米渣肽双酶两步水解法制备过程中物化特性与结构变化

Physicochemical properties and peptide pattern changes in rice dreg peptides prepared by double enzyme hydrolysis

探究双酶法制备米渣蛋白肽过程肽的组成结构变化.基于前期研究基础,采用双酶法以胰蛋白酶+风味蛋白酶,中性蛋白酶+风味蛋白酶4 h内分别连续制备两类米渣肽RDPH-1和RDPH-2.随着反应的进行,发现前者较后者水解更快速且程度更深,4 h时水解度分别为29.09与16.47;米肽产物平均粒度大多<1000 nm,同时粒度与分子结构随着米肽的酶解与聚集发生动态变化;表面疏水性都呈先下降后上升的趋势,且前者较后者整体大10倍多;RDPH-1较RDPH-2二级结构更稳定,两者的氨基酸组成不同,但主要成分相似,营养价值相当.该法制备米渣肽的过程研究表明,胰蛋白酶和风味蛋白酶更适合酶解米渣得到小分子肽,且具有规律性,对肽的高效制备具有指导意义.

The changes in composition of rice dreg peptides prepared by double enzymatic hydrolysis were investigated. Two kinds of rice dreg peptides were prepared by 4 h hydrolysis. Of which,RDPH-1 was prepared using trypsin and flavor protease,RDPH-2 was using neutral protease and flavor protease. As the reaction proceeded,the former hydrolysis was found to be faster and more thorough than the latter,and the hydrolysis degrees at 4 h were 29.09% and 16.47%,respectively. The average particle size of the rice peptides was mostly less than 1 000 nm. Both the particle sizes and molecular structures changed dynamically along with enzymatic dissociation and aggregation. Moreover,the surface hydrophobicity of the peptides firstly decreased and then increased,with the former was 10 folds larger than the latter. Furthermore,the secondary structure of RDPH-1 was more stable than that of RDPH-2. In spite of the differences between their amino acid compositions,the nutritional values were similar. In summary,the effectiveness of trypsin and flavor protease in combination was remarkable to produce small peptides from rice dregs,which has a guiding significance for efficient preparation of small molecular rice peptides.