按照Osbron法提取米糠中的清蛋白、球蛋白、醇蛋白、谷蛋白,并对4种蛋白进行功能性质评价。结果表明:米糠中清蛋白、球蛋白、醇蛋白、谷蛋白占米糠蛋白总量依次是56.93%、20.84%、3.167%、19.06%;等电点依次是pH4.0、4.0、5.0、4.6。4种蛋白的功能性质对比评价表明:清蛋白的持水性最大,醇蛋白的乳化性最高,清蛋白在等电点处的起泡性最差。SDS—PAGE凝胶电泳分析表明:清蛋白分子的亚基组成分子质量为95.43、76.51、52.85kD;球蛋白的亚基组成分子质量为103.12、76.51kD;醇蛋白的亚基组成分子质量为14.00kD;谷蛋白的亚基组成分子质量为36.29、20.00、14.00kD。
Four protein isolates including albumin, globulin, gliadin and glutenin were extracted from rice bran using the Osbron method and their functional properties were evaluated. Albumin, globulin, gliadin and glutenin accounted for 56.93%, 20.84%, 3.167% and 19.06% of total proteins in rice bran, respectively, and their isoelectric points were 4.0, 4.0, 5.0 and 4.6, respectively. Comparative evaluation of functional properties showed that albumin possessed the highest water- binding capacity but the weakest foaming capacity at the isoelectric point, and glutenin had the highest emulsibility. SDS- PAGE suggested that the subunit molecular weights were 95.43, 76.51 kD and 52.85 kD for albumin, 103.12 kD and 76.51 kD for globulin, 14 kD for gliadin, and 36.29, 20.00 kD and 14.00 kD for glutenin, respectively.