Enzymatic process to produce highly functional soy protein from crude soy material
View Patent ↗This invention relates generally to the processing of soy-derived materials for use in various products. More particularly, the invention relates to a process producing highly functional soy protein using ultrafiltration followed by an enzymatic treatment.
1. A method for preparing highly functional soy proteins, said method comprising
(1) preparing a basic aqueous mixture of a soy material containing soy proteins, the basic aqueous mixture having a pH of about 8 to about 10;
(2) optionally removing insoluble materials from the basic aqueous mixture;
(3) passing the basic aqueous mixture through an ultrafiltration membrane having a molecular weight cutoff in the range of about 1,000 to about 50,000 Daltons while maintaining the pH of the basic aqueous solution at about 8 to about 10 during ultrafiltration, thereby removing soluble carbohydrates and low molecular weight materials;
(4) adjusting the pH of the basic aqueous mixture to a level sufficient to allow an enzyme or mixture of enzymes having endoprotease and exopeptidase activities to solubilize the soy proteins;
(5) solubilizing the soy proteins by treating the pH-adjusted aqueous mixture with the enzyme or mixture of enzymes having endoprotease and exopeptidase activities for a time sufficient to form the highly functional soy proteins;
(6) inactivating the enzyme or mixture of enzymes; and
(7) recovering the highly functional soy proteins.
2. The method of claim 1 , wherein the soy material is a crude soy material.
3. The method of claim 2 , wherein the crude soy material is defatted soy flour or oil-extracted soy meal.
4. The method of claim 1 , wherein insoluble materials are removed from the basic aqueous mixture prior to passage through the ultrafiltration membrane.
5. The method of claim 1 , wherein the pH of the basic aqueous mixture prior to passage through the ultrafiltration membrane is about 9 to about 10.
6. The method of claim 1 , wherein the pH of the basic aqueous mixture in step (4) is adjusted to about 6.8 to about 8.
7. The method of claim 1 , wherein the enzyme or mixture of enzymes is present in step (5) at about 0.05 to about 2 percent.
8. The method claim 1 , wherein the enzyme or mixture of enzymes is present in step (5) at about 0.25 to about 1 percent.
9. The method of claim 7 , wherein step (5) is carried out at a temperature of about 75 to about 140° F. and has a duration of about 0.5 to about 5 hours.
10. The method of claim 8 , wherein step (5) is carried out at a temperature of about 120 to about 125° F. and has a duration of about 1 to about 3 hours.
11. The method of claim 1 , wherein the recovered the highly functional soy proteins are separated into a soluble fraction and an insoluble fraction.
12. A method for preparing highly functional soy proteins, said method comprising
(1) heating a basic aqueous mixture of a soy material containing soy proteins to a temperature of about 100 to about 130° F., wherein the basic aqueous mixture has a pH of about 8 to about 10;
(2) removing insoluble materials from the basic aqueous mixture;
(3) passing the basic aqueous mixture through an ultrafiltration membrane having a molecular weight cutoff in the range of about 1,000 to about 50,000 Daltons while maintaining the pH at about 8 to about 10, thereby removing soluble carbohydrates and low molecular weight material;
(4) adjusting the pH of the basic aqueous mixture to about 6 to about 8;
(5) solubilizing the soy proteins by treating the pH-adjusted aqueous mixture with an enzyme or mixture of enzymes having endoprotease and exopeptidase activities at about 75 to about 140° F. for a time sufficient to form the highly functional soy proteins;
(6) inactivating the enzyme at about 160 to about 200° F.; and
(7) recovering the highly functional soy proteins.
13. The method of claim 12 , wherein the soy material is a crude soy material.
14. The method of claim 13 , wherein the crude soy material is defatted soy flour or oil-extracted soy meal.
15. The method of claim 12 , wherein the pH of the basic aqueous mixture prior to passage through the ultrafiltration membrane is about 9 to about 10 and wherein the pH of the basic aqueous mixture is maintained at about 9 to about 9.8 during ultrafiltration.
16. The method of claim 12 , wherein the enzyme or mixture of enzymes is present in step (5) at about 0.05 to about 2 percent and wherein step (5) is carried out at a temperature of about 100 to about 130° F. and has a duration of about 0.5 to about 5 hours.
17. The method claim 12 , wherein the enzyme or mixture of enzymes is present in step (5) at about 0.25 to about 1 percent and wherein step (5) is carried out at a temperature of about 100 to about 130° F. and has a duration of about 0.5 to about 5 hours.
18. The method of claim 12 , wherein the recovered the highly functional soy proteins are separated into a soluble fraction and an insoluble fraction.