Cereal Chem 47:72 - 78.  |  VIEW ARTICLE
Solubilization and Recovery of Protein from Defatted Rice Bran.

L. Chen and D. F. Houston. Copyright 1970 by the American Association of Cereal Chemists, Inc. 

Alkaline extraction of defatted California rice bran removed 33.3 to 82.5% of total crude protein as pH increased from 7 to 12 when the bran was stirred 1 hr. at 25 C. with 7.5 vols. of extractant (optimal conditions). Grinding the bran had little effect, though solubilization of protein and total solids increased somewhat at and above pH 10. Much of the extracted protein was separated by isoelectric precipitation (pH 5.5); a further small amount was coagulated by heating. About 16 to 17% of total crude protein remained soluble after isoelectric precipitation; about half the nitrogen in this fraction was dialyzable. At pH 11, which was optimal, nuetralization and drying of the extract yielded about 50% of the bran protein as a 40% concentrate. Drying of the separated solids precipitated at pH 5.5 from the pH 11 extract yielded about 37% of the bran protein as an 85% concentrate. Gel electrophoresis showed multiple components in both soluble and precipitated fractions of the extracted protein.