DE19907723A1 - Preparation of vegetable protein concentrates, especially soya protein concentrate, with improved protein contents and with production of animal feeds as by-products - Google Patents

Abstract

Vegetable protein concentrate is prepared by: (a) suspending ground starting material in an aqueous acid (pH 3-6) to give a mash; (b) maintaining the mash at the isoelectric point of the protein in the starting material, and (c) concentrating the mash residue. Prior to isoelectric treatment, an enzyme which cleaves carbohydrates is added for hydrolytic treatment at 30-60 deg C. Preparation of a vegetable protein concentrate from a starting material which contains a protein with an isoelectric point comprises: (a) grinding the starting material to a powder; (b) suspending the powder in an aqueous acid (pH 3-6) to give a mash; (c) maintaining the mash at the isoelectric point of the protein for isoelectric treatment; and (d) concentrating the residue of the mash. Prior to the isoelectric treatment of the mash, at least one enzyme which cleaves carbohydrates is added to the mash for a hydrolytic treatment at 30-60 deg C.

Description

The invention relates to a method of manufacture of a vegetable protein concentrate from a protein with an isoelectric point containing starting substance the preamble of claim 1.

In addition to protein flours, protein concentrates represent the indu The largest group of vegetable protein carriers. Compared to protein flours, protein concentrates are different about 20% higher protein content. This increased protein content is usually achieved by increasing the concentration soluble carbohydrates, minerals and fats as well as others Non-protein ingredients reduced by extraction processes will. The soluble fraction can also be so-called anti Contain nutritive accompanying substances, which can be found in higher concentrations tration can have a damaging effect on the organism when consumed can, for example: B. trypsin inhibitors, plant estrogens, isoflavones, and plant toxins.

Commercially important protein concentrates are made from soybeans won. From the soy flakes produced during the oil extraction the soluble components are removed, and the remaining Material is dried and then further processed. The drying of the soy flakes is essential for their suitability for that subsequent processing has so far been of crucial importance. Depending on the drying process, a distinction is made between toasted soy flakes and not toasted soy flakes (white soy flakes). By the Desolventizing toasting process (DT process), which is part of the Toasted soy flakes leads to the protein being so strong denatured that it was so far for further treatment is useless. Hence the toasted soy flakes used exclusively as animal feed. The gentler one and that Egg white is significantly less of a denaturing drying process the flash desolventizing process (FD process), which leads to the non-toasted soy flakes, however, clearly lead higher procedural costs. For the production of Protein concentrates made from soy flakes are currently only the not toasted soy flakes with a high protein solubility used, typically by a factor of three to four times higher than in the toasted soy flakes.

From "Technology of Production of Edible Flours and Protein Products form Soybeans" Berk, Z, FAO Agricultural Services Bulletin 97, FAO, (1992) three different processes are known for producing protein concentrates from non-toasted soy flakes. It is about

• a) to extract the soy flakes with alcohol and water,
• b) to extract the soy flakes with water at the iso electrical point of proteins and
• c) the heat denaturation of the soy flakes with subsequent aqueous extraction.

It has the extraction of the flakes with water at the Isoelek tric point of proteins (b) the characteristics of the generic term of claim 1. In all cases (a) to (c) will be Oligosaccaride, Raffynose and Stachyose and others not protein constituents of the soy flakes into the aqueous phase extracted. The resulting suspensions are usually separated into solids and solution with decanters or centrifuges and then neutralized and dried.

In addition to soy beans, other raw materials can also be used for the Used in the manufacture of vegetable protein concentrates will. Vegetables are particularly interesting from an economic point of view Raw materials that are initially used for oil production, which produces a protein-rich residue. This is what it is for example peanuts, rapeseed, sunflowers, sesame, Flaxseed, cotton and other oilseeds.

The invention has for its object to provide a method according to the To develop the preamble of claim 1 in such a way that a large-scale production of protein concentrates both from slightly denatured as well as from heavily denatured Flakes and flours can be used in oil production attack.

This object is achieved according to the invention by a method with the Features of claim 1 solved.

Advantageous embodiments of this method are shown in Subclaims 2 to 10 described.

When carrying out the method according to the invention, the Starting substance, d. H. usually flakes or meal, too a flour, which is preferably a medium particle size of 50 to 100 µm. Then the flour is in water using mineral acids and / or organic acids suspended. The temperature of the aqueous acid in this Process step is 30 to 60 ° C, preferably about 50 ° C. The mineral acid used can be, for example Act hydrochloric acid or sulfuric acid. The alternative or additional organic acid used can, for example Be acetic acid or citric acid. The dry matter content the resulting mash is typically 12 to 20%. A preferred dry matter content is 17%. The pH The value that is set for the mash is on that Activity maximum of the sum of in a next step the carbohydrate-splitting enzymes used between 3 and 6, especially at 5. That after preparation Charcoal added to the mash and pH adjustment hydrate-splitting enzyme for hydrolytic treatment of the Mash can be a single enzyme. Preferably it acts but it is a mixture of enzymes that is used on the Starting material and the desired protein concentrate is to be agreed. Enzymes from the are particularly suitable the following enzyme classes (EC): 3.1.1.1, 3.1.1.11, 3.1.1.12, 3.1.1.3, 3.2.1.1, 3.2.1.2, 3.2.1.3, 3.2.1.4, 3.2.1.6, 3.2.1.11, 3.2.1.15, 3.2.1.20, 3.2.1.21, 3.2.1.22, 3.2.1.23, 3.2.1.25, 3.2.1.26, 3.2.1.32, 3.2.1.37, 3.2.1.39, 3.2.1.41, 3.2.1.55, 3.2.1.58, 3.2.1.6, 3.2.1.67, 3.2.1.71, 3.2.1.72, 3.2.1.73, 3.2.1.74, 3.2.1.75, 3.2.1.77, 3.2.1.78, 3.2.1.80, 3.2.1.82, 3.2.1.88, 3.2.1.89, 3.2.1.90, 3.2.1.91, 4.2.2.2, 4.2.2.6, 4.2.2.9 and 4.2.2.10.

These enzymes work for a period of 15 to 45 minutes. preferably from about 30 minutes at the set pH the carbohydrate / fat matrix of the suspended flour. The pH Meanwhile, value does not have to be recorded, but represents preferably under the action of the enzymes themselves. After the enzymes have had their effect, the pH will increase to a mineral or organic acid, which is is preferably the same acid with which he was previously the pH of the mash was adjusted to the isoelectric Set point of protein contained in the mash, and the mash is stirred at the isoelectric point, preferably for about 15 min. Then the isoelectric point resulting residue of the mash, for example by filtration or centrifugation concentrated. The filtrate contains the Impurities and the anti-nutritional substances, the residue the protein in concentrated form. Then the Pro tein suspended again with warm water and then be concentrated again to do a wash.

In this way, starting substances also become strong denatured protein a high quality protein concentrate obtain.

If a further increase in the protein solubility in the protein concentrate is desired, it is possible, after hydrolytic treatment of the mash with the carbohydrate-splitting enzyme, which acts on the impurities in the form of carbohydrates and fats, followed by protein hydrolysis by means of proteases. It makes sense to concentrate the residue of the mash after the hydrolytic treatment first at the isoelectric point and then to suspend the residue with water at approx. 50 ° C. A further washing of the residue with water can also be interposed. Then the pH is increased by means of a hydroxide so that the pH reaches the maximum activity of the protease to be used. This corresponds to a pH range from 4.5 to 10, in particular from 7 to 9. The hydroxide can be NaOH, KOH, Ca (OH) ₂ or the like. Suitable proteases are: serine proteases, cysteine proteases, aspartic acid proteases and / or metal proteinases. After adding the protease, the suspension is stirred until the protein solubility is desired. There should be no pH correction of the suspension, so that the pH value preferably falls below pH 7.

To inactivate the proteases used to prevent germs of protein concentrate and / or removal of steam-volatile flavors can be improved the concentrated residue of the mash from a heat treatment be subjected. So the temperature of the residue can get through Steam injection for 10 to 120 seconds, especially about 90 seconds 80 to 180 ° C, preferably to 80 to 130 ° C and in particular be kept at approx. 110 ° C.

For pre-drying or just for flashing off the concentrate trated residue of the mash can turn the residue into a sprayed under vacuum centrifugal separator will. The pressure in a product line upstream of the centri The fugal separator is adjusted to 1 to 6 bar for this purpose. Under This pressure is the concentrated residue of the mash via an introduction to the Cylinder of the centrifugal separator shot in or relaxed, so that the cross section of the suspension by one Broadened by a factor of 10. In the cylinder of the centrifugal There is a vacuum in the separator. This vacuum should be possible be great. A vacuum of less than 250 mbar is technically achievable, in particular from approx. 200 mbar. The one in the cylinder of the Centrifugal separator entering residue of the mash forms a film that prevents outgassing of steam or air made possible quickly and without the formation of foam. On the cylindrical circular path of the residue of the mash in the This effect is compounded by the centrifugal separator Centrifugal effect supported. The vapors or gases escape into the cylinder interior, which is under vacuum. In addition to the Outgassing also takes place as a water evaporation that removes the residue the mash cools down, the cooling effect from the pressure gradient within the cylinder is dependent. The steam or the escaped gases are in a known manner via the upper Cylinder part sucked off and then condensed. Down from the centrifugal separator is the pre-dried or evaporated or just degassed residue of the mash deducted. This type of pre-drying or flashing can both before and after an additional wash of the Residue of the mash to be carried out.

For starting substances in which even larger amounts of oil is included, the additional use of surfactants has during the hydrolytic treatment of the mash with the carbohydrate-splitting enzyme proven to be beneficial. As a surfactant is For example, sodium dodecyl sulphate (SDS) can be used, which is used in a concentration of 0.05 to 0.1% based on the Starting material is sufficient to remove residual fats and oils emulsify. The protein solubility in the protein concentrate is increased not increased by this. Alternatively or in addition to Surfactants can also act as extraction aids for in the lipases Oils and fats contained in the starting substance can be used.

If the starting substance contains impurities, those only with polar organic solvents like alcohols can be extracted, it makes sense to remove these impurities after the hydrolytic treatment of the mash with the carbohydrate-splitting enzyme extract by the mash Alcohol, especially ethanol, is added and the Mash only then the isoelectric treatment on the iso subjected to electrical point of the protein for about 15 min will. The alcohol concentration should be 5 to 20% by volume, in particular 8% by volume can be set. The next steps to obtain the protein concentrate can then without Modification run.

It goes without saying that after concentrating and before Drying of the residue of the mash nor its pH value to the desired pH of the end product must be adjusted. For this purpose, acids and alkalis can be used in a known manner will. Those that may arise when adjusting the pH Salts can be added to the concentrated residue if necessary be withdrawn.

Surprisingly, it turns out that the enzymatic Cleavage of the non-protein components of the starting substance essential properties of the protein concentrate obtained certainly. The properties of the protein concentrate obtained are those of the native acid precipitated proteins comparable. That is, the protein concentrate obtained in this way Has functional properties that are also found in proteins in non-toasted flakes in water binding, emulsifying self Shank, solubility and sensory properties are superior, even if as Raw material toasted flakes can be used.

The enzymatic digestion of the starting substance also leads to that the impurities contained in the starting material, such as fats, sapolines, isoflavones and other accompanying substances (e.g. Pesticides) more easily in the later separated pass liquid phase and thus to a higher proportion removed. Furthermore, the fiber and carbohydrate matrix the original substance split up in such a way that a new orientation the proteins is induced. That is, the proteins will restructured. The subsequent separation of the mash in soluble fibers and solids results in a highly pure protein concentrate with low protein losses in the liquid phase.

With the new process, 25% the solids of the starting substance separated, in which about 5% of the protein originally present. In one any second washing step will be without any noteworthy further Protein losses an additional 8 to 10% non-protein solids removed. This creates a protein concentrate with a Protein content of 75 to 85% based on the solids content (TS). In the previously known method for obtaining Protein concentrates were protein concentrates with protein contents gained from only 65 to almost 75%. Here is the protein concentrate as the end product of the new process sensory comparable to a protein concentrate that is exclusively made with Ethanol and water was extracted.

The soluble filtrate separated from the residue of the mash can be evaporated or filtered. One falls high-energy substance that is used as animal feed can. Filtration can also provide high quality fermentation aid (C source) for various biological processes or a Carbohydrate source for beverages are generated. So can with that The wastewater stream is also used commercially with new processes will.

The invention is explained in more detail below with the aid of examples explained and described.

example 1 Protein concentrate from toasted soy meal

Heat-treated, toasted soy meal is produced in soybean oil production. This meal has a water content of 10 to 12%, a protein content of 48% and a content of other substances of 40%. These other substances mainly consist of soluble and insoluble carbohydrates. Such a soy meal is ground to a soy flour which has a particle size of 50 to 100 μm. With an even finer flour, the extractability would be further increased, but such fine particles would no longer be able to be separated using a decanter. The flour with a particle size of 50 to 100 μm is mixed with water at 52 °, to which hydrochloric acid is added, in a ratio of 1: 6. During this mixing process, care is taken to keep the pH value at 5 by constantly adding acid. After the end of the mixing process, the mash created by the suspension of the flour has a dry matter content of 15%. The temperature of the mash is 50 ° C. The mash becomes a liquid enzyme mixture of EC 3.1.1.11, EC 3.2.1.1, EC 3.2.1.15, EC 3.2.1.32, EC 3.2.1.4, EC 3.2.1.55, EC 3.2.1.72, EC 3.2.1.78 and EC 4.2. 2.10 added so that the amount of enzyme is 0.8% based on the weight of the suspended flour. This amount used has proven to be a suitable specification for various enzymes from different manufacturers. It can be optimized for the individual case. After adding the enzymes, the mash is continuously and intensively mixed. After thirty minutes of thorough mixing, the pH is adjusted to 4.2 to 4.6, in particular 4.3, with hydrochloric acid, and stirring is then continued for 15 minutes. This corresponds to an isoelectric treatment of the proteins contained in the soy meal. After a total of 45 minutes after adding the enzymes, the mash is separated using a decanter (at 4500 × g). The centrate (filtrate) contains the dissolved substances, the solids discharge (residue) the protein fraction. The centrate has a solids concentration of 8 to 8.5%, the solids discharge from 32 to 33%. The residue is suspended again in warm water at 50 ° C. and decanted one more time. Then water is added to the solids discharge until a solids content of 16% (TS) is reached. This suspension is pasteurized by heat treatment and then neutralized to pH 6.2 with 25% sodium hydroxide solution. This material then has a solids content of 15% (TS) and is spray-dried. The protein concentrate obtained in this way has the following composition:

water 7% protein 76% ash 4.5% fat <0.1% Carbohydrates / fibers 12.5%

and has a neutral taste.

Example 2 Protein concentrate from rapeseed meal

Heat-treated rapeseed meal is produced during the production of rapeseed oil normally used as animal feed. This Rapeseed meal has a water content of 10 to 12%, a Protein content of 42% and a content of other substances of 48%, consisting essentially of soluble and insoluble Carbohydrates. Such a meal turns into a flour ground, which has a particle size of 50 to 100 microns. This flour is made with 52 ° hot water, the hydrochloric acid and 0.75 Weight percent sodium dodecyl sulphate (SDS) based on the Weight of flour added, mixed in a ratio of 1: 6. When making a mash in this way, it is important to ensure that the pH value is kept at 5 by constant addition of acid. To At the end of the mixing process, the mash is dry substance content of 15%; the resulting temperature is 50 ° C. This mash becomes a liquid enzyme mixture from EC 3.1.1.11, EC 3.1.1.3, EC 3.2.1.1, EC 3.2.1.15, EC 3.2.1.21, EC 3.2.1.32, EC 3.2.1.4, EC 3.2.1.6, EC 3.2.1.72, EC 3.2.1.78 and EC 4.2.2.10 were added in such a way that based on the Weight of the suspended flour the amount of enzyme 1 percent by weight amounts to. The mash is then mixed with the enzyme for Thoroughly mixed for 30 minutes. After the 30 min the pH will be with hydrochloric acid to the isoelectric point of pH 4.3 set and there is stirred for a further 15 min. After 45 min since the use of the enzyme mixture, the mash has become over separated a decanter (at 4500 × g). The centrate contains the Substances dissolved from the starting substance, the solids discharge the protein fraction. The centrate has a solid concentration tion of 7.5 to 8%, the solids discharge from 30 to 33%. This residue of the mash is again with 50 ° C warm water suspended and subjected to a heat treatment by direct steam injection sterilized at 100 ° C within 120 seconds. Afterward the hot suspension is flashed under vacuum, d. H. evaporated, cooled to 50 ° C and again over a decanter centrifuged. The solids discharge from this decanter is resuspended with water and then with 25% Sodium hydroxide solution neutralized to pH 6.2. This material then becomes spray dried.

The protein concentrate obtained in this way has the following composition:

water 7% protein 75% ash 4.2% fat <0.2% Carbohydrates / fibers 13%

and a neutral taste.

Claims (10)

1. Process for the production of a vegetable protein concentrate from a starting substance containing proteins with an isoelectric point:

• - whereby the starting substance is ground to a flour,
• - the flour being suspended in an aqueous acid to form a mash with a pH of 3 to 6,
• - the mash being held at the isoelectric point of the protein for an isoelectric treatment, and
• - whereby a residue of the mash is concentrated,

characterized in that at least one carbohydrate-splitting enzyme for hydrolytic treatment at a temperature of 30 to 60 ° C is added to the mash prior to its isoelectric treatment. 2. The method according to claim 1, characterized in that the Starting substance for a flour with an average particle size is ground from 50 to 100 µm. 3. The method according to claim 1 or 2, characterized in that that the mash for their hydrolytic treatment next to that at least one carbohydrate-splitting enzyme at least one Protease is added. 4. The method according to any one of claims 1 to 3, characterized that draws the mash for its hydrolytic treatment in addition to the at least one carbohydrate-splitting enzyme at least one lipase is added. 5. The method according to any one of claims 1 to 4, characterized that draws the mash for its hydrolytic treatment in addition to the at least one carbohydrate-splitting enzyme at least one surfactant is added. 6. The method according to any one of claims 1 to 5, characterized shows that the residue of the mash after the concentration ren is washed with water and concentrated again. 7. The method according to any one of claims 1 to 6, characterized draws that the residue of the mash with an aqueous Alcohol solution is extracted. 8. The method according to any one of claims 1 to 7, characterized records that the residue of the mash by centrifugation, Filtration or decanting is concentrated. 9. The method according to any one of claims 1 to 8, characterized draws that the residue of the mash for a heat treatment is heated to 80 to 130 ° C for 30 to 120 s. 10. The method according to any one of claims 1 to 9, characterized draws that the concentrated residue of the mash for Predrying, for evaporation and / or for outgassing in one centrifugal separator under vacuum will.