GB1587150A

GB1587150A - Process for the production of proteinaceous products

Info

Publication number: GB1587150A
Application number: GB5024677A
Authority: GB
Original assignee: BP PLC
Current assignee: BP PLC
Priority date: 1978-05-26
Filing date: 1978-05-26
Publication date: 1981-04-01

Description

(54) PROCESS FOR THE PRODUCTION OF PROTEINACEOUS PRODUCTS (71) We, THE BRITISH PETROLEUM COMPANY LIMITED, of Britannic House, Moor Lane, London, EC2Y 9BU, a British Company, 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 is concerned with a process for the production of shaped cohesive textured products from a finely divided protein of microbial origin.

Processes are known for the production of shaped cohesive textured products from protein of animal, vegetable or microbial origin. In such processes the protein can be extruded to form fibres, or sheets or formed into a heat coagulable dough-like material which is then heated to give chunks. The product of these processes can be made to resemble meat. The meat like products have been termed meat analogues.

The present invention provides a process for the manufacture of a shaped cohesive textured product from a finely divided protein of microbial origin.

Accordingly the present invention is a process for the production of a shaped cohesive textured product from a finely divided protein of microbial origin which comprises mixing the finely divided protein in the presence of sufficient liquid to form a dough and passing the dough through a three roll sheeter or bar former in which the peripheral speed of the feed rolls is greater than that of the former roll and is such as to form the dough into a cohesive textured, laminated sheet or bar having a thickness of at least 0.25 inches, each lamina being formed from the dough material.

Any type of finely divided non textured microbial protein can be used as the starting material in the present process. The protein can be in the form of a powder, paste, slurry or suspension in a liquid. Preferably the maximum particle size of the finely divided protein measured at the greatest dimension of the particle is 1000 microns. Most suitably the particle size can be in the range 1 to 500 microns measured at the greatest dimension and preferably in the range 1 to 350 microns. Examples of microbial proteins are single cell protein consisting of or derived from yeast and bacteria or multicellular protein consisting of or derived from the filamentous fungi. The process is particularly useful for the production of textured meat analogues from single cell protein, e.g. yeast or bacterial protein.Single cell protein is a term which is used in the art to describe protein consisting essentially of single cell micro-organisms such as yeast or bacteria or protein extracted from microbial cells. Many processes for the production of micro-orgamsms are known. In general such processes comprise cultivating in the presence of a gas containing free oxygen, a micro-organism in a broth comprising an aqueous nutrient medium and a carbon and a nitrogen source. Traditionally the carbon source is a carbohydrate, however, recently processes have been developed in which a hydrocarbon or oxidised hydrocarbon is used as the carbon source. The hydrocarbon can be liquid or gaseous. The oxidised hydrocarbon can be an alcohol e.g. a G to Cs aliphatic alcohol and in particular methanol.

Hydrocarbon or oxidised hydrocarbon grown yeast or bacteria are particularly suitable for use as the protein in the present process. Examples of yeast can be selected from the genus Candida, e.g. Candida lipolytica or tropicalis. Examples of bacteria are methane or methanol utilising bacertia, e.g. bacteria selected from the genera Methylococcus, Methylomonas, or Methylob acter. Methylococcus capsulatus is an example of a bacterium selected from the genus Methylococcus. The yeasts can be obtained from known fermentation processes in which liquid hydrocarbons or oxidised hydrocarbons, e.g. liquid n-paraffins or alcohols such as methanol have been used as the carbon source. The methane or methanol utilising bacteria can be obtained from known processes in which methane or methanol has been used as the carbon source.

The protein/liquid mixture can contain additional solid components. Some exam ples of these additional solid components are flour, e.g. wheat flour, starch, e.g. corn starch, whey, sugars, tallow and gluten, e.g.

wheat gluten, and plant sugars, e.g. sucrose.

Most suitably the additional solid component should be present in the mix in a finely divided state, e.g. a powder. Most suitably the particle size of the additional component and of the finely divided microbial protein can be of a similar order.

Most suitably where the protein is a single cell protein the additional component can be present in the mix in a proportion of up to 75 percent by weight in relation to the total solids on a dry weight basis. The protein/liquid mix can contain the following components, up to 50 percent by weight of flour, up to 20 percent by weight of sugar, e.g. sucrose, and up to 10 percent by weight of a liquid other than water such as a humectant, e.g. propylene gylcol. A preferred mix can comprise single cell protein, e.g. a yeast and preferably a hydrocarbon grown yeast, flour and gluten. The single cell protein can be present in the mix in a proportion in the range 35 to 85 percent, the flour in a proportion in the range 5 to 50 percent and the gluten in a proportion in the range 5 to 50 percent and preferably 5 to 25 percent.The percentages being on a dry weight basis in relation to the total solids present. A particularly suitable formulation comprises 85 percent yeast, 10 percent flour and 5 percent gluten (dry weight). Mostly suitably the protein and the additional solids can be in powdered form.

Any edible liquid can be the liquid present in the mix from which the dough can be formed. The liquid is usually water, however it can contain or consist of a humectant, e.g.

a polyol such as glycerol or propylene glycol, a preservative, e.g. a fatty acid or sorbic acid, or a vegetable oil, e.g. corn oil.

Some further examples of liquids are alcohols or glycols.

Important factors in the formation of the dough are the ratio of solid to liquid present, i.e. the moisture content of the mix and the amount of mixing applied. There is an upper limit to the moisture content of the mix above which a dough cannot be formed.

This limit will vary with the nature of the solids present in the mix. Where the protein is in the form of a powder, liquid must be added to facilitate dough formation. On the other hand where the protein is in the form of a paste, suspension or slurry the liquid to solid content must be decreased to facilitate dough formation. This can be done by increasing the solid to liquid content of the mix by evaporation of liquid or by the addition of solid, e.g. protein, and/or an additional solid component of the type previously described. The suspension or slurry of protein can be an aqueous microbial cream recovered after separation, for example by centrifugation, from a fermentation broth containing micro-organisms of at least part of the aqueous phase.The microbial cream recovered after centrifugation of a fermentation broth usually has a solid content in the range 10 to 18 percent by weight (dry weight) in relation to the total weight of the cream. The solid content of the cream can be increased to 25 to 35 percent by weight (dry weight) by heating and centrifugation and/or the use of an evaporator. Alternatively, further solids, e.g. the protein and/or an additional solid component of the type previously described can be added. The optimum quantity of liquid to solid in the mix and amount of mixing required to form the dough can be determined empirically for each mix by a few simple experiments. The liquid content of the mix can be in the range 40 to 60 percent by weight and preferably in the range 45 to 50 percent by weight in relation to the total weight of the mix.When the protein is a single cell protein, e.g. yeast, the ratio of solid (dry weight) to liquid present in the mix is usually in the range 60-40 to 40-60 parts by weight. A preferred ratio is in the range 50-55 to 45-50. A preferred mix comprises 53 parts of solids (dry weight) and 47 parts of liquid by weight.

The protein/liquid mix can be formed into a dough by any known method of mixing, preferably in the absence of pressure. The amount of mixing can be critical. Mixing must be sufficient to give a dough. Insufficient mixing can leave the protein in too fine a state of communition for the present process. Mixing can be carried out by hand or by a mixing apparatus. Since pressure is not required the mixing apparatus can be simple. Some examples of suitable mixers are Z blade mixers, e.g. the Winkworth Z blade mixer, Planetary Action Bowl Mixers, e.g.

the Morton mixer Model BH 20 or the Kenwood Chef Model A.701A or Mixer Modifiers, e.g. the Oakes 4 D mixer modifier. "Morton", "Kenwood" and "Oakes" are Registered Trade Marks. The types of mixing given by these mixers are known as Z blade, planetary and screw mixing. The Mixer Modifiers are particularly suitable for continuous operation. This type of Mixer comprises a cylindrical barrel having a rotatable shaft located axially in the barrel.

Part of the shaft forms a dry powder feed screw followed by a mixing rotor or rotors which project laterally from the shaft. The inner wall of the barrel has inwardly projecting stators. The rotor or rotors are located so as to rotate between the stators. In addition the barrel can have apertures through which a liquid can be injected.

The mixing temperature does not appear to be critical. Ambient temperature is convenient. However, when the intention is to chill or freeze the textured product of the process the temperature of the components of the mix can be about 4"C. On the other hand if the textured product is to be cooked or retorted the components used to form the mix can be heated. Most suitably the temperature of the components can be in the range 60"C to 70"C.

The dough is formed into a cohesive textured laminated sheet or bar having a thickness of at least 0.25 of an inch by passing it through a three roller sheeter or bar former in which the peripheral speed of the feed rolls is greater than that of the former roll.

This differential peripheral speed between the feed and former rolls causes pressure to be exerted on the dough in the cavity defined by the rolls as it passes through the sheeter or bar former which gives a cohesive, textured, laminated sheet or bar having a thickness of at least 0.25 inches. The sheet or bar thus formed consists essentially of a plurality of laminae which are compressed together. Each lamina usually has a thickness in the range 0.03 to 0.07 of an inch and an average thickness of about 0.05 of an inch. In this respect the laminated sheets or bars of the present process resemble the structure of cooked meat.

The pressure exerted on the dough in the cavity defined by the rolls of the sheeter or bar former is small in comparison with the pressures applied in conventional extrusion and compression techniques for the production of shaped cohesive textured products.

The so called "confectionary" type compression is quite adequate for the present process. The pressure can be in the range 5 to 50 Ibs per square inch and most suitably can be in the range 10 to 20 Ibs per square inch, and preferably is about 15 Ibs per square inch.

The peripheral speed of each of the feed rolls can be and preferably is the same.

However, the speed can be different.

Peripheral speed of the feed rolls must be greater than that of the former roll. Each feed roll can have a peripheral speed in the range 10 to 100 percent greater than that of the former roll and preferably at least 25 percent greater than that of the former roll.

Most suitably the angular velocities of the rolls can be in the range 1 to 5 revolutions per minute and preferably in the range 1.5 to 3 revolutions per minute. The precise speeds will depend upon the nature of the dough to be sheeted. The peripheral speeds of the feed rolls relative to the former roll does not appear to affect the cohesive texture and laminated structure of the product.

The conditions must be such as to give a cohesive textured laminated sheet or bar having a thickness of at least 0.25 of an inch.

Most suitably the thickness can be in the range 3/8 to 1 inch and preferably in the range Z to 5/8 inches.

The temperature in the cavity of the sheeter or former is not critical. Ambient temperature is satisfactory. The temperature of the product can be raised by increasing the peripheral speed of the feed rolls relatively to the former roll. Conversely the temperature can be lowered by decreasing the peripheral speed of the feed rolls relatively to the former roll. Thus, when it is intended to chill the product, for example by refrigeration for storage purposes, the difference between the peripheral speed of the feed rolls and the former roll should be maintained at the minimum required to give a cohesive, textured, laminated product.

Since high pressure is not required to form the dough into a cohesive, textured, laminated sheet or bar this step of the process can be carried out in simple conventional, commercially available, three roll sheeters or bar formers which operate at moderate pressures. An example of a suitable Bar Former is the N.I.D. Bar Former manufactured by N.I.D. Pty. of Australia.

An example of a suitable sheeter is the Vacars 3 roll marzipan sheeter. Bar formers are particularly convenient for continuous operation.

The present process is particularly suited to continuous operation using a combination of conventional equipment. A convenient apparatus for the continuous production of cohesive textured laminated bars or sheets comprises a continuous mixer, e.g. an Oakes Mixer Modifier as hereinbefore described in combination with a three roll bar former or sheeter, e.g. an N.I.D. Bar Former or sheeter as hereinbefore described. Optionally a blender, e.g. a horizontal ribbon blender can be present to pre-mix the components before mixing the blend with liquid to form the dough. A conveyor belt can be present to pick up the sheets or bars from the sheeter or former.

When a conveyor belt is present the linear speed of the belt should be the same as the linear speed of the former roll of the sheeter or bar former to prevent the sheets or bars from either stretching and snapping or from buckling. In continuous operation using a combination of conventional equipment such as that previously described a preferred feed roll and former roll angular velocity is 2.5 and 2.0 revolutions per minute respectively.

The product of the present process is in the form of sheets or bars and can be further shaped into chunks or slabs. The product can be processed in operations normally used in the food industry, e.g. canning, without loss of shape or laminated structure.

However, the dough-like consistency is lost and the product becomes firm despite an increase in the water content.

The process of the present invention is described further by reference to the following Examples.

Example I 3 kilograms (dry weight) of a yeast powder were mixed with 2.85 litres of water at ambient temperature (7"C-10"C) in a Morton planetary action bowl mixer for about 5 minutes to form a dough. The yeast powder was obtained by cultivating a hydrocarbon utilising strain of the yeast Candida lipolytica in the presence of air in a broth comprising an aqueous nutrient medium, and a liquid n-paraffin as the carbon source.

The cultivated broth was then centrifuged to obtain a cream containing yeast having a solids content of about 13 percent (dry weight). The cream was dried in a spray drier to give the yeast powder in which the average size of the particles is 100 microns when measured at the greatest dimension of the particles.

The dough was then passed through the nip of the feed rolls of a N.I.D. Pty. of Australia 16 inch Bar Former. The Bar Former consists essentially of a pair of serrated feed rolls and a former roll having grooves. Each feed roll was rotated at an angular velocity of 2.5 r.p.m. and the former roll was rotated at an angular velocity of 2.0 r.p.m. The pressure applied to the dough in the cavity defined by the three rolls was about 15 Ibs per square inch. The temperature was 25 C. Cohesive, textured laminated bars consisting essentially of yeast were recovered from the Former. Each bar had a thickness of 0.5 of an inch. The laminac were compressed together in the bar but could be peeled apart by hand. In this respect the structure was similar to that of cooked meat. Each lamina had a thickness of about 0.05 of an inch.The bars were cut into a inch cubes by means of a guillotine. The cubes were mixed with meat and offal, canned and retorted at a temperature of 121"C and at a pressure of 15 Ibs per square inch for 60 minutes. This treatment is essentially similar to the treatment of meat in canning operations. The retorted cubes retained their cohesive texture and laminated structure but lost the dough-like consistency and became firm despite an increase in the water content from about 47 percent to about 70 percent.

Example 2 2550 grams (dry weight) of the yeast powder obtained by the technique described in Example 1, 300 grams of plain wheat flour and 150 grams of vital wheat gluten were blended together in a Morton planetary mixer. 2.4 litres of water were then added and mixing was continued for approx- imately 5 minutes to form aggregates having a dough-like consistency.

The aggregates were then passed through a N.I.D. Bar Former in accordance with the procedure described in Example 1. Cohesive textured bars having a laminated structure and a dough-like consistency were recovered from the Former. The bars had a thickness of 0.5 of an inch. The laminae were compressed together in the bar but could be peeled apart by hand. In this respect the structure was similar to that of cooked meat. Each lamina had a thickness of about 0.05 of an inch. The bars were cut into d inch cubes which were then retorted in a can with meat in accordance with the procedure described in Example 1. The chunks retained their cohesion, texture and laminated structure but lost the dough-like consistency and became firm despite an increase in water content. The retorted chunks were more resistant to breaking than those described in Example 1.

Example 3 85 parts by weight (dry weight) of the yeast powder obtained by the technique described in Example 1, 10 parts by weight of flour and 5 parts by weight of gluten were blended together. The blend was then fed continuously at a rate of 30 kilograms per hour to the inlet of an Oakes 4 D mixer modifier. The mixer consists essentially of a horizontal cylindrical barrel having three stators, ports for the injection of liquid and an axial rotatable shaft having a dry powder feed screw and six rotors located thereon.

The rotors were propellers and the stators were pins arranged alternately to the rotors.

The shaft was rotated at a speed of 300 revolutions per minute. Water was fed through the injection ports to the mix in the barrel at a rate of 23.5 litres per hour. The mix was formed into aggregates having a dough-like consistency and measuring 3 to 35 millimetres at the greatest dimension.

The dough-like aggregates from the mixer were passed continuously through a N.I.D.

Bar Former where they were formed into bars in accordance with the procedure described in Example 1 and the bars cut into cubes. The cubes were similar in cohesion, structure, texture and appearance to those described in Example 1.

Example 4 Aggregates having a dough-like consistency were prepared by the procedure described in Example 3. The dough-like aggregates formed by the Oakes mixer were fed continuously to the nip of a three roll Vicars marzipan sheeter. The gap between the second and third rolls was 7/16 inches.

Each of the feed rolls were rotated at an angular velocity of 2.5 revolutions per minute and the former roll was rotated at an angular velocity of 2.0 revolutions per minute. The pressure applied to the dough in the cavity defined by the three rolls was of the order of 10 pounds per square inch. The temperature was about 25"C. A cohesive textured sheet having a laminated structure and a dough-like consistency was recovered from the sheeter. The sheet was 0.5 of an inch thick. The laminae were compressed together in the bar but could be peeled apart by hand. In this respect the structure was similar to that of cooked meat. Each lamina had a thickness of about 0.05 of an inch.

Example 5 2550 grams (dry weight) of the yeast powder obtained by the technique described in Example 1, 300 grams of plain wheat flour and 150 grams of vital wheat gluten were blended together in a Morton planetary mixer. 2.4 litres of water were added to the blend which was mixed for 5 minutes to form aggregates having a dough-like consistency and a size distribution measured at the greatest dimension of each aggregate in the range 5 to 40 millimetres.

The aggregates were passed through a N.I.D. Bar Former and cut into chunks in accordance with the procedure described in Example 1. The chunks were 0.5 of an inch thick.

The chunks were cohesive textured and had a laminated structure and a dough-like consistency. Each lamina was about 0.05 of an inch in thickness. The laminae were compressed together in the bar but could be peeled apart by hand. In this respect the structure was similar to that of cooked meat.

The chunks were retorted using the conditions described in Example 1. The retorted chunks retained their cohesion and texture and laminated structure but lost their dough-like consistency and became firm despite an increase in water content.

Example 6 2550 grams (dry weight) of a yeast powder obtained by the technique described in Example 1, 300 grams of flour and 150 grams of gluten were mixed with 2.4 litres of water at ambient temperature in a Morton planetary action bowl mixer. Mixing was continued in the absence of pressure for about 5 minutes to form the yeast flour and gluten into aggregates having a dough-like consistency and having a size distribution measured at the greatest dimension of each aggregate in the range 5 to 40 millimetres.

The aggregates were then passed continuously through a N.I.D. Bar Former and cut into cubes in accordance with the procedure described in Example 1. The cubes had a similar structure and texture and consistency to those described in Example 1.

The cubes were mixed with meat and offal, canned and retorted at a temperature of 121"C and at a pressure of 15 Ibs per square inch for 60 minutes. This treatment is essentially similar to the treatment in canning operations. The retorted cubes retained their laminated structure, cohesion and texture.

WHAT WE CLAIM IS: 1. A process for the production of a shaped cohesive textured product from a finely divided protein of microbial origin which comprises mixing the finely divided protein in the presence of sufficient liquid to form a dough and passing the dough through a three roll sheeter or bar former in which the peripheral speed of the feed rolls is greater than that of the former roll and is such as to form the dough into a cohesive, textured, laminated sheet or bar having a thickness of at least 0.25 inches, each lamina being formed from the dough material.

2. A process as claimed in claim 1 in which the maximum particle size of the finely divided microbial protein measured at the greatest dimension of the particle is 1000 microns.

3. A process as claimed in either claim 1 or claim 2 in which the particle size of the finely divided microbial protein is in the range 1 to 500 microns measured at the greatest dimension of the particle.

4. A process as claimed in any one of the preceding claims in which the particle size of the finely divided microbial protein measured at the greatest dimension of the particle is in the range 1 to 350 microns.

5. A process as claimed in any one of the preceding claims in which the finely divided microbial protein is single cell protein.

6. A process as claimed in claim 5 in which the single cell protein consists of or is derived from a yeast or a bacterium.

7. A process as claimed in claim 6 in which the yeast is a hydrocarbon or oxidised hydrocarbon grown yeast.

8. A process as claimed in any one of the preceding claims in which an additional solid component is present in the mixture of protein and liquid in the formation of the dough.

9. A process as claimed in claim 8 in which the additional solid component is wheat flour, starch, whey, a sugar, tallow or gluten.

10. A process as claimed in claim 8 or claim 9 in which the additional solid component is present in the mixture in a finely divided state.

11. A process as claimed in any one of claims 8 to 10 in which the mixture comprises a single cell protein in a proportion in the range 35 to 85 percent, flour in a proportion in the range 5 to 50 percent and gluten in a proportion in the range 5 to 50 percent by weight (dry weight) in relation to the total weight of single cell protein, flour and gluten.

12. A process as claimed in any one of claims 8 to 11 in which the mixture comprises 85 percent yeast, 10 percent flour and

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Claims

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temperature was about 25"C. A cohesive textured sheet having a laminated structure and a dough-like consistency was recovered from the sheeter. The sheet was 0.5 of an inch thick. The laminae were compressed together in the bar but could be peeled apart by hand. In this respect the structure was similar to that of cooked meat. Each lamina had a thickness of about 0.05 of an inch.

Example 5

2550 grams (dry weight) of the yeast powder obtained by the technique described in Example 1, 300 grams of plain wheat flour and 150 grams of vital wheat gluten were blended together in a Morton planetary mixer. 2.4 litres of water were added to the blend which was mixed for 5 minutes to form aggregates having a dough-like consistency and a size distribution measured at the greatest dimension of each aggregate in the range 5 to 40 millimetres.

The aggregates were passed through a N.I.D. Bar Former and cut into chunks in accordance with the procedure described in Example 1. The chunks were 0.5 of an inch thick.

The chunks were cohesive textured and had a laminated structure and a dough-like consistency. Each lamina was about 0.05 of an inch in thickness. The laminae were compressed together in the bar but could be peeled apart by hand. In this respect the structure was similar to that of cooked meat.

The chunks were retorted using the conditions described in Example 1. The retorted chunks retained their cohesion and texture and laminated structure but lost their dough-like consistency and became firm despite an increase in water content.

Example 6

2550 grams (dry weight) of a yeast powder obtained by the technique described in Example 1, 300 grams of flour and 150 grams of gluten were mixed with 2.4 litres of water at ambient temperature in a Morton planetary action bowl mixer. Mixing was continued in the absence of pressure for about 5 minutes to form the yeast flour and gluten into aggregates having a dough-like consistency and having a size distribution measured at the greatest dimension of each aggregate in the range 5 to 40 millimetres.

The aggregates were then passed continuously through a N.I.D. Bar Former and cut into cubes in accordance with the procedure described in Example 1. The cubes had a similar structure and texture and consistency to those described in Example 1.

The cubes were mixed with meat and offal, canned and retorted at a temperature of 121"C and at a pressure of 15 Ibs per square inch for 60 minutes. This treatment is essentially similar to the treatment in canning operations. The retorted cubes retained their laminated structure, cohesion and texture.

WHAT WE CLAIM IS: 1. A process for the production of a shaped cohesive textured product from a finely divided protein of microbial origin which comprises mixing the finely divided protein in the presence of sufficient liquid to form a dough and passing the dough through a three roll sheeter or bar former in which the peripheral speed of the feed rolls is greater than that of the former roll and is such as to form the dough into a cohesive, textured, laminated sheet or bar having a thickness of at least 0.25 inches, each lamina being formed from the dough material.
2. A process as claimed in claim 1 in which the maximum particle size of the finely divided microbial protein measured at the greatest dimension of the particle is 1000 microns.
3. A process as claimed in either claim 1 or claim 2 in which the particle size of the finely divided microbial protein is in the range 1 to 500 microns measured at the greatest dimension of the particle.
4. A process as claimed in any one of the preceding claims in which the particle size of the finely divided microbial protein measured at the greatest dimension of the particle is in the range 1 to 350 microns.
5. A process as claimed in any one of the preceding claims in which the finely divided microbial protein is single cell protein.
6. A process as claimed in claim 5 in which the single cell protein consists of or is derived from a yeast or a bacterium.
7. A process as claimed in claim 6 in which the yeast is a hydrocarbon or oxidised hydrocarbon grown yeast.
8. A process as claimed in any one of the preceding claims in which an additional solid component is present in the mixture of protein and liquid in the formation of the dough.
9. A shaped cohesive textured product as hereinbefore described with reference to any one of the Examples.

9. A process as claimed in claim 8 in which the additional solid component is wheat flour, starch, whey, a sugar, tallow or gluten.

10. A process as claimed in claim 8 or claim 9 in which the additional solid component is present in the mixture in a finely divided state.

11. A process as claimed in any one of claims 8 to 10 in which the mixture comprises a single cell protein in a proportion in the range 35 to 85 percent, flour in a proportion in the range 5 to 50 percent and gluten in a proportion in the range 5 to 50 percent by weight (dry weight) in relation to the total weight of single cell protein, flour and gluten.

12. A process as claimed in any one of claims 8 to 11 in which the mixture comprises 85 percent yeast, 10 percent flour and

5 percent gluten by weight (dry weight) in relation to the total weight of yeast, flour and gluten in the mixture.

13. A process as claimed in any one of the preceding claims in which the content of liquid in the mixture of protein and liquid in the formation of the dough is in the range 40 to 60 percent by weight in relation to the total weight of the mixture.

14. A process as claimed in any one of the preceding claims in which the protein is a single cell protein which is present in the mixture of protein and liquid in the formation of the dough in a ratio of protein weight) to liquid in the range 60-40 to 40-60 parts by weight.

15. A process as claimed in any one of the preceding claims in which mixing to form the dough takes place in the absence of pressure.

16. A process as claimed in any one of the preceding claims in which the peripheral speed of each of the feed rolls is in the range 10 to 100 percent greater than that of the former roll.

17. A process as claimed in claim 16 in which the peripheral speed of each of the feed rolls is at least 25 percent greater than that of the former roll.

18. A process as claimed in any one of the preceding claims in which the angular velocity of the feed and former rolls is in the range t to 5 revolutions per minute.

19. A process as claimed in claim 18 in which the angular velocity of the rolls is in the range 1.5 to 3 revolutions per minute.

20. A process as claimed in either claim 18 or claim 19 in which operation is continuous and the angular velocity of each feed roll is 2.5 revolutions per minute and the angular velocity of the former roll is 2 revolutions per minute.

21. A process as claimed in any of the preceding claims in which the pressure applied to the dough in the cavity defined in the sheeter or bar former by the feed and former rolls is in the range 5 to 50 Ibs per square inch.

22. A process as claimed in claim 21 in which the pressure on the dough in the cavity is in the range 10 to 20 Ibs per square inch.

23. A process as claimed in either claim 21 or claim 22 in which the temperature of the dough in the cavity is ambient temperature.

24. A process as claimed in any one of the preceding claims in which each lamina in the laminated sheet or bar has a thickness in the range 0.03 to 0.07 of an inch.

25. A process as claimed in any one of the preceding claims in which the sheet or bar has a thickness in the range 3/8 to 1 inch.

26. A process as claimed in claim 25 in which the thickness of the sheet or bar is in the range f to 5/8 of an inch.

27. A process as hereinbefore described with reference to any one of Examples 1 to 6.

28. A shaped cohesive textured product when produced by the process as claimed in any one of the preceding claims.