关键词: 米糠, 米糠蛋白, 蛋白质氧化, 酶解产物, 抗氧化性

Abstract: In order to study effect of rice bran rancidity on antioxidative activity of rice bran protein hydrolysates, rice bran protein which prepared by rice bran with different storage time was used as material to prepare hydrolysates by enzymatic hydrolysis using alcalase, oxidation extent of rice bran oil and rice bran protein and antioxidative activity of rice bran protein hydrolysates which prepared by rice bran with different storage time were investigated. The results indicated that storage of rice bran lead to hydrolysis and oxidation of rice bran oil as well as oxidation of rice bran protein, and disulfide as well as non-disulfide covalent bond participated in the formation of oxidation aggregates of rice bran protein. As storage time of rice bran increased, degree of hydrolysis (DH) of rice bran protein firstly increased, and then decreased, reached maximum value after storage of 3 days. Free radical scavenging ability on 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), superoxide (O2-?), radicals hydroxyl (?OH), and metal chelating ability of rice bran protein hydrolysates firstly increased, and then decreased. The results indicated that short-term storage of rice bran increased DH of rice bran protein, and increased antioxidant activity of rice bran protein hydrolysates. Long-term storage of rice bran limited DH of rice bran protein, and reduced antioxidant activity of rice bran protein hydrolysates.

Key words: rice bran, rice bran protein, protein oxidation, hydrolysates, antioxidative activity