Esterase activity and free fatty acid accumulation in the bran of selected rice cultivars.
Tsuzuki, W.; Kasumimoto, H.; Kobayashi, S.; Suzuki, T.;
Cereal Chemistry Year: 1994 Vol: 71 Issue: 2 Pages: 162-165 Ref: 18 ref.
1994
บทคัดย่อ
ABSTRACT :
The accumulation of free fatty acids in rice seed and the associated rancidity is a problem during storage. With a view to investigating lipid degradation in rice bran, the esterase activities of crude enzyme solutions extracted from rice bran were compared in 10 rice cultivars. The esterase activities of rice cultivars Kinuhikari, Saikai 191 and Hishiyutaka were higher than those of the other rice cultivars examined. Changes in the free fatty acid content of the polished bran from four rice cultivars were studied using fluorometric high-performance liquid chromatography using 9-bromomethylacridine. Free fatty acids in the polished bran of Saikai 191 and Hoshiyutaka accumulated more rapidly than the those of Tomochi 396 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 storag
e temperature and relative humidity affected the activities of several enzymes that participate in the lipid hydrolysis.