燕麦分离蛋白的酶改性及其制品理化性质研究

Enzymatic Modification of Oat Protein Isolate and Product Properties

以燕麦分离蛋白(OPI)为原料,利用4种蛋白酶对其进行水解,观察水解进程曲线,选出碱性蛋白酶作为改性用酶。在对加酶量、料液百分比、反应时间的单因素试验基础上,采用Box-Benhnken响应面分析法,以水解度(DH值)为评定指标,得到了制备酶改性燕麦分离蛋白(EOPI)的最佳工艺参数:加酶量1 200 u/g、料液百分比2%、反应时间30 min。分析比较出了EOPI在溶解性、起泡性、乳化性上都明显高于OPI,在起泡稳定性和乳化稳定性上低于OPI;借助SDS-PAGE图谱和扫描电镜图了解到OPI分子质量较大的大颗粒蛋白分解成分子质量较小的小颗粒蛋白碎片;运用DSC测出了OPI和EOPI的变性温度分别为98.21℃和110.

Oat protein isolate（OPI） was hydrolyzed with four kinds of proteases separately,as a result alcalase was selected to modify OPI.Based on single factor tests including enzyme dosage,reaction time,and material percentage to water,employing Box-Behnken response surface methodology,using hydrolysis degree as evaluation index,the modification conditions were optimized.Results：The optimum enzymatic modification parameters of OPI are enzyme dosage 1 200 u/g,material percentage to water 2 %,and reaction time 30 min.Compared with the original OPI,the solubility,emulsifying activity and foaming ability of the modified OPI are better,whereas emulsifying stability and foaming stability are lower.SDS-PAGE and SEM show the big protein balls with large molecular weight in OPI change into small fragments with small molecular weight after the modification.The denaturation temperature of OPI and modified OPI,determined by DSC,is 98.21 ℃ and 110.51 ℃,respectively.