碱法提取联合高温和酶法改性米糠蛋白的研究

Study on alkaline extraction joint heat and enzymatic modification of rice bran protein

以脱脂米糠为原料,氮溶指数为指标,通过均匀设计优化碱法提取联合高温和酶法改性米糠蛋白工艺。得到最优条件为:提取温度50℃,高温改性时间4 min,酶解时间120 min,改性后的米糠蛋白氮溶指数达到96.08%。在该条件下,改性米糠蛋白的持水性、持油性、乳化性和乳化稳定性分别提高了15.8%、165.7%、48.9%和84.7%。通过对米糠蛋白游离巯基和二硫键含量测定和SDS-PAGE电泳分析表明,碱法提取联合高温和酶法改性米糠蛋白可使米糠蛋白中二硫键含量减少,游离巯基含量增加,蛋白水解,溶解度增加,从而改善其功能特性。

The rice bran protein was alkaline extracted jointing with beat and enzymatic modification by using fresh defatted rice bran as raw materials and nitrogen solubility index as index.The process was optimized by uniform design.The best conditon parameters were as follows：extraction temperature 50 ℃, heat modification time 4 min and enzymatic reaction time 120 min.The nitrogen solubility index of modified rice bran protein reached 96.08%. Under the optimum conditions, water absorption, oil absorption, emulsion and emulsion stability were increased by 15.8% , 165.7% , 48.9% and 84.7% , respectively. Finally, free thiol groups and disulfide bonds determination and SDS-PAGE electrophoresis indicated that alkaline extracted and heat and enzymatic modified rice bran protein increased its functional properties by decreasing disulfide bonds, increasing free thiol groups, which led to the hydrolysis of rice bran protein and improvement of solubility.