地衣芽孢杆菌碱性蛋白酶酶解改性玉米蛋白的研究

Enzymatic Hydrolysis of Modified Corn Protein by Alcalase from Bacillus Licheniformis

地衣芽孢杆菌碱性蛋白酶有限水解可改变玉米蛋白的结构和乳化性能,考察了pH值,温度,底物浓度等因素对水解反应的影响。结果表明:在pH值9,水解温度65℃,水解时间90 min,玉米蛋白质量分数5%以及[E]∶[S]比0.06 AU/g条件下水解度能达到34.05%;随水解程度的增大,玉米蛋白的水溶性和乳化活性呈线性相关性增加,水解度达到34.05%时,对应改性蛋白的乳化活性从原蛋白的8.2 m2/g提高到最大值37.8 m2/g。玉米蛋白的表面疏水性先增加后降低,分子柔性却随着水解度的增大而增加,但在整个水解过程中,玉米蛋白分子主要被降解为两个大的相似片段。

The restricted hydrolysis by alcalase from Bacillus licheniformis can alter the structure and emulating property of corn protein. The factors effecting on alcalase hydrolysis of corn protein were investigated. The best hydrolysis results can be obtained by conducting the hydrolysis at 65℃ with water addition 20 g/g protein, [E]：[S] 0.06 AU/g protein, pH 9 and 90 min, under which conditions the degree of hydrolysis of corn protein could arrive at 34.0%. Solubility and emulsion activity of modified corn protein increased as DH increase, and the hydrolysate with DH 34.05 resulted in the optimal improvement of EAI from 8.2 m^2/g to 37.8 m^2/g, compared with the wild protein. Hydrophobicity of the hydrolysate was increased to the maximum and then decreased as DH continued to grow, but flexibility of the hydrolysate was increased as DH increase, while the molecular weight of peptides in the optimal hydrolysate was mainly over two main peptides.