Publication no. C-1997-0404-06R |  VIEW ARTICLE

Factors Affecting Yield and Composition of Zein Extracted from Commercial Corn Gluten Meal (1).

Shaowen Wu (2), Deland J. Myers (2,3), and Lawrence A. Johnson (2,4). (1) Journal Paper, J-16805 of the Iowa Agriculture and Home Economics Experiment Station, Ames, IA, 50011. Project no. 0161. Research supported by the Iowa Corn Promotion Board, Center for Crops Utilization Research and the Iowa Agriculture and Home Economics Experiment Station. (2) Graduate research assistant, associate professor and professor, respectively, Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011. (3) Corresponding author. E-mail: <dmyers@iastate.edu> (4) Professor-in-charge, Center for Crops Utilization Research, Iowa State University, Ames, IA, 50011. Cereal Chem. 74(3):258-263. Accepted January 19, 1997. Copyright 1997 by the American Association of Cereal Chemists, Inc.

Twelve corn gluten meal samples obtained from six wet-milling plants were processed into zein. Zein was extracted using 88% aqueous isopropyl alcohol at pH 12.5, followed by chilling. Protein recovery ranged from 21.3 to 32.0%, and protein purity ranged from 82.1 to 87.6%. Protein recovery increased as the protein purity increased (r = 0.76) (P < 0.01). One of the major factors influencing extraction yield was protein composition; especially alpha-zein content, which ranged from 53.4 to 64% of the total protein in the corn gluten meal samples. The intensity of red color of the corn gluten meal was negatively correlated with protein recovery and zein purity (r = -0.66 and -0.72, respectively) (P < 0.02).