WO2002039831A1

WO2002039831A1 - A method for producing protein powder from legumes

Info

Publication number: WO2002039831A1
Application number: PCT/IB2001/002140
Authority: WO
Inventors: Pierre Guillaume Marais
Original assignee: Chemical Consultants (Pty) Ltd
Priority date: 2000-11-15
Filing date: 2001-11-14
Publication date: 2002-05-23
Also published as: AU2002215143A1

Abstract

This invention relates to a method for producing a protein powder from legumes, in particular soybeans. The method includes the steps of germinating the legume to form a cotyledon, hull and root. The step of germination is to partially hydrolyse the cell walls of the legume and to reduce oligosaccharide levels in the cotyledon. Enzymes are advantageously added to hasten the hydrolysis of the cell walls and reduction of oligosaccharide levels. Thereafter, the germinated legume may be heat treated to inactivate at least some of the enzymes. The legumes are then dried, ground, and defatted by means of solvent extraction to remove substantially all of the oil present in the legume. Thereafter, the defatted legume is milled in excess solvent, and the solvent is removed to provide a high-protein, substantially fat-free powder with reduced oligosaccharide levels.

Description

A METHOD FOR PRODUCING PROTEIN POWDER FROM LEGUMES

FIELD OF THE INVENTION

THIS invention relates to a method for producing a protein powder from legumes, typically from soybeans.

BACKGROUND TO THE INVENTION

In most developed countries, popular and important sources of food protein are meat, poultry and egg, dairy and fishing products. However, the steadily increasing cost of these animal proteins has compelled the food industry to focus attention on low-cost vegetable sources of protein, principally legumes. Of the legumes, soybeans contribute very high protein content, along with oil, carbohydrates, fibre, vitamins and minerals. Currently, no protein can be produced in such mass quantities or as economically as soybeans. A mature soybean does however have certain characteristics which render it less fit for human or animal consumption. These include certain proteins and enzymes with varying toxicity to humans and animals, and oligosaccharides.

It is known in the art to produce soybean products. From a practical point of view, soybean seeds may be considered to be composed of three parts, namely the hull (including hilum), hypocotyl (germ) and paired cotyledons. For food product purposes, the clean seeds are usually split or cracked in a manner to permit complete removal of hull, hilum and hypocotyls. This leaves pure cotyledons (approximately 90 % of the seed weight) as the source of further fractions. In the food industry, two important fractions are the proteins and lipids present in the cotyledons.

Traditionally, industrial practice consists of solvent (hexane) extraction of the lipids in the cotyledons, removing the solvent from the lipid and defatted portions, followed by further fractionation of the lipid and non-lipid portions as desired.

A method of producing a soy protein concentrate which is fat-free and oligosaccharide-free employs a solvent (usually aqueous alcohol) which selectively extracts the soluble carbohydrates (including the oligosaccharides) and other soluble low molecular weight components from the defatted crushed cotyledons whilst immobilising the protein fractions. This method suffers from the major disadvantage that the alcohol renders the protein non-functional through a process of denaturation. The result is a brittle soy protein with restricted application. Partially leaching the sugars with larger volumes of chilled water in the presence or absence of alkaline earth cations is an alternative method that has found limited application. Another method is used in producing a soy protein isolate. In this method the soy protein isolates are made from defatted flakes by extracting the protein and other solubles in aqueous or mildly alkaline aqueous media. The aqueous media is separated from their insoluble residue (mostly fibre, cellulose and hemi-cellulose) by various screening, centrifuging, or filtering devices, or combinations thereof. Thereafter, the pH of the clarified extract is lowered to the range 4 to 5 at which the solubility of the acid-precipitable protein is at a minimum. The separation of curd and whey is accomplished by one of a variety of means. The curd is usually neutralised with food grade alkali before it is spray-dried. Apart from the manufacturing cost of the soy isolate, the concomitant production of insoluble residue and diluted whey solubles, complicates the process. Soy isolates are seldom pleasant tasting and rely heavily on skilful formulation to prepare acceptable consumer products.

One of the simplest methods of converting soybeans into a high protein food is to extract or grind the beans with water to produce a beverage known as soymilk. This beverage has been a food staple in the Orient for many centuries. This product is not to be confused with soy beverages that are commercially produced from formulations using soy isolate. Traditionally, soymilk ^"is made by soaking the soybeans, grinding them in water, cooking the slurry, and then filtering the slurry. Unfortunately, the beverage produced in this manner has a distinct flavour, described as "beany" or "painty", due to the activation of the lipoxygenase enzyme when the uncooked beans are pulverised in water. In addition, this soymilk contains indigestible (to non-Asians) oligosaccharides and it has therefore not found wide acceptance in regions outside of Asia.

In the last century several methods have been developed for the manufacture of a full-fat soymilk with an agreeable flavour. A soybean milk analogue, and products made from it, is invaluable to people intolerant to lactose in cow's milk. The key step in all of these methods is to inactivate the lipoxygenase enzymes responsible for beany off-flavours by blanching the raw dehulled soybeans for at least 30 minutes before they are ground to a slurry to extract the protein with hot water and filtered to remove the insoluble fibre. Typically the soymilk is then allowed to simmer at 85-88°C in a steam-jacketed kettle for 20 minutes in order to fully inactivate trypsin inhibitors and other anti-nutritional agents, destroy micro-organisms, and improve the flavour of the product. The soymilk is formulated and homogenised to reduce the size of the fat globules and remaining insoluble materials into very fine and uniform particles by forcing them under high pressure through small openings. The soymilk is then refrigerated and sold in its "fresh" form. Alternatively, it can be subjected to ultra high temperature (UHT) treatment. Certain manufacturers spray dry the full-fat milk, but the lipids rapidly become rancid under these conditions. These products have found very limited industrial application due to their brief shelf lives.

It is an object of this invention to provide a process for producing a high- protein, substantially fat-free powder with reduced oligosaccharide levels, from legumes, typically from soybeans.

SUMMARY OF THE INVENTION

According to the invention there is provided a method for producing a protein powder from legumes, the method including the steps of: germinating the legume to, form a cotyledon, hull and root; optionally heat treating the germinated legume to inactivate at least some enzymes; drying the legume; grinding the dried legume; defatting the dried legume by means of solvent extraction which removes substantially all of the oil present in the dried legume; milling the defatted legume in excess solvent to a desired particle size; removing the solvent from the milled particles; and cooling the milled and desolventised particles. The term "legume" mentioned above may refer to the entire legume, or to the cotyledon, depending on whether or not the cotyledon has been separated from the hull and hypocotyls/roots.

Preferably, the step of germinating the legume includes the step of submerging the legume in water, in a dark enclosure, for between 2 and 10 minutes, preferably 60 seconds, at an operating temperature of between 0 and 60°C, more preferably between 25 and 30°C.

The step of germinating the legume preferably includes the hastening of enzymatic hydrolysis of the cell walls by the addition of carbohydrase enzymes, and also the step of adding enzymes which are capable of biochemically reducing levels of oligosaccharide in the legume. Although some enzymes such as pectinase and beta-galactosidase are capable of both functions, a mixture of enzymes, one or more of which are capable of hastening hydrolysis of the cell walls, and one or more of which are capable of reducing levels of oligosaccharides are added. Enzymes that are capable of hastening hydrolysis of the cell wall include lysozyme, beta- glucasidase, beta-amylase, beta-glucanase and pectinase. Enzymes that are capable of reducing ^" oligosaccharides include stachyase, exoglycosidases such as beta-galactosidase, invertase, lactase and pectinase. This step typically also includes the step of maintaining a level of antibacterial agent in the water to prevent bacterial contamination. The step of germinating the legume may be conducted over a period of 1 to 400 hours, typically 48 to 96 hours.

The method may include an initial step of disinfecting the legume with an anti-bacterial agent.

Conveniently, the step of heat treating the germinated legume comprises the step of blanching the germinated legume with boiling water or steam for a period of between 1 second and 40 minutes, usually 1 minute. Ideally, the step of heat treating the germinated legume comprises the further step of cooling the blanched legume to a temperature below approximately 65°C, most advantageously to ambient temperature or below ambient temperature.

Typically, the step of drying the legume includes drying the legume to a residual moisture content of between 0 and 30%, preferably between 4 and 7%.

Conveniently, the step of defatting the dried legume comprises the further step of recovering and refining the oil.

Advantageously, the method includes the step of dehulling the legume prior to the milling step. The dehulling step preferably takes place after the heat treatment step to recover the cotyledon which is then dried, ground, defatted and milled. The step of dehulling the heat-treated legume preferably also comprises the further step of recovering, -drying^" and milling the hull and also the step of recovering the hypocotyls/roots.

Preferably, the step of milling the defatted legume includes classifying the milled particles and remilling the oversize particles to produce a particle size of between 1 and 1000 microns, more preferably between 10 and 60 microns. If the dehulling step mentioned above does not take place, this classifying step serves to remove the hull.

Typically, the step of removing the .solvent from the milled particles includes flash evaporation on a hot drum.

Ideally, the step of cooling the milled particles includes cooling to a temperature below approximately 65°C, most advantageously to ambient temperature or below ambient temperature. The step of cooling the milled particles may occur in the presence of an inert gas. Typically, the legumes are soybeans and the method is for producing a high-protein, substantially fat-free powder with reduced oligosaccharide levels, from soybeans.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows a flow diagram of a method for producing a protein powder from legumes according to an embodiment of the invention; and

Figure 2 shows a schematic side view of a Ferris wheel arrangement forming part of the apparatus for use in the method shown in Figure 1.

An embodiment of the invention is described in detail in the following passages of the specification which refer to the accompanying drawings. The drawings, however, are merely illustrative of how the invention might be put into effect, so that the specific form and arrangement of the features shown is not to be understood as limiting on the invention.

DESCRIPTION OF AN EMBODIMENT

Figure 1 shows a flow diagram of an embodiment of a method for producing a high-protein, fat-free powder with reduced oligosaccharide levels, from legumes. In the embodiment shown in Figure 1 the legumes are soybeans, but it should be understood that they could be other legumes, or a mixture of legumes. In a preferred embodiment of the invention, the process commences with the initial step of disinfecting the soybeans with an anti-bacterial agent. The apparatus for performing this step is described in more detail later in this specification.

The step of germinating the soybeans occurs by repeatedly submerging the soybeans in water, in a dark enclosure, for between 1 second and 10 minutes, typically 60 seconds. The temperature of the water is thermostatically controlled to be at an operating temperature of approximately 25°C. The operating temperature could be between 0 and 60°C, but is preferably between 25 and 30°C. An anti-bacterial agent, typically chlorine, is used in the water to prevent bacterial contamination of the product during germination. .

The germination process must be of sufficient duration to partiallyhydrolyse the cell walls - of the legume and also to biochemically reduce the oligosaccharide levels in the cotyledon. Typically a period of 48 hours is sufficient, however, the period could be between 1 to 400 hours. During the sprouting process, the texture of the soybean is altered due to the process of partial enzymatic hydrolysis of the cell walls of the soybean. This process of enzymatic hydrolysis may be hastened by the addition of carbohydrase enzymes such as lysozyme, beta-glucosidase, beta-amylase, beta-glucanase and pectinase. Enzymes that reduce oligosaccharide (for example stachyase and raffinase) levels are also added. Such enzymes include stachyase, exoglycosidases such as beta-galactosidase, invertase, lactase and pectinase. Although some enzymes are capable of both functions, a mixture or "cocktail" of enzymes that carry out both functions is typically added. A typical mixture is a mixture of beta-galactosidase and cellulase enzymes. Certain micro-organisms that contain or secrete some of these enzymes naturally may be added at this stage. Ifmicro-organisms are used, the anti-bacterial agent is omitted from this step.

The germinated cotyledons may then be heat treated by blanching with boiling water for a period 1 minute. Steam or any form of dry heat could also be used to blanch the germinated cotyledons. The length of the heat treatment could be between 1 second and 40 minutes. The step of blanching the cotyledons has the effect of inactivating unwanted or harmful proteins and enzymes which occur naturally in soybeans, such as soybean trypsin inhibitor, hemagglutinins, lipoxygenase and urease. The blanched product is immediately cooled down to ambient temperature or below because prolonged exposure of the bean protein to moist heat may lead to an undesirable decrease in functionality as measured by Protein Dispersability Index (PDI) and Nitrogen Solubility Index (NSI).

In some cases, the step of heat treating by blanching may be omitted. The omission of this step leads to the production of a more functional protein that forms stronger and more stable emulsions with added fat and water. It is however important that the end-product then be heated, to destroy harmful enzymes before consumption. For example, if the product is used as a meat-extender, harmful soy-bean enzymes are -destroyed when the end meat product is cooked.

The apparatus for performing the abovementioned steps is now described. In one embodiment of the invention, a Ferris wheel arrangement 10 is used for the germination and blanching steps, but it should be understood that any suitable apparatus which allows for the continuous or batch-wise germination and blanching of the soybeans can be used.

The Ferris wheel arrangement is .shown more clearly in Figure 2. Each Ferris wheel 12 includes twenty ladles 14. Each ladle 14 is made from reinforced stainless steel and the base of the ladle is perforated. In the embodiment shown in Figure 2 there are two Ferris wheels, but there could be more depending on the desired capacity. A weighed amount of cleaned, dry soybeans are loaded into each ladle 14 from a discharge hopper 16. Once all of the ladles have been loaded with soybeans, chlorinated water is pumped into the basins 18 located below the Ferris wheels and the Ferris wheels are rotated so that each ladle is periodically immersed in the chlorinated water for a certain amount of time. Instead of chlorine, another anti-microbial/viral/bacterial/fungal agent may be used. In this manner the soybeans are sterilised and hydrated.

Once all of the ladles have passed through the water in the basins at least once, the water in the basins is drained and replaced by fresh water that contains hydrolytic carbohydrase enzymes. The hydrolytic carbohydrase enzymes speed up the process of altering the texture of the soybean due to enzymatic hydrolysis of the cell walls of the soybean. The enzymes are also capable of hydrolising a fraction of the oligosaccharides. A minimum level of chlorine (or another disinfecting agent) is also present in the water to prevent bacterial contamination during the germination process. The amount of enzymes added should be sufficient to convert 1 to 99% of the oligosaccharides stachyose and raffinate into hydrolysed products. In one embodiment, approximately 1.5kg of enzyme is used per ton of dry soybeans. During the initial sterilisation step, a chlorine concentration of between 200 and 250 ppm is maintained. During germination, a chlorine concentration of between 80 and 100 ppm is maintained.

The Ferris wheels are electronically programmed to rotate for approximately 48 hours, and the operating temperature of the water in the basins is maintained at between 25 to 30°C via Programmable Logic Controllers. This allows for the germination of the soybeans. After the germination process has been completed, the basins below the Ferris wheels are filled with rapidly boiling water and the cotyledons in the ladles are blanched for approximately 60 seconds per ladle. Thereafter the cotyledons are rapidly cooled with cold water which is circulated through the basins.

A sliding mechanism in the base of each ladle allows the germinated soybeans to be discharged from the ladles and conveyed to a screening arrangement 20 for dehulling. Dehulling the heat treated soybeans to recover the cotyledons at this stage is preferred, to ensure that the final product is ground down to a desirable particle size. However, dehulling at this stage is not imperative. If the legumes are not dehulled at this stage, hulls are removed as course material 42 in the classifier 40 described below. Dehulling can be effected by any of the known means, but in a preferred embodiment the cotyledons are dehulled by means of strong jets of water which strip the hulls from the cotyledons, and sizing screens 22 that allow the smaller hulls to be separated from the larger cotyledons. The dehulled cotyledons are subsequently dried, typically in four drum dryers 24 as shown in Figure 2, to a residual moisture content of 5%. The residual moisture content could be between 0 and 30% but is preferably between 4 and 7%. As part of the dehulling process, the hulls are also collected, dried and milled before being packaged and sold. The hypocotyls/roots are also collected for further processing.

Referring to Figure 1 , the dried cotyledons are milled in roller mills 26 (alternatively the dried cotyledons could be flaked) and then substantially all of the soybean oil present in the dried cotyledons is removed via a conventional solvent extraction step 28. Food grade, -industrial hexane 30 is the solvent used in the solvent extraction step process. However, other solvents which are capable of extracting lipids may also be used. The defatted material is separated from the solvent-oil solution (also known as "micella") by the use of screens. The hexane from the micella is recovered by evaporation 32 whereafter the soybean oil is refined 34 and stored 36 before it is sold.

The defatted material is then milled together with fresh hexane, in a colloid mill 38. Any other type of mill may be used. Other solvents, or a mixture of solvents, could be used instead of hexane. A classifier 40 is used to separate a heavier, coarser material 42 from the required fine particles 44. A typical fine particle size is between 10 and 50 microns but could be anywhere between 1 and 1000 microns. In the case where the hulls have already been removed, the coarser material is remilled to achieve this size. If the hulls have not yet been removed, the coarser material, containing the hulls, may be collected, packaged and sold. Finally, the solvent is removed by a process of evaporation. The solvent vapours are condensed separately. Any known form of solvent evaporation could be used, but flash evaporation via spray nozzles 46 onto a hot rotating drum 48 is particularly efficient. In a preferred embodiment the drum operates at a temperature of 120°C. The drying process takes approximately 1 to 2 seconds and the dry powder is removed from the surface of the drum by means of Teflon™ scrapers. The powder is stored under Nitrogen 50 until it is packaged 52 under the aseptic conditions. Any other inert gas, for example carbon dioxide, could be used instead of Nitrogen.

Example 1

100 Kg of mature, whole soybeans (containing between 35 to 40% protein and 18 to 19% oil) are loaded into a ladle (14) of the ferris wheel (12). 1000 Litres of water containing about 300-500 ppm of chlorine is pumped into a basin (18) located below the particular ferris wheel. The ladle is immersed in the water every 5 minutes for a period of 30 seconds. After 15 minutes the water in the ladle is drained and replaced with 1000 litres of fresh water at 25 ^°C. The ladle containing the beans is allowed to pass through the basin and be completely immersed every 4 to 6 hours over a period of 48 hours. A chlorine level of approx. 100-200 ppm is maintained in the water. The water in basin the (18) is replaced with boiling water and the beans in the ladle immersed for 1 minute, whereafter the temperature of the beans is lowered to below 65°C by immersing the ladle into cold water. The cooled blanched product is discharged from the ladle via a sliding mechanism in the base of the ladle and conveyed to a screening arrangement (20) for dehulling. The product is sprayed with water for 30 seconds to separate the hulls, germs and rootlets from the cotyledons on sizing screens (22). The cotyledons are dried in a drum dryer (24) at 60 °C for 24 hours to a final moisture content of 5%. The cotyledons are milled in a roller mill (26) for 3 minutes and subjected to conventional solvent extraction (28) using commercial hexane (30). The substantially defatted material is milled in a colloid mill (38) for 2 hours in 100 litres of fresh solvent, whereafter it is pumped to a classifier (40) to separate the fine and coarse particles. The colloidal material in the solvent is subjected to flash evaporation on a rotating drum (48) at 120 ^°C for 2 seconds to remove most/all of the hexane. The resulting soy protein powder, which has a particle size of from 10 to 60 microns contains between 50 to 65% protein and 0.5 to 1% oil, is stored under nitrogen (50).

Example 2

Typical apparatus used to best produce protein powder from legumes is shown in Figures 1 & 2. However, that any suitable apparatus that allows for the continuous or batch-wise germination and blanching, followed by solvent oil-extraction and classification, can be used.

100 Kg of mature, whole soybeans (containing 35 to 40% protein and 18 to 19% oil) are loaded into a ladle (14) of the ferris-wheel (12). 500 Litres of water containing about 300-500 ppm of chlorine is pumped into a basin (18) located below the particular ferris-wheel. The ladle is immersed in the water every 5 minutes for a period of 30 seconds. After 15 minutes the water in the ladle is drained and replaced with 500 litres of sodium phosphate buffer (pH 7.0) at 37 ^"C. To the buffer is added 0.5 kg β- galactosidase and 0.5 kg cellulase enzymes. The ladle containing the beans is allowed to pass through the basin and be completely immersed every hour over a period of 48 hours. A chlorine level of approx. 100-200 ppm is maintained in the water.. The buffer in the basin (18) is replaced with boiling water and the beans in the ladle are immersed for 1 minute, whereafter the temperature of the beans is lowered to below 65°C by immersing the ladle into cold water. The blanched product is discharged from the ladle via a sliding mechanism in the base of the ladle and conveyed to a screening arrangement (20) for dehulling. The product is sprayed with water for 30 seconds to separate the hulls, germs and rootlets from the cotyledons on sizing screens (22). The cotyledons are dried in a drum dryer (24) at 60 ^°C for 24 hours to a final moisture content of 5%. The cotyledons are milled in a roller mill (26) for 3 minutes and subjected to conventional solvent extraction (28) using commercial hexane (30). The substantially defatted material is milled in a colloid mill (38) for 2 hours in 100 litres of fresh solvent, whereafter it is pumped to a classifier (40) to separate the fine and coarse particles. The colloidal material in the solvent is subjected to flash evaporation on a rotating drum (48) at 120 "C for 2 seconds to remove most/all of the hexane. The resulting soy protein powder is stored under nitrogen (50). This powder usually has a particle size of from 10 to 60 microns, and contains between 50-65% protein and less than 1% oil.

Example 3

Typical apparatus used to best produce protein powder from legumes is shown in Figures 1 & 2. However, any suitable apparatus that allows for the continuous or batch-wise' germination and blanching, followed by solvent oil-extraction and classification, can be used.

100 Kg of mature, whole soybeans (containing between 35 to 40% protein and 18 to 19% oil) are loaded into a ladle (14) of the ferris-wheel (12). 500 Litres of water containing about 300-500 ppm of chlorine is pumped into a basin (18) located below the particular ferris-wheel. The ladle is immersed in the water every 5 minutes for a period of 30 seconds. After 15 minutes the water in the ladle is drained and replaced with 500 litres of fresh water at 25 ^°C. The ladle containing the beans is allowed to pass through the basin and be completely immersed every hours over a period of 48 hours. A chlorine level of approx. 100-200 ppm is maintained in the water. The product is discharged from the ladle via a sliding mechanism in the base of the ladle and conveyed to a screening arrangement (20) for dehulling. The product is sprayed with water for 30 seconds to separate the hulls, germs and rootlets from the cotyledons on sizing screens (22). The cotyledons are dried in a drum dryer (24) at 60 °C for 24 hours to a final moisture content of 5%. The cotyledons are milled in a roller mill (26) for 3 minutes and subjected to conventional solvent extraction (28) using commercial hexane (30). The substantially defatted material is milled in a colloid mill (38) for 2 hours in 100 litres of fresh solvent, whereafter it is pumped to a classifier (40) to separate the fine and coarse particles. The colloidal material in the solvent is subjected to flash evaporation on a rotating drum (48) at 120 °C for 2 seconds to remove most/all of the hexane. The resulting soy protein powder is stored under nitrogen (50). It usually has a particle size of from 10 to 60 microns and contains between 45-65% protein and is totally or partially enzyme active.

Claims

1. A method for producing a protein powder from legumes, the method including the steps of: germinating the legume to form a cotyledon, hull and root; optionally heat treating the germinated legume to inactivate at least some enzymes; drying the legume; grinding the dried legume; defatting the dried legume by means of solvent extraction which removes substantially all of the oil present in the dried legume; milling the defatted legume in excess solvent to a desired particle size; removing the solvent from the milled particles; and cooling the milled and desolventised particles.

2. A method according to claim 1, wherein the step of germinating the legume includes the step of submerging the legume in water, in a dark enclosure, for between 2 and 10 minutes, and at an operating temperature of between 0 and 60°C.

3. A method according to claim 2, wherein the step of germinating the legume includes the step of submerging the legume in water, in a dark enclosure, for 60 seconds and at an operating temperature of between 25 and 30°C.

4. A method according to any one of the preceding claims, wherein the step of germinating the legume includes the addition of an enzyme preparation for hastening hydrolysis of the cell walls of the legume during germination.

5. A method according to claim 4, wherein the enzyme preparation includes lysozyme, beta-glucosidase, beta-amylase, beta-glucanase or pectinase.

6. A method according to any one of the preceding claims, wherein the step of germinating the legume is carried out in the presence of an enzyme preparation capable of biochemically reducing the levels of oligosaccharide in the legume.

7. A method according to claim 6, wherein the enzyme preparation capable of biochemically reducing the levels of oligosaccharide in the legume includes stachyase, exoglycosidases, invertase, lactase or pectinase.

8. A method according to any one of the preceding claims, wherein the step of germinating the legume is carried out in the presence of an antibacterial agent.

9. A method according to any one of claims 4 to 8, wherein the step of germinating the legume is conducted over a period of 1 to 400 hours.

10. A method according to claim 9, wherein the step of germinating legume is conducted over a period of 48 to 96 hours.

11. A method according to any one of the preceding claims, which includes an initial step of disinfecting the legume with an antibacterial agent.

12. A method according to any one of the preceding claims, wherein the step of heat treating the germinated legume comprises the step of blanching the germinated legume with boiling water or steam for a period of between 1 second and 40 minutes.

13. A method according to claim 12, wherein the step of heat treating the germinated legume comprises the step blanching the germinated legume with water or steam for a period of 1 minute.

14. A method according to claim 12 or 13, wherein the step of heat treating the germinated legume comprises a further step of cooling the blanched legume to a temperature below 65°C.

15. A method according to any one of the preceding claims, wherein the step of drying the legume includes drying the legume to a residual moisture content of between 0 and 30%.

16. A method according to claim 15, wherein the step of drying the legume includes drying the legume to a residual moisture content of between and 4 and 7%.

17. A method according to any one of the preceding claims, wherein the step of defatting the dried legume comprises the further step of recovering and refining the oil. - .

18. A method according to any one of the preceding claims, wherein the method includes the step of dehulling the legume prior to the milling step.

19. A method according to claim 18, wherein the dehulling step takes place after the heat treatment step to recover the cotyledon which is then dried, ground, defatted and milled.

20. A method according to claim 18 or 19, wherein the step of dehulling the heat-treated legume also comprises the further step of recovering, drying and milling the hull and also the step of recovering the hypocotyls/roots.

21. A method according to any one of the preceding claims, wherein the step of milling the defatted legume includes classifying the milled particles and remilling the oversize particles to produce a particle size of between 1 and 1000 microns.

22. A method according to claim 21 , wherein the step of milling the defatted legume includes classifying the milled particles and remilling the oversized particles to produce a particle size of between 10 and 60 microns.

23. A method according to any one of the preceding claims, wherein the step of removing the solvent from the milled particles includes flash evaporation on a hot drum.

24. A method according to any one of the preceding claims, wherein the step of cooling the milled particles includes cooling to a temperature below approximately 65°C.

25. A method according to claim 24, wherein the step of cooling the milled particles occurs in the presence of an inert gas.

26. A method according to any one of the preceding claims, wherein the legumes are soybeans and the method is for producing a high- protein, substantially fat-free powder, with reduced oligosaccharide levels, from soybeans.