GB1579324A - Intermediate moisture pet foods - Google Patents

Description

(54) IMPROVEMENT TO INTERMEDIATE MOISTURE PET FOODS (71) We, QUAKER OATS LIMITED, a British Company of P.O. Box No. 13, Bridge Road, Southall, Middlesex UB2 4AG, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a proteinaceous intermediate moisture food product, primarily intended for feeding to domestic pets and the production thereof.

Known intermediate moisture pet foods generally consist of meaty materials (including meat and meat-by-products), soya, cereal grains, starches, bacteriostatic and antimycotic agents and other additives and have moisture contents lying between those of canned and dry foods. Usually they possess moisture contents of between 15 and 45 percent by weight.

Such foods have the great advantage that they are stable after pasteurization and do not need drying, canning, freezing or irradiation. To achieve such stability they incorporate certain water soluble materials which exert bacteriostatic effects. Water soluble materials generally used, singly or in combination, are chosen from the group: sugars, corn syrups, polyhydric alcohols, mineral salts, organic and inorganic acids.

Such preservative materials reduce the water activity of the product to a value below that of pure water at the same temperature and when correctly used prevent bacterial spoilage of the food. (Water activity is defined as the ratio of the vapour pressure of water in the finished product to the vapour pressure of pure water at the same temperature). Often the products also contain antimycotics to inhibit mould and yeast growth.

The structure of intermediate moisture pet foods generally depends on their viscosity or on the presence of proteins or starches that confer some measure of solidity to the finished product. The addition of starch to retard melting and increase finished product rigidity has also been described (British Patent 1 217 662). If the moisture content of these products is below 30 percent these foods may lack high animal acceptance and be of less than optimum appearance when compared to similar products of higher moisture. Products of higher moisture are more difficult to produce due to their stickiness and as their moisture increases their structures become increasingly soft and unmanageable.This problem has hitherto been overcome by incorporating significant amounts of heat denaturable or theromplastic proteins capable of conferring a firm structure to the finished product (UK Patents 1 380 394 and 1143 373 and 1 217 662).

The present invention consists of an intermediate moisture proteinaceous pet food having a moisture content in the range 24-45% by weight, a pH in the range 4.0 to 7.0 and containing sufficient water soluble preservative material to render the product bacteriologically stable by reducing the water activity of the product, that additionally contains sodium alginate (or other alginic acid derivative), preferably in an amount from 0.3 to 3.0 percent by weight, crosslinked by a divalent or multivalent cation to produce a gelled structure. Thus, it has been surprisingly found that an alginate gel may be formed even in the presence of water soluble preservative material.

Of these products, that made and gelled in the 30-40% moisture range, e.g. with 1% sodium alginate and crosslinked by calcium ions is Preferred. Products in the pH range of 4.0- .0 are envisaged but a pH of 4.5-5.5 is preferred. Preferred solutes for water activity reduction are sucrose, sodium chloride, glycerine, propylene glycol and corn syrup, and a preferred range for water activity is from 0.75 to 0.91.

This invention also consists in a process for the production of a proteinaceous food product in which a mix is made comprising pasteurized or unpasteurized meaty or other edible proteinaceous material, moisture and water-soluble substances sufficient to render the product bacteriologically stable by reducing the water activity of the product, sodium alginate (or other alginic acid derivative); the resultant mix is heated to effect pasteurization; the resultant mix is gelled by the incorporation of a divalent or multivalent cation into the ingredient mix, before during or after such pasteurization.

A preferred embodiment comprises a method of manufacturing an intermediate moisture food having a moisture content of between 24 and 45% (preferably 30-40 percent) by weight, wherein sodium alginate or other alginic acid derivative, e.g. in an amount from 0.3 to 3.0% by weight, is incorporated and caused or allowed to form a gel by cross-linking with divalent or multivalent cations and so conferring structure to the product.

Preferably, the gel is formed slowly to facilitate handling, texturing and shaping of the product. As gelling is chemically controlled (for example by releasing calcium crosslinking ions in a sodium-alginatecontaining substrate) some means of controlling the rate of release of crosslinking cations is required. This can be achieved by the initial or gradual addition of a sparingly soluble source of calcium such as a calcium salt, which goes slowly into solution in a generally acid medium to provide controlled crosslinking. Such a crosslinking agent can be added before, during and after pasteurization. It is also possible, by the addition of a slowly soluble acid to release calcium crosslinking ions from an otherwise insoluble calcium salt.

In the preferred form of the invention an ingredient mix containing meaty materials, other edible proteinaceous matter, moisture, sufficient water soluble materials to reduce the water activity of the finished product to the desired level and other additives as desired is prepared. The mix additionally contains a source of calcium ions and sodium alginate (or other suitable derivative of alginic acid) and is then pasteurized. After pasteurization a slurry of a slowly soluble acid (for example fumaric acid in aqueous suspension) is added and the mass is rolled, extruded and/or cut. The shaped pieces set to a firm heat irreversible gel structure and the speed of gel formation can be controlled by temperature and pH; cooling and increased acidity accelerate gel formation.

EXAMPLE The following is an example of the production of a food product according to the invention.

Ingredients % by weight 1. Sucrose 18.000 2. Soya Flour 10.000 3. Wheat Flour 9.700 4. Meat and Bone Meal 15.000 5. Di-calcium phosphate 1.000 6. Sodium Alginate 1.000 7. Potassium Sorbate 0.100 8. Vitamin and Mineral Mix 1.000 9. Propylene Glycol 4.000 10. Tripe (ground through 3 mm plate) 11.700 11. Beef Fat 4.000 12. Water 4.000 13. FumaricAcid 1.500 14. Salt 1.000 15. Colouring 0.024 16. Water 17.976 100.000 (a) Ingredients 1 to 8 were mixed to form a premix.

(b) To this premix, ingredients 9-12 were added and the resultant mass mixed for 5 minutes to form a homogenous mixture.

(c) Ingredients 13-16 were mixed at ambient temperature to give a solution of salt and colour containing a suspension of partially dissolved acid. The suspension was continually stirred to form a homogenous suspension.

(d) The mass from step (b) was heated by indirect steam to 850C-900C for 2 to 3 minutes and then cooled by indirect water to 60-70"C.

(e) The partially cooled mass was then mixed with the homogenous suspension from step (c) in a high speed mixer immediately prior to shaping or cutting the resultant mixture into pieces or strands. The whole step (e) was completed in under 10 seconds to minimise initial gel breakdown by mechanical action.

(f) The resultant pieces or strands were cooled to ambient temperature and subsequently packed in heat sealed plastic sachets of low water vapour transmission. A moisture content of 34% and a water activity of 0.88 were recorded on the final product.

Such shaped and gelled products were judged to be attractive and meat like in appearance and found to have high animal acceptance.

WHAT WE CLAIM IS: 1. A proteinaceous food product, primarily intended as a food for domestic pets, containing meat and/or meat by products and/or other edible proteinaceous material with a moisture content in the range 24-45% by weight, a pH in the range 4.0 to 7.0 and containing sufficient water

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. activity is from 0.75 to 0.91. This invention also consists in a process for the production of a proteinaceous food product in which a mix is made comprising pasteurized or unpasteurized meaty or other edible proteinaceous material, moisture and water-soluble substances sufficient to render the product bacteriologically stable by reducing the water activity of the product, sodium alginate (or other alginic acid derivative); the resultant mix is heated to effect pasteurization; the resultant mix is gelled by the incorporation of a divalent or multivalent cation into the ingredient mix, before during or after such pasteurization. A preferred embodiment comprises a method of manufacturing an intermediate moisture food having a moisture content of between 24 and 45% (preferably 30-40 percent) by weight, wherein sodium alginate or other alginic acid derivative, e.g. in an amount from 0.3 to 3.0% by weight, is incorporated and caused or allowed to form a gel by cross-linking with divalent or multivalent cations and so conferring structure to the product. Preferably, the gel is formed slowly to facilitate handling, texturing and shaping of the product. As gelling is chemically controlled (for example by releasing calcium crosslinking ions in a sodium-alginatecontaining substrate) some means of controlling the rate of release of crosslinking cations is required. This can be achieved by the initial or gradual addition of a sparingly soluble source of calcium such as a calcium salt, which goes slowly into solution in a generally acid medium to provide controlled crosslinking. Such a crosslinking agent can be added before, during and after pasteurization. It is also possible, by the addition of a slowly soluble acid to release calcium crosslinking ions from an otherwise insoluble calcium salt. In the preferred form of the invention an ingredient mix containing meaty materials, other edible proteinaceous matter, moisture, sufficient water soluble materials to reduce the water activity of the finished product to the desired level and other additives as desired is prepared. The mix additionally contains a source of calcium ions and sodium alginate (or other suitable derivative of alginic acid) and is then pasteurized. After pasteurization a slurry of a slowly soluble acid (for example fumaric acid in aqueous suspension) is added and the mass is rolled, extruded and/or cut. The shaped pieces set to a firm heat irreversible gel structure and the speed of gel formation can be controlled by temperature and pH; cooling and increased acidity accelerate gel formation. EXAMPLE The following is an example of the production of a food product according to the invention. Ingredients % by weight 1. Sucrose 18.000 2. Soya Flour 10.000 3. Wheat Flour 9.700 4. Meat and Bone Meal 15.000 5. Di-calcium phosphate 1.000 6. Sodium Alginate 1.000 7. Potassium Sorbate 0.100 8. Vitamin and Mineral Mix 1.000 9. Propylene Glycol 4.000 10. Tripe (ground through 3 mm plate) 11.700 11. Beef Fat 4.000 12. Water 4.000 13. FumaricAcid 1.500 14. Salt 1.000 15. Colouring 0.024 16. Water 17.976 100.000 (a) Ingredients 1 to 8 were mixed to form a premix. (b) To this premix, ingredients 9-12 were added and the resultant mass mixed for 5 minutes to form a homogenous mixture. (c) Ingredients 13-16 were mixed at ambient temperature to give a solution of salt and colour containing a suspension of partially dissolved acid. The suspension was continually stirred to form a homogenous suspension. (d) The mass from step (b) was heated by indirect steam to 850C-900C for 2 to 3 minutes and then cooled by indirect water to 60-70"C. (e) The partially cooled mass was then mixed with the homogenous suspension from step (c) in a high speed mixer immediately prior to shaping or cutting the resultant mixture into pieces or strands. The whole step (e) was completed in under 10 seconds to minimise initial gel breakdown by mechanical action. (f) The resultant pieces or strands were cooled to ambient temperature and subsequently packed in heat sealed plastic sachets of low water vapour transmission. A moisture content of 34% and a water activity of 0.88 were recorded on the final product. Such shaped and gelled products were judged to be attractive and meat like in appearance and found to have high animal acceptance. WHAT WE CLAIM IS:

1. A proteinaceous food product, primarily intended as a food for domestic pets, containing meat and/or meat by products and/or other edible proteinaceous material with a moisture content in the range 24-45% by weight, a pH in the range 4.0 to 7.0 and containing sufficient water

soluble preservative material to render the product bacteriologically stable by reducing the water activity of the product, that additionally contains sodium alginate (or other alginic acid derivative) crosslinked by a divalent or multivalent cation to give a gelled structure.

2. A food product as claimed in claim 1 in which the divalent cation is calcium.

3. A food product according to claim 1 or 2 where the sodium alginate (or other alginic acid derivative) is present at a level of between 0.3 and 3.0 percent by weight.

4. A food product according to claim 1, 2 or 3 having a water activity in the range of 0.75 to 0.91.

5. A food product according to any of claims 1 to 4 with a pH in the range 4.5 to 5.5.

6. A food product according to any one preceding claim with a moisture content in the ran 30 to 40%.

7. food product according to any of claims 1 to 6 in the form of cut or shaped pieces.

8. A food product substantially as described in the example given herein.

9. A process for the production of a proteinaceous food product in which a mix is made comprising pasteurized or unpasteurized meaty or other edible proteinaceous material, moisture and water-soluble substances sufficient to render the product bacteriogically stable by reducing the water activity of the product, sodium alginate (or other alginic acid derivative); the resultant mix is heated to effect pasteurization; the resultant mix is gelled by the incorporation of a divalent or multivalent cation into the ingredient mix, before during or after such pasteurization.

10. A process as claimed in claim 9 in which the source of calcium is sparingly soluble to give slow formation of the gel.

11. A process according to claim 8 in which there is incorporated in the mix an insoluble source of calcium or other suitable divalent or multivalent cations, and in which cations are liberated from this by the addition of an organic or inorganic acid.