高温米糠粕中蛋白质的提取工艺优化

Optimization of Extraction Technology of Protein from High Temperature Rice Bran Meal

米糠粕在热稳定化加工过程中蛋白质容易发生变性,导致可溶性蛋白减少,给米糠蛋白的提取带来困难。为了研究高温米糠粕中蛋白的提取工艺,本试验比较了碱法、碱法+超声波、碱法+超声波+碱性蛋白酶三种方法,结果发现,采用碱法+超声波+碱性蛋白酶提取的米糠蛋白得率最高,为3.98%;然后考察了碱性蛋白酶添加量、酶解时间、酶解后pH值对蛋白得率的影响。在单因素试验的基础上,采用正交试验对米糠蛋白的提取工艺进行了优化,结果表明,三个因素均是影响米糠蛋白得率的极显著因素,影响顺序依次为酶解时间>蛋白酶添加量>酶解后pH值;最佳的提取条件为碱性蛋白酶添加量1.5%、酶解时间1 h、酶解后pH值11.0。在此条件下,米糠蛋白得率为7.10%,比优化前(0.12%)提高了6.98%;蛋白含量为70.5%。

In the process of heat stabilization of rice bran meal,protein denaturation is easy to occur,which leads to the decrease of soluble protein and makes the extraction of rice bran protein difficult.In order to study the extraction technology of protein in high temperature rice bran meal,this experiment compared three extraction methods:alkali method,alkali method+ultrasonic,alkali method+ultrasonic+alkaline protease.The results showed that the yield of protein extracted by alkali method+ultrasonic+alkaline protease was the highest,which was 3.98%.The effects of alkali protease addition,enzymatic hydrolysis time and pH after enzymatic hydrolysis on the yield of rice bran protein were investigated.On the basis of single factor experiment,the extraction process of rice bran protein was optimized by orthogonal experiment.The results showed that three factors all were extremely significant factors and the order of three factors affecting the yield was enzymatic hydrolysis time>alkali protease addition>pH after enzymatic hydrolysis.The optimum extraction conditions were alkali protease addition of 1.5%,enzymatic hydrolysis time of 1 h and pH 11.0 after enzymatic hydrolysis.Under these conditions,the extraction rate of rice bran protein reached 7.10%,which was 6.98% higher than that of before optimization(0.12%),and the protein content was 70.5%.