State Key Laboratory of Food Science and Technology, School of Food Science and Technology, National Engineering Research Center for Functional Food, National Engineering Laboratory for Cereal Fermentation Technology, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, Jiangnan University, 1800 Lihu Road, Wuxi 214122, Jiangsu, People's Republic of China.
Food Funct. 2020 Apr 30;11(4):3144-3155. doi: 10.1039/c9fo01783f.
The degree of hydrolysis (DH) plays important roles in the characteristics of food proteins. Herein, in order to explore the effects of partial hydrolysis on the structural, functional and antioxidant characteristics of hydrolysates, oat protein isolate was partially hydrolyzed with alcalase at different DHs (2%, 4%, 6%, 8%, 12%, and 16%). Our results showed that hydrolysis could induce significant structural changes in oat protein, mainly reflecting at the amino acid pattern, molecular weight profile and protein conformation. Alcalase hydrolysis also resulted in hydrolysates with the emulsifying activity index of at least 19.83 m2 g-1, and the highest emulsion stability was observed in the hydrolysate with a DH of 6%, possibly due to its suitable molecular weight, exposed hydrophobic amino acid residues and high surface net charge. Besides, all hydrolysates exerted excellent DPPH radical scavenging activity with an IC50 value ranging from 19.23 to 30.32 μg mL-1, which was closely correlated with DH. The oat protein isolate with moderate alcalase hydrolysis (DH 6%) exhibited the strongest metal ion-chelating activity and possessed the maximum amount of hydrophilic amino acids. More importantly, the oat protein hydrolysate with a DH of 6% not only prolonged the induction period of sunflower oil, but also improved the stability of the sunflower oil-in-water emulsion, as evidenced by the reduced TBARS production and the homogeneous droplet size. Therefore, partial hydrolysis can be advantageous for improving the functional and antioxidant characteristics of oat protein isolate, particularly the hydrolysate with a DH of 6%.
水解度（DH）在食品蛋白质的特性中起着重要作用。在此，为了探索部分水解对水解产物结构、功能和抗氧化特性的影响，采用碱性蛋白酶对燕麦分离蛋白进行不同 DH（2%、4%、6%、8%、12%和 16%）的部分水解。结果表明，水解可以诱导燕麦蛋白发生显著的结构变化，主要反映在氨基酸模式、分子量分布和蛋白质构象上。碱性蛋白酶水解还导致水解产物具有至少 19.83 m2 g-1 的乳化活性指数，在 DH 为 6%时观察到最高的乳液稳定性，这可能是由于其适宜的分子量、暴露的疏水性氨基酸残基和高表面净电荷。此外，所有水解产物均表现出优异的 DPPH 自由基清除活性，IC50 值范围为 19.23-30.32 μg mL-1，与 DH 密切相关。适度碱性蛋白酶水解（DH 6%）的燕麦分离蛋白表现出最强的金属离子螯合活性，且具有最多的亲水氨基酸。更重要的是，DH 为 6%的燕麦蛋白水解产物不仅延长了葵花籽油的诱导期，而且改善了葵花油-水乳液的稳定性，这可以从 TBARS 生成量减少和均匀的粒径得到证明。因此，部分水解有利于改善燕麦分离蛋白的功能和抗氧化特性，特别是 DH 为 6%的水解产物。
