IES61544B2 - Process for the preparation of a food product - Google Patents

Description

APPLICATION No β^ Ο97** PROCESS FOR THE PREPARATION OF A FOOD PRODUCT This invention relates to a process for th© preparation of a food product.. In particular, it relates to the preparation of a meat-like food product 5 for human or animal consumption.

According to the present invention there is provided a process for the preparation of a meat-like food product, which process comprises (a) partially cooking a vegetable protein at a temperature in the range of from about 120°C to 190°C, optionally adding a meat or meat product or a mixture thereof in comminuted form and (b) further cooking the resulting product at a temperature in the range of from about 120°C to 135°C, and at a pressure not greater than 10 bar (1000 kPa) and (c) extruding the food product thus prepared.

The temperature in step (a) is preferably from 150°C to 170°C, especially about 160°C. The temperature in step (b) is preferably from 123°C to 131°c, especially about 130°C and the pressure is preferably from 5 to 9 bar (500 to 900 kPa), more preferably from 7 to 9 bar (700 to SOO kPa) The extruded food product is preferably cut into discrete pieces before use.

Examples of suitable sources of vegetable proteins are wheat flour, wheat gluten, maize flour,, maize gluten, soya flour, soya bean and mixtures thereof. -- s 6 1 54 4 ~ 2 The tern neat” as used herein includes animal neat such as, for example, beef, lamb and pork, fish, chicken and offal. The term Meat products” as used herein includes fish meal, chicken meal, pork rinds, fresh blood, dried blood, blood albumen, rind emulsion and greaves.

The food product obtained according to the process of the invention nay additionally contain conventional colouring agents and flavouring agents such as cheese, vegetables and cereals etc. Examples of suitable cereals are wheat, maize, pollard and barley.

The invention will now be. described in more detail with reference to the accompanying drawing which shows an apparatus, partially in cross-section, used in the process of the invention, the apparatus being a high-temperature/short-time twin screw extruder.

The apparatus comprises & holding bin 1 for containing the vegetable protein and from which th* vegetable protein is discharged continuously and uniformly to a variable speed conditioning/feeding device 2. The vegetable protein is partially cooked in the conditional/feeding device 2 at a temperature in the range of from about 120°C to 190°C, preferably from 150°C to 170°C and most preferably about 160°C. The partially cooked vegetable protein is fed from the device 2 at the desired production rate to an extruder 3. Where a meat or meat product or mixture thereof is to be included in th® food product, the meat/meat products are fed directly into the extruder 3 following comminution via an Injection nozzle 4. Moisture is added via an injector 5.

The extruder 3 comprises a series of heads 6 and screws 7. The screws 7 comprise transport sections 8, polygons 9 and reverse screws 10, which are chosen to properly feed, knead and further cook the process ingredients. The extruder 3 is driven by a variable speed motor 11 through a gearbox 12...

At the discharge end of the extruder 3, there is a die plate 13 having a plurality of apertures (not shown) through which the cooked ingredients are extruded in the form of strands. The apertures of the die plate 13 may be of any suitable siae and preferably have a diameter in the range of from 3 ma to 15 ma. on extrusion, the pressure generated within the system is released and the food product expands. The strands are cut to the desired length by a variable speed knife 14 which rotates at the discharge face of the die plate 13. The cut pieces are then fed into a forced air drier/cooler (not shown), dried and cooled.

The screws 7 in the extruder 3 subject the food product ingredients to elevated temperatures and pressure and high mechanical shear. Heat may arise solely from the shear within the system and/or be applied from an external source, for example by means of steam jackets, electrical heaters or oil circulation. Water may be added to the process ingredients during the extrusion process. The configuration of the screws 7, polygons 9, heads 5 and reverse screws 10 within the extruder 3 is selected so that the desired temperature and pressure, may be achieved so as to produce a product with th® desired final density, texture and rehydration characteristics. Th® heat and attrition thus produced cans® the destruction of the protein bonds and then realignment of the proteins in a linear configuration. The design of the die plate 13 is such as to allow the realignment of the proteins in a linear configuration. An expansion chamber (not shown) immediately behind the die plate 13 allows the proteins to settle after their destruction and before entering the die plate 13.. The die plate 13 has a compression chamber (not shown) leading to the discharge end which exerts pressure causing the proteins to realign in a linear conf iguration.

The temperature within the extruder 3 is critical for the process and should be in the range of from about 120°C to 135°C, preferably from 123°C to 131°C, the optimum temperature being about 130°C. The pressure is also critical and should not be greater than 10 bar (1000 kPa).. Significant deviation upwards from these temperatures and pressure causes deterioration of the food product.

The meat-like product prepared according to the invention is. suitable for incorporation into a wide variety of conventional animal and human food processing operations, 'when the food product of the invention was canned and subjected to both static and agitating retort processing at conventional canning temperatures (116°C,, X21°C and 126QC) the discrete meat-like pieces retained their shape and integrity. Water was absorbed in a ratio of not less than 3:1 (water to product), the food product having a bulk density in the range of from 300 to 400 g/1. The food product obtained according to the invention was also found to have a high degree of palatability, when fed i to animals. Upon storage in dry conditions, there was no apparent deterioration of the product, which may be stored at ambient temperature for up to nine months.

The invention is further illustrated by the following Examples in which, percentages are given by weight™ The process of the invention was carried out on a Buhler DNDG twin screw extruder.

EXAMPLE 1 Ingredients: Mieat Gluten 55% Maize Four 45% The above ingredients were mixed together, conditioned in the device 2 and then fed into the extruder 3. The extruder speed was 450 r.p.m. Water was injected directly into the extruder at a rate of litres/minute. The temperature within the extruder 20 barrel section was 127°C and the pressure was 9 bar (900 kPa).

The product obtained under these conditions was a very meat-like, firm, well textured and palatable 25 foodstuff which, when canned as an ingredient in a conventional petfood, was retort stable. The product bulk density was 330 g/1.

EXAMPLE 2 Ingredients: Wheat Gluten 50% Maiae Four 40% Fresh Liver 10% The above ingredients were mixed together, conditioned in the device 2 and then fed into the extruder 3.. The extruder speed was 456 r.p.ia. Water was injected directly into the extruder at a rate of 22 litres/minute. The temperature within the extruder barrel section was 123°C and the pressure was 7 bar (700 kPa).

The product obtained under these conditions was a very neat-like, firn and well textured product. When canned as an ingredient in a conventional petfood it was palatable and retort stable. The bulk density of the product was 300 g/1.

The invention ie not United to the embodiments described herein which nay be modified or varied without departing from the scope of the invention.

Claims (4)

1. CIAIMS: 1™ A process for the preparation of a meat-like food product, which process comprises (a) partially 5 cooking a vegetable protein at a temperature in the range of from about 120°C to 190°C, optionally adding a meat or meat product or a mixture thereof in comminuted form and (b) further cooking the resulting product at a temperature in the range of from about 120°C to 135°c, 10 and at a pressure not greater than 10 bar (1000 kPa) and (c) extruding the food product thus prepared and optionally cutting it into discrete pieces.

2. A process as claimed in claim 1 in which the 15 temperature in step (a) is. from 150°C to 170°C, preferably about 160°C; the temperature in step (b) is from 123°C to 131°C, preferably about 130°C; and the pressure in step (d) is from 5 to 9 bar (500 to 900 kPa), preferably from 7 to 9 bar (700 to 900 kPa).

3. A process as claimed in claim 1 or 2 in which the vegetable protein is selected from wheat flour, wheat gluten, maize flour, maize gluten and mixtures thereof.

4. A process as claimed in any one of claims 1 to 3, in which a meat or meat product is added prior to step (b). 30 5« A meat-lik© food product obtained by a process as claimed in any preceding claim and which additionally includes a colouring agent and/or flavouring agent.