IE45808B1

IE45808B1 - Improvements in or relating to edible oilseed extracts

Info

Publication number: IE45808B1
Application number: IE2126/77A
Authority: IE
Original assignee: Taylor P Co Inc
Priority date: 1976-11-26
Filing date: 1977-10-18
Publication date: 1982-12-01
Also published as: GB1570746A; IE45808L; JPS5369845A

Description

This invention is an improvement in or modification of the invention of Patent’ Specification No. 43623 to which reference may be made.

It is an object of the invention to provide a process for producing an improved edible extract from oilseeds, preferably whole soy beans of whole peanuts.

We have found'1 inter alia that advantageously one part by weight oilseed is comminuted in the presence of from 3 to 15 parts by weight of a hot alkaline extraction solution with a pH of more than 11 and a temperature of at least 180°F to yield an alkaline comminuted oilseed/extraction solution mixture having e.g. a pH of at least 8. Preferably the extraction solution comprises sodium hydroxide, and the temperature of the extraction solution is near boiling, e.g. 2O5°F. After comminution the oilseed is soaked in the extraction solution ftor from 1 to 20 minutes, and preferably from 3 to 7 minutes with the object of extracting protein, carbohydrates and liquids from the seed material. After the extraction step, the comminuted oilseed/ extraction solution mixture is neutralized with an acidic solution, which preferably comprises hydrochloric acid, and clarified e.g. by centrifuging to yield an essentially clear extract and a sludge.

The invention provides a process for preparing a stabilized, full fat, high protein edible extract from an oilseed comprising the steps of: (a) comminuting one part by weight full fat oilseed in the presence of from 3 to 15 parts by weight of a hot - 3 alkaline extraction solution with a temperature of at least 180°F and a sufficiently high pH of more than 11 so that the comminuted oilseed/extraction solution mixture is alkaline; (b) soaking the comminuted oilseed in the extraction solution for from 1 to 20 minutes; and (c) neutralizing with an acidic solution and clarifying the comminuted oilseed/extraction solution mixture to yield an essentially clear extract and a sludge.

The pH of the extraction solution is for example not greater than 13, but in a modification this pH is at least 13.

The pH qf the comminuted oilseed/extraction solution mixture is for example not greater than 11.

Preferably the extraction solution temperature is at least 2O5°F.

Although we believe the bulk of the antinutritional factors in the oilseed is destroyed during the comminution and extraction steps, the clear extract is further treated if necessary by the additional step of heating the extract to a sufficient temperature for a sufficient time, such as to 285°F for 15 seconds, to further « i destroy any anti-nutritional factors such as anti-trypsin in the extract.

If a powder product is desired, the extract can be concentrated and spray dried using knowing means to yield a stabilized, full fat, high protein powder. This powder can be instantized using known means to improve the powder's dispersibility in aqueous solutions.

The invention also provides a process for preparing a stabilized, full fat, high protein, edible powder from whole soy beans comprising the steps of (a) comminuting in a hammermill one part by weight full fat soy bean in the presence of 3 to 15 parts by weight of a hot alkaline extraction solution - 4 which comprises sodium hydroxide and has a temperature of at least 2O5°F and a sufficiently high pH from more than 11 and up to 13 that the comminuted soy bean/extraction solution mixture is alkaline; (b) extracting protein, carbohydrates, and lipids from the soy beans by soaking the comminuted soy beans in the extraction solution for from 3 to 7 minutes; (c) neutralizing the comminuted soy bean / extraction solution mixture with an acidic solution comprising hydrochloric acid; (d) centrifuging the neutralized comminuted soy bean / extraction solution mixture to yield an essentially clear extract; (e) maintaining the clear extract at 285°F for 15 seconds to destroy any anti-nutritional factors; and (f) concentrating and spray drying the extract to yield the stabilized powder.

The invention also provides the product of a process according to the invention.

The product is for example a water dispersible food product, which when soy beans are the feed oilseed, contains from 15 to 30% by weight lipids and from 35 to 55% by weight proteins, where at least half and preferably at least 75% of the lipids are in the bound form (as hereinafter defined). Nearly all of the soluble portion of the soy bean is recovered, with essentially only the fiber being discarded.

Improved yield may be achieved by extracting with water residual food values which may be in the sludge.

There now fdllows a description, to be read with reference to the accompanying drawing, of a process embodying the invention. This description, which is also illustrative of product aspects of the invention, is given by way of example only, and not by way of limitation of the invention.

In the accompanying drawing the single figure shows a flow diagram of the process embodying the invention.

Referring to the drawing, an oilseed is comminuted in a comminution stage 10 in the presence of an extraction solution.

After comminution, the oilseed is soaked in the extraction solution in an extraction stage 12 and then the comminuted oilseed/extraction solution mixture is neutralized with an acidic solution. After clarification in a clarification stage 14, the extract is heated in a heating stage 16 to destroy any antinutritional factors and then cooled in a cooling stage 18. To produce a dispersible powder product, the extract from the cooling stage 18 is sent to a concentration stage 20, followed by a spray drying stage 22, and then an instantizing stage 24.

Examples of comminution processes which may be used include chopping, crushing, tearing, shredding, emulsifying and grinding by suitable machinery.

As used herein, the expression oilseed refers to a seed cultivated primarily for its oil content and which also contains a protein dispersible after comminution in an alkaline solution, and the term includes, but is not limited to, soy beans, peanuts, sesame seeds, cotton seeds, and safflower seeds. This process can be used with dehulled soy beans or deskinned peanuts, with or without presoaking. This process also can be used with whole soy beans and whole peanuts which have not been dehulled or presoaked, thereby eliminating the cost of presoaking or dehulling associated with other processes. Also, this process is useful for blends of oilseeds. For example, a blend containing soy beans and peanuts can be treated with this process.

It is preferred that the oilseed be cleaned prior to comminution to remove dirt, insects and other debris. This cleaning can be accomplished by an air stream.

The extraction solution serves to extract carbohydrates. 4S808 proteins and lipids, also known as fats, from the oilseed.

Sufficient extraction solution having a sufficiently high pH from more than 11 and up to 13 to yield an alkaline oilseed/ extraction solution mixture, i.e. a mixture having a pH greater than 7.0, is provided. The oilseed/extraction solution mixture generally has alower pH than the extraction solution by itself. Generally, the higher the pH of the extraction solution and thus the oilseed/extraction solution mixture, the higher the yields obtained from t}ie oilseed. For example, the yield increases from 61% to 85% as the pH of the oilseed/extraction solution I mixture is increased from 7 to 11 when soy beans are used as the oilseed feed. However, at a pH of 11 of the oilseed/extraction solution mixture, the resultant product has a slight sulfide / odor. Thus, the extraction solution is preferably limited to having a pH up to 13.

Preferably the extraction solution has a sufficiently high pH to yield an oilseed/extraction solution mixture having a pH from 8 to 10, and more preferably from 8.5 to 9. The resultant product is free of any substantial sulfide odor.

The temperature of the extraction solution is at least 180°F, and preferably near boiling, i.e. about 2O5°F. Temperatures near boiling serve to destroy the lipoxidase and other heat liable anti-nutritional factors in the oilseed and also drive off volatile components responsible for the beany flavor of soy beans.

From 3 to 15 parts by weight of the hot alkaline extraction solution per part oilseed are used. If less than about 3 parts are used it is found that the resulting slurry may be too viscous to handle conveniently when soy beans are used as the feed. At ratios greater than energy requirements may become prohibitively expensive in concentrating and spray drying the 3 8 0 8 extract. In addition high levels of extraction solution decrease the yield of the process because oilseed extracts tend to be discarded with the sludge produced in the clarifying stage.

To alkalize the extraction solution a nontoxic chemical which does not irreversibly react with the proteins, carbohydrates, or lipids in the source oilseed is employed. Such materials include sodium and potassium hydroxide, and sodium and potassium carbonate. The preferred chemical is sodium hydroxide because it is inexpensive and readily available.

It is desirable to comminute the oilseed to as fine a particle size as possible. The finer the grind of the material the larger the surface area available for extraction and thus the higher the yield of product. The preferred machinery for comminution is a hammermill, which has been shown to satisfactorily produce a fine grind of oilseed in the presence of the extraction solution. An added advantage cf a hammermill is that it tends to aerate the extraction solution. Since the extraction solution is at a high temperature, components of soy beans which tend to give a beany flavor are vaporized and driven off during the comminution operation, thereby reducing the beany flavor of the final product.

The comminution can occur under atmospheric pressure, or in the presence of a vacuum to withdraw the volatile components responsible for the beany flavor of soy bean products. Alternatively, the comminution can be done under pressure followed by venting or release undesirable flavors and odors. Comminution under pressure has the advantage of increasing the boiling point of the extraction solution, thereby permitting more severe treatment during the comminution step. 43808 - 8 ί λ < After comminution, the oilseed is soaked in the extraction solution in the extraction stage 12 for from 1 to 20 minutes, and preferably 3 tp 7 minutes . The purposes of the soaking are to maximize the amount of the nutritional elements extracted from the oilseed feed,' to destroy anti-nutritional factors such as anti-trypsin in the seed material, and to destroy lipoxidase.

If soaking times less than 1 minute are used, the yield tends to decrease and there may be inadequate destruction of the lipoxidase. If soaking times greater than 20 minutes are used the product tends to develop an off flavor from hydrolysis of the lipids. Also, higher soaking times require increased capital for larger volume soaking equipment.

The comminuted oilseed/extraction solution mixture is then neutralized with an acidic solution. A non-toxic acid is used, and it is preferred to use hydrochloric acid, since it is readily available and inexpensive. The acid solution should be thoroughly mixed with the mixture to prevent insolubilization of protein.

The rest of the process comprises steps for concentrating and stabilizing the extracted carbohydrates, lipids and proteins in the extraction solution. This involves clarifying the neutralized comminuted oilseed/extraction solution mixture in the clarification stage 14. clarification can be done before neutralization. A centrifuge is useful for accomplishing the clarification step. Sludge, which consists primarily of the fibrous component of the oilseed is the by-product of the clarification· step. However, there are residual extractible lipids, proteins and carbohydrates in the sludge. Therefore the yield of the overall process can be improved by recycling a portion of the sludge to the comminution stage 10 or, as shown in the drawing, to the extraction stage 12 for further extraction.

Alternatively, the sludge can be further extracted in one or more recycle stages where each stage includes the steps of soaking the sludge in water and then clarifying the sludge/water mixture.

The clear extract from the clarification stage 14 is fed to the heating stage 16 to destroy any anti-nutritional factors which were not* destroyed by the extraction solution, but this step may not be required for all types of oilseeds. In the heating step the clear extract is maintained at a sufficiently high temperature for a sufficient time to destroy anti-nutritional factors. Generally the higher the temperature used, the less residence time required in the heating stage. For example, the extract can be maintained at 285°F for 15 seconds in the heating stage to destroy anti-nutritional factors.

The extract is then cooled in the cooling stage 18 to minimize the risk degradation of the seed material extracts.

The clear extract can be used directly as product, either alone, or mixed with other liquid sources of nutrients such as whey.

If a product in a powder form is desired, the clear extract from the cooling stage 18 can be sent to the concentration stage 20 and the spray drying stage 22. When the powder is intended to be used with liquids, it can be instantized in the ihstantizing stage 24.

The above described can be conducted continuously for economies of operation.

The resultant high protein product powders appears to exhibit high stability with minimal rancidity and minimal flavor development in storage. It is essentially free of fiber and beany flavor. It is dispersible in water and compatible with 8 0 8 - 10 whey and other food materials. When combined with products such as whey, a powder made from soy beans yields a palatable, nutritious milk beverage.

When soy beans are used for feed the final product may 5 contain from 15 to 30% by weight lipids, and from 35 to 55% by weight proteins, where at least half of the lipids are in the bound form. As used herein the term bound lipids and lipids in the bound form refer to the percentage of the total lipids in the product which are not extracted by conventional petroleum ’ ether methods. Total lipids are determined by acid hydrolyzing the product before conducting the conventional ether extraction.

We believe the fact that the product of this process has high stability during storage is surprising in light of the commonly held belief that exposing lipids to a hot alkaline solution results in saponification of the lipids. Although not bound by theory we believe that the high stability of the product is due to the high percentage of bound lipids. It appears that the fat particles are encapsulated by a protein derivative during high speed comminution in the presence of the high temperature, high pH extraction solution. It seems that the alkali, rather than hydrolyzing the fat, reacts preferentially with the protein and, in effect, produces a protective colloid for the fat. This could be described as an enrobing or an encapsulating effect.

Claims

1. CIAIMS:1. A process for preparing a stabilized, full fat, high protein edible extract from an oilseed comprising the steps of: (a) comminuting one part by weight full fat oilseed in the presence of from 3 to 15 parts by weight of a hot alkaline extraction solution with a temperature of at least 180°F and a sufficiently high pH of more than 11 so that the comminuted oilseed/extraction solution mixture is alkaline; (b) soaking the comminuted oilseed in the extraction solution for from 1 to 20 minutes; and (c) neutralizing with an acidic solution and clarifying the comminuted oilseed/extraction solution mixture to yield an essentially clear extract and a sludge.

2. A process according to claim 1, wherein the pH of the extraction solution is not greater than 13.

3. A process according to claim 1, wherein the pH of the extraction solution is at least 13.

4. A process according to any one of claims 1, 2 and 3 wherein the pH of the comminuted oilseed/extraction solution mixture is not greater than 11.

5. A process according to any one of the preceding claims comprising the step of heating the clear extract to a sufficient temperature to destroy any anti-nutritional factors.

6. A process according to any one of Claims 1 to 4, comprising the step of heating the clear extract to 285°F to destroy any anti-nutritional factors.

7. A process according to Claim 6, wherein the extract is maintained at 2B5°F for 15 seconds.

8. A process according to any one of the preceding Claims, comprising the steps of concentrating and spray drying the clear extract to yield a dry powder. - 12

9. A process according to Claim 8, comprising the step of instantizing the powder.

10. A process according to any one of the preceding Claims, wherein the neutralization occurs prior to the clarification. 5

11. A process according to any one of the preceding Claims, wherein the oilseed is soy beans.

12. A process according to Claim 11, comprising the step of dehulling the soy beans before comminuting.

13. A process according to any one of the preceding Claims, 10 wherein the extraction solution comprises sodium hydroxide.

14. A process' according to any one of the preceding Claims, whereip a Jiammermill is utilized for comminuting the oilseeds. 1 \

15. A prooess according to any one of the preceding 15 Claims, wherein the extraction solution temperature is at least 2O5°F.

16. A process according to any one of the preceding Claims, wherein the comminuted oilseed/extraction solution mixture has a pH from 8 to 10. 20

17. A process according to any one of Claims 1 to 15, wherein the comminuted oilseed/extraction solution mixture has a pH from 8.5 to 9.

18. A process according to any one of the preceding Claims, wherein the comminuted oilseed is soaked in the extrac25 tion solution for from 3 to 7 minutes.

19. A process according to any one of the preceding Claims, v/herein the acidic solution comprises hydrochloric acid.

20. A process according to any one of the preceding Claims, wherein the clarifying step comprises centrifuging. 4S8GS - 13

21. A process according to any one of the preceding Claims, wherein the sludge is extracted in at least one recycle stage which comprises (a) soaking the sludge in water? and (b) clarifying the sludge/water mixture.

22. A process for preparing a stabilized, full fat, high protein, edible powder from whole soy beans comprising the steps of: (a) comminuting in a hammermill one part by weight full fat soy bean in the presence of 3 to 15 parts by weight of a hot alkaline extraction solution which comprises sodium hydroxide and has a temperature of at least 2O5°F and a sufficiently high pH from more than 11 and up to 13 that the comminuted soy bean/ extraction solution mixture is alkaline; (b) extracting protein, carbohydrates, aid lipids from the soy beans by soaking the comminuted soy beans in the extraction solution for from 3 to 7 minutes; (c) neutralizing the comminuted soy bean/extraction solution mixture with an acidic solution comprising hydrochloric acid; (d) centrifuging the neutralized comminuted soy bean/extraction solution mixture to yield an essentially clear extract; (e) o maintaining the clear extract at 285 F for 15 seconds to destroy any anti-nutritional factors; and (f) concentrating and spray drying the extract to yield the stabilized powder.

23. A process according to claim 22 wherein the pH of the comminuted oilseed/extraction solution mixture is up to 11.

24. A process according to claim 1 for preparing a high protein edible product substantially as hereinbefore described with reference to the accompanying drawings.

25. The product of a process according to any one of the preceding claims.

26. A water dispersible food product derived from whole soy beans and comprising lipids and proteins, wherein at least - 14 75% by weight of the lipids are in the bound form and prepared by a process according to claim 8.