Cereal Chem. 71:162-165   |  VIEW ARTICLE


Esterase Activity and Free Fatty Acid Accumulation in the Bran of Selected Rice Cultivars.

W. Tsuzuki, H. Kasumimoto, S. Kobayashi, and T. Suzuki. Copyright 1994 by the American Association of Cereal Chemists, Inc. 

To increase our understanding of lipid degradation in rice bran, the esterase activities of crude enzyme solutions extracted from rice bran were compared for 10 rice cultivars. The activities of rice cultivars Kinuhikari, Saikai191, and Hishiyutaka were higher than those of other rice cultivars we examined. Changes in the free fatty acid content of the polished bran from four rice cultivars were studied using by fluorometric high-performance liquid chromatography using 9-bromomethylacridine. Free fatty acids in the polished bran of Saikai191 and Hoshiyutaka accumulated more rapidly than the those of Tomochi396 and Koshihikari, which supports the observation that the esterase activity in polished bran is cultivar-dependent. Furthermore, the species of free fatty acids that accumulated in the polished rice bran differed depending upon the storage conditions. This suggests that the storage temperature and relative humidity affected the activities of several enzymes that participate in the lipid hydrolysis.