of branched-chain amino acids and studies have shown that it has multiple desirable benefits in humans and animals, including promoting weight loss. Among the branched-chain amino acids provided bv whev is the amino acid leucine, which is present at higher levels in whev proteins than in most other forms of protein.

Leucine is beneficial for increased muscle synthesis and repair and provides a variety of other metabolic benefits, many of which have only recently been discovered.

Γ00301 The stronger individual kibbles produce bv the composition of the invention and the method of the invention are both more resistant to breakage bv the addition of external force and highlv palatable. It is well-known in the pet food industry that the farther an animal's tooth sinks into the kibble, the greater the dental benefit, as drv kibble produces enough of an abrasive effect on the tooth to decrease the amount of tartar that mav form there. Therefore, the dry food products produced using the ingredient composition of the invention and the method of the invention mav provide an additional dental benefit for animals consuming these products.

Γ00311 Extruded and dried kibble mav be subjected to significant force through the processes of coating, packaging, packing for transport, and storage of the product, which is most often packaged in bags of paper, foil, boxes, laminates or plastic. Compositions of the invention produce a product that withstands these forces sufficiently to produce levels of fines of less than about one percent, which may result in a cost savings due to the decreased need for physical measures to reduce breakage and decreased loss of product. Greater consumer satisfaction mav also result from the decrease in residue in the bottom of an individual pet food baq.

Γ00321 Pet owners are well aware that the consistencv and volume of an animal's feces are important to the owner in terms of convenience with which the feces mav be disposed of, the overall amount of feces produced by the animal, etc. Even more importantly to most owners, qood consistencv, color, and reasonable volume are indicators of a pet's overall health and qenerallv indicate that nutrients have been appropriately absorbed, the food promoting qood fermentation and absorption within the intestines of the animal. Products produced by incorporating compositions of the invention have demonstrated their

effectiveness at producing such desirable stool characteristics.

Γ00331 The invention mav be further described bv means of the following non-limiting examples. Examples

Γ00341 A dry mix was made, using 30.07 percent chicken meal, 2.1 percent catfish meal, 2.8 percent egg, 26.97 percent corn, 26.97 percent brown rice, 6.79 percent beet pulp, 2 percent yeast, 0.5 percent potassium chloride, 0.5 percent salt, 0.3 percent potassium sorbate, 0.45 percent vitamin premix, 0.1 percent TM 95, 0.1 percent choline chloride, 0.2 percent methionine, and 0.2 percent Ivsine by weight. This drv mix was used to produce a product comprising meat mix and dry mix, the various batches of meat mix comprising the ingredients listed in Table 3.

Table 3

Batch Number Meat Source/Amount OptiSol 9000* (Amount

(expressed as percent of expressed as percent of total drv mix) total drv mix)

1 MDC**/36.5 None

2 MDC/36.5 3.5

3 M DC/40 3.8

4 MDC/50 4.8

5 M DC/44.7 4.3

6 M DC/44.7 8.6

7 M DC/44.7 4.3

(OptiSol 9000 substituted with Pea Protein and Potato Starch ^" )

8 Buffalo/44.7 8.6

9 Lamb/44.7 8.6

10 MDC/50 8.6

11 Buffalo/52 8.6

12 M DC/44.7 8.6

* - Optisol 9000 composition : 61.59 percent flaxseed , 38.41 percent whev protein concentrate. MDC=mechanicallv deboned chicken.