GB1583644A - Pet food - Google Patents

Description

(54) IMPROVEMENTS IN AND RELATING TO PET FOOD (71) We, SPILLERS LIMITED, a British Company, of Old Change House, 4-6 Cannon Street, London EC4M 6XB, 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 present invention concerns improvements in and relating to pet food. It relates particularly to a product which is acceptable to domestic pets and which contains textured vegetable protein and flavourous enzymatically digested meat, meat offals or meat by-products.

Hitherto, products which have a moisture content between that of canned pet foods and dry pet foods known within the art as "intermediate moisture foods" which lie in the moisture content range of 15 - 50 per cent by weight of final product. have suffered in acceptability both to pet and owner in their lack of texture resembling meat.

Within the art, it is well known that when producing products having intermediate moisture contents. to achieve bacteriological stability whilst maintaining the soft and moist characteristics of the product, one has to employ specific levels of sugars. plasticisers such as polyhydric alcohols. antimycotics, food acids and salts in amounts sufficient to stabilise the foodstuff but without being detrimental to the nutritional requirements and acceptability to the pet. It is further known in the art that when producing expanded textured vegetable proteins. the presence of such sugars, plasticisers. antimycotics. acids and salts in sufficient quantities to stabilise an intermediate moisture food, impedes, if not completely prevents. the texturisation of the vegetable protein into a texture analogous to that of meat.Furthermore. it is known to those skilled in the art of producing pet foods that textured vegetable proteins. as exemplified by textured soya protein, are not very palatable to pets.

It is further known within the art that enzymatically digested meat, meat offals or meat by-products are particularly palatable to pets. Until now the use of such digested products has been restricted to use in dry pet foods as coatings or as an integral part of the pet food grist before being baked or extruder cooked.

The present invention provides a meat-like textured vegetable protein, having a moisture content of 15^/ to Suck bv weight of final product. rendered palatable to pets and stable to microbiological spoilage by infusing textured vegetable protein as hereinafter defined with a solution of enzymatically digested meat, digested meat offals or digested meat by-products as hereinafter defined and with a preserving solution.

Bv infusing the textured vegetable protein with the preserving solution and the enzymaticallv digested meat. meat offal. or meat by-products rather than attempting to include them before the expansion and texturising stage. the best obtainable neat-like texture is maintained.

The preserving solution should contain all the necessary ingredients e.g. sugars.

polyhydric alcohols. antim!cotics. acids and salts to provide microbiological stability.

There should be sufficient of the enzymatically digested melt meat offal or meat by-products to make the meat-like textured vegetable protein acceptable to pets.

The term ''textured vegetable protein" as used herein refers to products manufactured bv mixing protein and water to form a dough. thereafter feeding the mixed dough-like material into an extruder-cooker where it is subjected to heat. pressure and mechanical work and subsequently extruding the mixture through an orifice into the atmosphere where it expands to form what has been characterised as a meat-like, plexilamellar, fibrous structure.

The term "sugars" means water soluble monosaccharides, the reducing and non-reducing polysaccharides and their degradation products. Conveniently the amount of sugar is below 15% by weight.

By the term "polyhydric alcohol" we mean propylene glycol and 1,3 butanediol and edible alcohols having two or more hydroxyl groups conforming to the general formula HO CH2 (CHOH)n CH2OH where n = 0 - 6 Of most particular importance to this invention are the polyhydric alcohols glycerol, sorbitol, mannitol, propylene glycol and 1,3-butanediol. Conveniently the amount of polyhydric alcohol is below 4% by weight.

The term "antimycotic" refers not only to sorbic acid or its salts but also to the acids or salts of propionic, benzoic, crotonic or acetic acid and the parabans which are known to have an inhibiting or lethal effect on the growth of moulds and yeasts.

Salts which may be used as part of the preservation system are all the edible mono-, di- or tri-valent salts of organic or inorganic acids typified by such salts as sodium chloride, sodium citrate and calcium chloride.

The term "meat" refers to the flesh of cattle, sheep, swine, goats or other mammals, poultry or fish as so defined in the definition of feed ingredients published by the Association of American Feed Control Officials Inc.

The term "meat by-products" means all those materials so defined by this term in the definition of feed ingredients published by the Association of American Feed Control Officials Inc.

The term "enzymatically digested" in this context refers to digestion by the addition of a proteolytic enzyme, for example papain, bromalin, ficin or other proteolytic enzyme derived from plant, fungal, bacterial or animal gland sources or by the addition of such bacterial or fungal cultures themselves or by the addition of proteolytic enzyme-containing animal glands themselves or as admixtures with any one or more of the aforementioned enzymes or enzyme sources. Generally the process requirements for enzymatic digestion involve fine comminution of the meat. meat offals or meat by-products and adjustment of the pH to that most suited for the enzyme or enzyme source employed in the digestion, by the use of acid. alkali or buffer solutions. The pH range is suitably 4.5 - 10 but is preferably 6 - 8.Following comminution and pH adjustment, the digest is adjusted to a temperature most suitable for the action of the employed enzyme system within a temperature range of 15"C. to 55CC. but preferably within the range 35"C. to 45 C. The enzyme or enzyme source or mixtures thereof is now added to the comminuted, pH and temperature controlled meat, meat offals or meat by-products at a level depending on the proteolytic activity of the enzyme or enzvme source employed. Generally, the level is 1(-)t),()00-1t),0()0,0()0 units of enzyme as defined in the Food Chemicals Codex. per kilogramme of material to be digested.The digestion is continued with agitation for 5 minutes to 6 hours or longer until such time as the meat material is sufficiently digested. The digest is now acidified to pH 3 with orthophosphoric acid or other food acid and then heated to 70"C. - 1()() C. and held at this temperature for 2U minutes to inactivate residual enzyme and provide a degree of bacteriological sterilisation. The digested material, now a homogeneous liquid, is allowed to cool in drums and is stable for at least 6 months.

The term i ood acid is understood to include such acids as phosphoric, tartaric, citric, fumaric, hydrochloric or other edible food grade acids, which on addition to the produce cause reduction in the pH.

The product of this invention may have a density of below ().25 ounces per cubic inch and may, if desired. be coated with a preserved gel which improves the visual appearance of the product significantly The preserved gel coating material may be made. for example, by dissolving gelatin or other gelling material in hot water containing glycerol or other polyhydric alcohol and potassium sorbate or other antimycotic: : A typical gel coating would be Gelalin 20Ci; Gl!cero1 456/, Potassium sorbate ().25ck Wate r A. 75 C The constituents may be mixed without entrapping an excessive amount of air and held at 45 - 9()sC. before beiig sprayed on to the textured protein on a moving continuous belt to give an addition of about 10%. The coated protein is then allowed to cool in air at normal room temperature for up to 30 minutes and may then be aerobically packed in a container to maintain the moisture of the product.

The invention is illustrated by the following Examples which are preceded by three Preparations - the first being concerned with the preparation of a liver digest, the second with a chicken offal digest and the third with that of a preserving infusion liquor.

Preparation 1 A liver digest was prepared in the following way: 2kg of ox liver was finely comminuted through a 3mm mincer plate. A buffer solution to provide pH 6.7 was prepared by mixing 48.9g of potassium dihydrogen orthophosphate with 76.6g of di-potassium hydrogen orthophosphate and diluting to 1 litre with water. This litre of buffer solution was then added to the liver with 2g of papain proteolytic enzyme preparation (activity 30,000 units/mg). The temperature of the mix was adjusted to 38"C. and held at this temperature with gentle agitation for 4 hours. The now digested liver slurry was then adjusted to pH 3 by the addition of orthophosphoric acid, heated to 950C. for 30 minutes and then allowed to cool. The resulting product was now a homogeneous, stable, flowable liquid.

Preparation 2 A chicken offal digest was prepared in the following way: 2kg of mixed chicken offal and 500g of ox pancreas were comminuted through a 3mm mincer plate. ig of papain solution was added to 1 litre of water and added to the minced offals. The temperature was adjusted to 40"C and held at this with continuous agitation for 6 hours. The now digested chicken offal was then adjusted to pH 3.0 by addition of citric acid heated to 90"C. for 15 minutes and allowed to cool. The material was now a homogeneous flowable liquid.

Preparation 3 A preserving infusion was prepared from the following ingredients: Percentage by weight Water 30 Sucrose 27 Propylene Glycol 10 Hydrolysed Vegetable Protein - 4 (protein from any edible vegetable source which has undergone chemical hydrolysis by the effect of temperature and acid followed by neutralisation with alkali) Potassium Sorbate 0.25 Liver Digest (from Preparation 1) 14 Mineral Mix - 1.5 (a blend of the essential minerals required for the adequate nutrition of dogs or cats as defined by the National Research Council 1974) Vitamin Mix - 1.0 (a blend of the essential vitamins required for the adequate nutrition of dogs or cats as so designated by the National Research Council 1974) Animal Fat - 8.0 (the fat rendered from any of the species of animal included in the definition of "meat") Vegetable Oil - 2.5 (the oil in its crude or purified form which has been expressed, or extracted by solvents, from any edible vegetable source.) Emulsifier - 0.25 (any edible material capable of aiding the emulsification of oil or fat in water.) Sodium chloride 1.5 100.00 The water, propylene glycol, animal fat, vegetable oil, emulsifier and liver digest were mixed together and heated to 80"C. The dry materials were mixed together and added to the heated liquids with constant stirring.

This preserving infusion is now ready for use a material to add to rehydrate materials such as textured vegetable proteins to provide all the necessary vitamins, minerals, stabilisation and flavour enhancement for a complete diet for canines.

Example 1 Textured soya protein was prepared on a Wenger extrusion cooker, by plasticising a mixture of defatted soya flour with water and colouring material, extruding this plastic mixture through the Wenger extruder-cooker so that the material was subjected to sheer forces, heat and pressure before being extruded through an orifice into atmospheric pressure where the material expanded, forming a fibrous plexilamellar texture similar to meat. The extrudate was chopped by a rotating knife to form chunks of approximately half inch cubes.The textured chunks were allowed to cool and were found to have moisture content of 16 per cent by weight.

The textured soya protein chunks were put into a Z-blade configuration steam-jacketed mixer. The preserving infusion as produced in Preparation 3 was added to the textured soya protein in the mixer to the following formulation: Per cent by weight Textured soya protein (16% moisture) 45 Stabilising infusion (as per preparation 3) 55 100 The mix was slowly agitated and heated to 80 C. for 15 minutes until the preserving infusion was fully absorbed into the textured soya protein. The material was removed fro;n the mixer and allowed to cool to ambient temperature before being packed into suitable hermetically sealable containers. The material was now a meat-like textured product having intermediate moisture and was suitable for canine feeding.

Example 2 The textured product having intermediate moisture produced in Example 1 was coated with a preserved gel to impart a more succulent fresher appearance to the meaty lumps. The preserved gel was made to the following formula: Preserved gel Percentage by weight Gelatin powder 20 Glycerol 45 Potassium sorbate 0.25 Water 34.75 100.00 The water and glycerol were heated to 8() C. the potassium sorbate and gelatin were added with stirring until fully dissolved.After allowing about one hour's standing to ensure complete hydration of the gelatin. the preserved gel was coated on to the infused textured soya protein product made in Example 1 according to the following formulation: Percentage by weight Infused textured soya protein having intermediate moisture (from Example 1) 85 - C)O Prcserved gel 1() - 15 The preserved gel was coated on to the soft moist textured product by pouring the preserved gel onto the textured product having intermediate moisture in a revolving drum.

The gel coated product was allowed to set and cool to ambient temperature with gentle agitation to avoid adjacent lumps sticking together during gel setting.

The product now had a succulent glossy appearance of fresh meat lumps.

E.ral7ll)le 3 Textured soya protein was produced in the saine method is adopted in Example I except that following extrusion and cutting into half inch chunks, instead of cooling the product with resultant loss of moisture from about 25% to 16%, the hot textured soya protein lumps were fed into a steam-jacekted screw conveyor. The hot stabilising infusion as prepared in Preparation 3 was injected into the heated screw conveyor such that there was complete absorption of the infusion by the textured soya lumps by the time that the lumps reached the exit from the screw conveyor. The ratio of infusion to textured chunks was one to one in parts by weight.The now hot stabilised textured protein lumps having intermediate moisture were cooled to ambient temperature before being packed into hermetically sealed containers. The product was now suitable for canine feeding.

Ex{E7?ple 4 The textured soft and moist canine food was made as in Example 3 except that following cooling of the final product the lumps were coated with preserved gel as in Example 2.

Example 5 A meat-like textured cat food having intermediate moisture was prepared as follows: Textured soya protein was prepared in the same way as in Example 1 except that following extrusion the chunks were chopped into quarter inch chunks.

A preserving infusion was made to the following formulation: Percent by weight Water 41.85 Glycerol 10.00 Dextrose 16.09 Vitamin mix (feline) (as defined above) 1.63 Minerlls 1.()t) Dried yeast solubles (The water-soluble extract 2.17 of yeast dried to powder form) Liver Digest (per preparation 1) 15.22 lodised salt 3.25 Animal fat (as defined above) 8.70 100.00 The preserving infusion was infused into the textured soya protein chunks as made above to the following formation:: Percentage bv weight 1/4 inch textured soa protein lumps 54 Preserving infusion 46 I ()() The infusion was carried out in a Z-blade mixer in the same way as in Example I. This resulted in a meat-like testured product having intermediate moisture suitable for feeding to cats.

Eroslple 6 The c;tt food as made in Example 5 was was coated the sime method and sime preserving gel formulation as in Example 2. The product now had a succulent glossy appearance of small fresh meat lumps.

Example 7 A meat-like textured food having intermediate moisture was produced continuously as in Example 3, except that following extrusion the chunks were chopped into quarter inch chunks and were continuously infused with the preserving infusion formulation of Example 5 into the screw conveyor at a ratio of six parts quarter inch chunks of textured soya protein at 24% moisture content to four parts of preserving infusion, The product was now suitable for feeding to cats.

Example 8 The meat-like textured cat food having intermediate moisture produced in Example 7 was coated with preserved gel as in Example 2.

Example 9 The following infusion liquor was prepared by mixing in a steam jacketed Z-blade configuration mixer, Parts by Weight Glycerol 4.0 Propylene Glycol 8.0 Sugar 14.5 Salt 1.5 Dicalcium Phosphate 1.5 Vitamin mix (canine) 0.45 Tallow 5.0 Liver digest 10.0 Citric acid 0.4 Potassium sorbate 0.2 water 29.45 TOTAL . 75.00 To 75 parts by weight of this infusion liquor at 850C 25 parts of textured soya isolated protein (90% protein, 10% moisture) were added and infused over 10 minutes with constant slow mixing. The resultant product was a meat-like textured soft chunky pet food of 40% moisture content and suitable for canine feeding.

Example 10 A preserving infusion was made to the following formulation: Parts by weight Glycerol 3.5 Digest* 10.0 Corn syrup 8.0 Salt 2.1 Mineral mix 1.0 Vitamin mix (feline) 0.5 Fat 15.0 Yeast solubles 2.0 Water 9.0 51.1 parts by weight of the above infusion mixture, as prepared in preparation 3, were then infused into 48.9 parts of textured vegetable protein concentrate (70% protein, 8% moisturc) chunks of 1/4 inch. The product was chewy, meat-like and textured with a final moisture content of 20chic, suitable for feline feeding.

As prepared in Preparation 1.

Example 11 The following three dog foods were prepared: A B C Sugar 14.0 g Glycerol 4.0 ) Propylene Glycol 5.0 g Tallow 5.0 g same ) same Salt 1.0 ) ) Dicalcium phosphate 1.5 t Vitamin mix 0.45 ) Citric acid 0.27 ) Potassium sorbate 0.2 t Water 18.58 ) ) * Liver digest 10.00 ** Acidified cooked liver sltlrry - 10.00 Textured soya protein (1/2 inch chunks) 40 40 40 1.5% phosphoric acid 10.00 solution * As per Preparation 1.

** 2kg ox liver was minced through Smm plate. 935ml of water was added and 45g of orthophoshoric acid. The slurry was heated to 900C for 15 mins. and allowed to cool.

The three products were made by heating all the ingredients with the exception of the TSP in a Z-blade stream jacketed mixer to 90"C. The TSP was then introduced to the mixer and infused by slow mixing for 10 minutes. The products were allowed to cool. All 3 products were glazed as in Preparation 3 such that there were one part glaze to nine parts chunk.

The products were tested for palatability on panels of dogs, 26 dogs to each panel.

Product A was found to be very acceptable to the dogs. Products B and C were found to have low palatability with several dogs rejecting the product.

This Example shows that to achieve high palatability it is necessary to use digested offal, The use of undigested liver slurry did not sufficiently help the level of palatability of the product.

Example 12 100kg of infusion mixture was prepared to the following composition: Sugar 23.3 Glycerol 6.6 Propylene glycol 8.4 Tallow 8.3 Salt 1.7 Liver Digest 16.7 Dicalcium phosphate 2.5 Vitamin mix 0.8 Citric Acid 0.4 Potassium sorbate 0.3 Water 31.0 100.0 This infusion mixture was heated to 800C in a Z-blade, steam jacketed mixer and divided into two equal batches of identical composition. The first batch was infused into textured soya protein chunks of 16% moisture content and inch particle size at a ratio of 6 parts infusion liquor to 4 parts textured soya protein. The infusion took place in a Z-blade mixer over 10 minutes with slow mixing. The infused lumps were allowed to cool on trays.

The moisture of the product at 80"C was 33.4%. When cooled to ambient temperature the moisture was reduced to 28.5%, the product had good texture with a meat-like structure.

The remaining batch of infusion liquor was pumped into an extruder expander which was in the process of manufacturing textured soya protein chunks. The feed rate of infusion liquor to the expander was selected to achieve a composition of product issuing from the die plate of the extruder identical with that obtained by the post extruder infusion process. To achieve this extra water was added to the mix to allow for any moisture loss caused by flash off as steam. The composition through the expander was thus 7 parts defatted soya flour, 2 parts water, 11 parts infusion liquor. The material through the expander had a moisture content of 37.5%. This lost 4% moisture as steam flash off and a further 5% moisture on cooling. The final material had a moisture content of 28.5%.

It was apparent as soon as the infusion liquor was introduced to the expander that the plexilamellar meat-like texture of the protein was lost. Very dense, soft, untextured non-expanded material issued from the expander and was not suitable for any further evaluation.

This experiment shows that to achieve a preserved meat-like textured product, the infusion must take place after the extrusion process rather than before or simultaneously.

Example 13 A product was prepared as in Example 3.

Part of this was glazed as in Example 4, the remainder being unglazed.

A consumer preference panel of 31 people was shown the two products and asked for their preference. 25 (80r/o) of the panel members showed a strong preference for the glazed product. Reasons for preferences were that the glazed product looked moister, fresher, juicier and generally more appetising.

Example 14 The infused chunks prepared as in Example 9 were glazed with the following preserved glaze: Water 40 Gelatin 25 Glycerol 34.8 Potassium sorbate 0.2 100.0 Nine parts of infused lump were coated with one part of preserved glaze, The glazed lumps had the moist appearance of meat chunks, WHAT WE CLAIM IS: 1. Meat-like textured vegetable protein, having a moisture content of 15% to 50% by weight of final product, rendered palatable to pets and stable to microbiological spoilage by infusing textured vegetable protein as hereinbefore defined with a solution of enzymatically digested meat, digested meat offal or digested meat by-products as hereinbefore defined and with a preserving solution.

2. Meat-like protein as claimed in claim 1 in which the preserving solution contains a polyhydric alcohol as herein defined, 3. Meat-like protein as claimed in claim 2 in which the polyhydric alcohol is glycerol, sorbitol, mannitol, propylene glycol or 1,3-butanediol.

4. Meat-like protein as claimed in claim 2 or 3 in which the amount of polyhydric alcohol is below 4% by weight, 5. Meat-like protein as claimed in any of claims 1 to 4 in which the preserving solution contains sugar as herein defined.

6. Meat-like protein as claimed in claim 5 in which the amount of sugar is below 15% by weight, 7. Meat-like protein as claimed in any of claims 1 to 6 coated with a preserved gel.

8. Meat-like protein as claimed in any of claims 1 to 7 showing a density of below 0.25 ounces per cubic inch.

9. Meat-like protein as claimed in claim 1 and substantially as herein described with reference to and as illustrated in any of Examples 1 to 8.

10. Meat-like protein as claimed in claim 1 and substantially as herein described with reference to and as illustrated in any of Examples 9 to 14.

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

Claims (10)

**WARNING** start of CLMS field may overlap end of DESC **. Example 14 The infused chunks prepared as in Example 9 were glazed with the following preserved glaze: Water 40 Gelatin 25 Glycerol 34.8 Potassium sorbate 0.2 100.0 Nine parts of infused lump were coated with one part of preserved glaze, The glazed lumps had the moist appearance of meat chunks, WHAT WE CLAIM IS:

1. Meat-like textured vegetable protein, having a moisture content of 15% to 50% by weight of final product, rendered palatable to pets and stable to microbiological spoilage by infusing textured vegetable protein as hereinbefore defined with a solution of enzymatically digested meat, digested meat offal or digested meat by-products as hereinbefore defined and with a preserving solution.

2. Meat-like protein as claimed in claim 1 in which the preserving solution contains a polyhydric alcohol as herein defined,

3. Meat-like protein as claimed in claim 2 in which the polyhydric alcohol is glycerol, sorbitol, mannitol, propylene glycol or 1,3-butanediol.

4. Meat-like protein as claimed in claim 2 or 3 in which the amount of polyhydric alcohol is below 4% by weight,

5. Meat-like protein as claimed in any of claims 1 to 4 in which the preserving solution contains sugar as herein defined.

6. Meat-like protein as claimed in claim 5 in which the amount of sugar is below 15% by weight,

7. Meat-like protein as claimed in any of claims 1 to 6 coated with a preserved gel.

8. Meat-like protein as claimed in any of claims 1 to 7 showing a density of below 0.25 ounces per cubic inch.

9. Meat-like protein as claimed in claim 1 and substantially as herein described with reference to and as illustrated in any of Examples 1 to 8.

10. Meat-like protein as claimed in claim 1 and substantially as herein described with reference to and as illustrated in any of Examples 9 to 14.