59D-13 |
Effect of extraction conditions on protein solubility of defatted wheat germ |
S. PHIMPHILAI, R. D. Galyean, A. B. Bodine, F. B. Wardlaw, and J. R. Rieck. Dept. of Food Science & Human Nutrition, Clemson Univ., 224 Poole Agricultural Center, Box 340371, Clemson, SC 29634-0371
Wheat germ protein is a rich source of amino acids, especially lysine. Recent research has been directed to the study of wheat germ utilization, particularly in the area of isolation of functional proteins. However, studies of the optimum conditions related to the presence of lysinoalanine, a toxic substance, have not been reported. In this study, solubility of proteins in wheat germ was investigated under different temperature and pH conditions to optimize isolation. Pulverized defatted wheat germ was used as raw material. Proteins were extracted in 0.1N NaCl solution under alkaline conditions (pH 8, 9, 10) at 30°C, 50°C, or 70°C. Protein content in NaCl extracts increased at higher pH and/or temperature conditions. Lysinoalanine was found in extracts obtained at conditions of pH 10 at 50°C and 70°C, and pH 9 at 70°C. Denatured protein was clearly shown by SDS-PAGE analyses in extracts obtained at pH 10 and 70°C. There was no difference in lipase inhibitory characteristics of wheat germ proteins. Extracts obtained at pH 8 and 70°C was concluded to be an optimum condition for protein solubility for further studies in utilization of processed wheat germ proteins.
Session 59D, Food Chemistry: Proteins and Physicochemical Properties
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