IE54741B1 - Food product and method and apparatus for its manufacture - Google Patents

Abstract

A proteinaceous food product particularly a period is made by forming a finely divided mix or emulsion containing proteinaceous materials, adding a water soluble gel-forming agent and forming the mix or emulsion into discrete pieces. Before and/or after forming the pieces the mix or emulsion is treated with a calcium salt. The process is characterized in that the mix or emulsion contains a quantity of dry denatured greaves. Apparatus for carrying out the process is also disclosed.

Description

The invention relates to a food product and also to a method for its manufacture. The invention is particularly concerned with the manufacture of a proteinaceous food product in the form of discrete shape-retaining pieces or chunks. The product of the invention is particularly suitable for use as a pet food, particularly a dog or cat food, but is not restricted to such use and has other possible uses.

There are known processes for the manufacture of proteinaceous food products which have a chunky meat appearance and which are particularly suitable for canning as pet foods. One method of manufacturing formed meat products which subsequently may be canned is to form an emulsion of animal and/or vegtable proteins and subsequently to heat-set the protein into chunks. The use of heat-setting has a number of disadvantages which include excessive water loss and the loss of soluble proteins. There is also the possibility that heat treatment renders the food less acceptable to animals. Methods of cold-forming products into shape-retaining chunks using a jelled calcium alignate are described in U.K. Patent Specification No. 1,474,629 and U.S.

Patent Specification No. 4,348,418.

British Patent Specification No. 1,474,629 discloses and claims a method of cold-forming a proteinaceous food product in the form of discrete shape-retaining pieces which comprises forming a finely divided mix or emulsion containing animal and/or vegetable proteinaceous materials, incorporating a water soluble alignate in said -25 4 7 41 mix or emulsion, forming the said mix or emulsion into pieces of the desired shape and subsequently treating the formed pieces with an aqueous solution of a water soluble calcium salt. The British Patent Specification also describes the incorporation of a water-insoluble calcium salt into the alginate containing mix or emulsion. In this case the aqueous solution of a water-soluble calcium salt also contains an edible acid. After treatment with a solution containing calcium ions, a gelled calcium alginate skin is formed around each piece to encapsulate the proteinaceous material and retain the discrete shape of the piece.

It has been found that food pieces prepared in accordance with the method of British Patent Specification No. 1,474,629 have a soft, sticky, pasty interior and do not closely resemble meat chunks. In the examples described in Patent Specification No. 1,474,629 the mix contains cereals and/or refined meat meal, which help to adsorb water present in the mix, but detract from the desired consistency and taste of the product.

U.S. Patent Specification No. 4,348,418 discloses and claims a method of forming food products in the form of shape-retaining pieces which comprise the steps of: (a) producing an aqueous slurry of comminuted food material having a water-soluble alginate salt dissolved therein, (b) producing a slurry of a sparingly water-soluble calcium salt including as a retarding agent a member selected from the group consisting of sugar, a monohydric alcohol and a polyhydric alcohol, (c) mixing the slurries of step (a) and (b) for a time period of less than 30 seconds, (d) allowing the resulting mixture of step (c) to gel; and -35 4 7 41 (e) cutting into pieces the product of step (d), said water soluble alginate salt being present in an amount of from 0.3 to 5.0 percent by weight of said product.

In practice it has been found that improved chunks prepared by the above process do not have the necessaary firm fibrous texture of meat, and are less palatable to animals than meat.

We have surprisingly found that by incorporating dry denatured greaves in the emulsified mix a cold formed chunk may be prepared which has the consistency and texture of solid meat, and which is highly palatable to animals and is also highly nutrious.

Accordingly, we provide a process for preparing a proteinaceous food product in the form of discrete, gelled, shape-retaining pieces which comprises forming a finely divided mix or emulsion containing proteinaceous materials, adding a water soluble gel - forming material to said mix or emulsion, forming the mix or emulsion into discrete pieces and before and/or after forming said pieces treating the mix or emulsion with a calcium salt, wherein the mix or emulsion contains a quantity of dry denatured greaves in an amount of between 10 to 30% by weight of the mixture. Preferably, the amount of greaves is between 10 to 15% by weight.

The water soluble gel-forming agent may be a water soluble alginate, for example sodium alignate or a water soluble, low methoxy pectin. Suitably, the formed pieces containing the water soluble alginate are dipped in a bath containing an aqueous solution of a water soluble calcium salt.

Alternatively, or in addition, it is possible to add a sparingly soluble calcium salt e.g. calcium sulphate, into the emulsion or mix before formation of the pieces. The calcium reacts slowly with the setting agent and causes the subsequently formed pieces to set into shape-retaining chunks.

The gel-forming agent may comprise a water-soluble low methoxy pectin alone, which can also be gelled by treatment with calcium ions. In -45 4 7 41 accordance with a further embodiment of the invention, the gel-forming agent comprises a mixture of an alginate and a low methoxy pectin. He have suprisingly found that by using such a mixture, the low methoxy pectin will act to firm up the centre of the chunk while the alginate forms a gel skin around the ouside of the chunk. The reason for this is that the alignate reacts quickly with the calcium to form the outer skin, while the low methoxy pectin reacts more slowly, but continues to set after the formation of the outer skin to firm the centre of the chunk. This setting will be accelerated if the chunks are heated during canning. Another advantage of using a mixture of alginate and low methoxy pectin is that the dwell time in the bath of solution of calcium salt is reduced thus speeding-up the process.

It has been found that by using dry denatured greaces the mixture may contain a relatively high proportion of water which is absorbed by the dry denatured greaves and the dry greaves also give the chunks an improved meaty texture and flavour, and is highly nutrious. It has also been found advantageous to use guar gum in the mixture. It has been found that guar gum stiffens the mixture, increases viscosity and allows the material to move more easily through the forming apparatus. It also assists in retaining mositure in the formed pieces especially if the pieces are canned.

The examples described in U.S. Patent Specification No. 4,348,418 disclose the use of wet greaves. However, these do not offer the same advantages as the dry denatured greaves of the invention. The dry denatured greaves of the invention is prepared by dry cooking fatty animal tissue, drying the cooked tissue and while the tissue is still hot extracting the fat from the tissue using mechanical pressure. The residual dry denatured greaves is crispy with a good aroma and a palatable taste. It also has a long shelf life and can be stored without refrigeration. In contrast, wet greaves is formed by extracting the fat by rendering while steam cooking. The water moisture is retained in the residual tissue. Wet greaves has a bland taste and aroma. Further it tends to become rancid very quickly and must be stored under refrigeration.

In a preferred method according to the invention the proteinaceous -5material including dry denatured greaves is formed into an emulsion and is pumped through a forming machine which includes a forming die comprising at least one reciprocating apertured plate which moves relative to a second apertured such that the emulsified material passing through the apertures in the two plates is formed into discrete chunk shaped pieces. Preferably, the chunks are collected in a bath containing an aqueous solution of a water soluble calcium salt. The chunks float in the bath and are conveyed along the bath by means of a plurality of paddles to prevent the chunks from accumulating into a solid mass.

One embodiment of a method of the invention is hereinbefore described with reference to the accompanying drawings, wherein: Fig. 1 is a side elevation of a commerically available meat mixing machine; Fig. 2 is a side elevation of forming apparatus and Fig. 3 shows a detail of the apparatus of Fig. 2.

Referring to the drawings, a mixture typically containing dry denatured greaves, crushed bone, liver, sodium alignate, guar gum, sodium benzoate and water is finely mixed in an automatic meat mixing machine 1, as shown in Fig. 1. This machine is commercially available from K. Schnell and carries out the functions of mixing the ingredients, bowl chopping and emulsifying. Mixing, chopping and emulsifying are preferably carried out under part-vacuum. This allows water to be brought into the mixture more quickly but yet prevents a large amount of air from being incorporated in the emulsion. The presence of a small amount of air is desirable to enable the formed chunks to float as described below. The mixture is formed into an emulsion in the mixing machine and is passed into a holding tank in the form of a hopper 2 (see Fig. 2). From the holding tank the emulsion is fed to the hopper 3 of a mono pump 4. The pump 4 pumps the emulsion, under a pressure of about 20 to 25 p.s.i. (1.41 x 104 - 1.76 x 104 Kg/m2), through a pipe 5 to a forming die 6. The pipe 5 is provided with a pressure-relief valve (not shown). If there is a build up of pressure -65 4 7 41 in pipe 5 the relief valve will open to recyle the emulsion to the hopper 3.

The die 6 for forming the chunks is shown in more detail in Figure 3.

It comprises a fixed die plate 7 formed with a plurality of apertures 8. A second plate 9, having apertures 10, is slidable horizontally relative to the fixed plate 7. The plate 9 is moved by means of a reciprocating drive of an electric motor 11. During the travel of the plate 9 relative to the fixed plate 7, the holes in each plate will coincide to allow emulsion to be extruded in the form of pieces or blobs. The size of the piece extruded can be determined by controlling the speed of reciprocation of the plate 9 and the pressure in pipe 5. These parameters will largely determine the length of the piece extruded. The width or diameter of the piece extruded is determined by the size of the holes in the plate and these may be changed as desired.

The extruded pieces fall into a bath 12. The bath contains a solution of a water soluble calcium salt. The pieces or chunks float on the surface of the solution and are conveyed alsong the bath by means of paddles 13 which are driven by an endless chain 14.

The gelled chunks are removed from the bath for further processing.

The formed chunks may, for example be frozen or canned. If the chunks are canned for use as a dog or cat food the chunks are preferably mixed with a textured vegetable protein, e.g. a soya protein. A matrix may comprise a gravy made from minced meats. Suitably a heat-setting gel is added which is caused to set when heat is applied during canning.

The invention is further illustrated by the following examples, which are for exemplification only and are not intended to be limiting. All parts shown are parts by weight. -7EXAMPLE 1 A mixture containing: Dry greaves 12% Crushed bone 12% Liver 6% Sodium alginate 1.2% Guar gum 0.8% Sodium benzoate 0.3% Hater & dye 67.7% was mixed using a chopping action for 30 secs - 1 minute and passed through a 3 mm plate. The slurry was passed through a chunk forming machine under pressure and the chunks were allowed to drop into a bath containing calcium chloride (1% - 20%). The chunks were conveyed along the bath using paddles and a belt conveyor. After 10 mins, chunks made a skin strong enough to withstand processing. After 2 hours the centres of chunks had solidified.

EXAMPLE 2 A mixture containing: Dry greaves 15% Bone 10% Liver 5% Sodium alginate 1.2% Guar gum 0.8% 30 Hater 66.2% Sodium Benzoate 0.3% Calcium Sulphate 0.5% Tetra sodium pyrophosphate 0.025% was prepared as in Example 1. -85 4 7 4 1 EXAMPLE 3 A mixture was prepared containing Dry denatured greaves 15% Crushed bone 10% Liver 5% Amidated Low Methoxy! Pectin 2% Guar gum 2% Hater & dye 66% The mixture was treated as in Example 1. The pectin requires only a brief contact with the calcium chloride for setting to begin so that the dwell time in the bath can be low. The pectin has a slow response to calcium so that setting continues slowly on removal from the bath. If the chunks are canned setting will be accelerated by heating during canning.

EXAMPLE 4 A mixture containing: Dry denatured greaves 12% Crushed bone 12% Liver 6% Sodium alginate 1.0% L.M. Pectin 0.5% Guar Gum 0.8% Sodium benzoate 0.3% Water & dye 67.4% The mixture was treated as in Example 1. The alginate reacted quickly with the calcium to form a skin on the outside of the chunk, while the pectin reacted more slowly within the chunk to form up the centre of the chunk. -9EXAMPLE 5 A mixture containing: Dry greaves 15% Bone 10% Liver 5% Sodium alignate 1.2% Guar gum 0.8% Water 66.2% Sodium Benzoate 0.3% Calcium Sulphate 0.5% Tetra sodium pyrophosphate 0.025% was passed through a 3 cm plate into trays and allowed to set (typically 5 minutes to 1 hour). Slabs were diced into suitable shapes.

Claims (17)

1. A process for preparing a proteinaceous food product in the form of discrete, gelled shape-retaining pieces which comprises forming a finely divided mix or emulsion containing proteinaceous materials, adding a water soluble gel-forming agent to said mix or emulsion, forming the mix or emulsion into discrete pieces and before and/or after forming said pieces, treating the mix or emulsion with a calcium salt, wherein the mix or emulsion contains a quanity of dry denatured greaves in an amount of between 10 and 30% by weight of the mixture.

2. A process as claimed in claim 1 wherein the amount of greaves present in the mixture is between 10 and 15% by weight.

3. A process as claimed in any preceding claim wherein the water-soluble gel-forming agent is a water-soluble alginate.

4. A process as claimed in claim 3 wherein the water-soluble alginate is sodium alginate. 5. Used in the mix or emulsion.

5. A process as claimed in any preceding claim wherein the formed pieces are dipped in a bath containing an aqueous solution of a water-soluble calcium salt.

6. A process as claimed in any preceding claim wherein a sparingly soluble calcium salt is added to the mix or emulsion before the formation of the pieces.

7. A process as claimed in claim 6 wherein the sparingly soluble calcium salt is calcium sulphate.

8. A process as claimed in either of claims 1 or 2 wherein the water-soluble gel-forming agent is a water-soluble low methoxy pectin.

9. A process as claimed in claim 1 wherein the gel-forming agent comprises a mixture of an alginate and a low methoxy pectin. -1110. A process as claimed in claim 9 wherein the formation of a gel is accelerated by heating.

10. A forming die comprising at least one reciprocating apertured plate such that emulisified material passing through the apretures in the two plates is formed into discrete chunk-shaped pieces.

11. A process as claimed in any preceding claim wherein guar gum is

12. A process according to any one of the preceding claims wherein the proteinaceous material including dry denatured greaves is formed into an emulsion and is pumped through a forming machine which includes

13. A process as claimed in claim 12 wherein the chunk-shaped pieces

14. A proteinaceous food product suitable for use as a pet food 20 comprising a mixture of dry denatured greaves, crushed bone, liver and guar gum, in the form of discrete, gelled, shape-retaining chunks, in which the gel has been formed by the action of a water soluble gel-forming agent and a calcium salt. 25

15. A process for preparing a proteinaceous food product substantially as described herein with reference to the Examples. 15 are collected in a bath containing an aqueous solution of a water-soluble calcium salt and the chunks floating in the bath are conveyed along the bath by means of a plurality of paddles.

16. A proteinaceous food product substantially as described herein with reference to the Examples.

17. A proteinaceous food product whenever prepared by a process as claimed in any one of claims 1 to 13 and claim 15.