Key Laboratory of Carbohydrate Chemistry and Biotechnology Ministry of Education State Key Laboratory of Food Science and Technolog, Jiangnan University, Wuxi, 214122, China.
Food Funct. 2020 Jan 29;11(1):871-882. doi: 10.1039/c9fo00038k.
This research focused on the effects of electron beam irradiation (EBI) on the hydrolysis and antioxidant activity of rice proteins (RPs). The RPs were treated with 0, 5, 10, 20 and 30 kGy doses of EBI. The results showed that EBI pretreatment improved significantly (P < 0.05) the degree of hydrolysis, increasing the DH value by more than 15.09% at a dose of 30 kGy. In addition, radical scavenging results showed that EBI treatment had effects on antioxidant activity and could increase the DPPH and ABTS+ radical scavenging activity of rice protein hydrolysates (RPHs) by 32.06% and 79.11%, respectively (30 kGy). The CAA test also confirmed that EBI pretreatment could effectively improve the ability of RPHs to remove intracellular free radicals. Scanning electron microscopy indicated that EBI treatment destroyed microstructures and resulted in cracks and fragments of RPs. Circular dichroism analysis showed that EBI affected the secondary structure of RPs by destroying the α-helix structure. Changes in the UV visible spectra indicated unfolding of RPs by EBI. Amino acid and molecular weight distribution analysis revealed that EBI pretreatment could increase the ratio of antioxidant-related amino acids and produce smaller peptides. Therefore, EBI pretreatment is an efficient method to promote protein proteolysis due to its effect on the molecular conformation as well as on protein microstructure. Moreover, EBI treatment applied before enzymatic hydrolysis has the potential to prepare hydrolysates with high bioactivity.
本研究聚焦于电子束辐照（EBI）对大米蛋白（RPs）水解和抗氧化活性的影响。RPs 经 0、5、10、20 和 30 kGy 剂量的 EBI 预处理。结果表明，EBI 预处理显著提高（P < 0.05）水解度，在 30 kGy 剂量下，DH 值增加超过 15.09%。此外，自由基清除结果表明，EBI 处理对抗氧化活性有影响，可使大米蛋白水解物（RPHs）的 DPPH 和 ABTS+自由基清除活性分别增加 32.06%和 79.11%（30 kGy）。CAA 试验也证实，EBI 预处理能有效提高 RPHs 清除细胞内自由基的能力。扫描电子显微镜表明，EBI 处理破坏了 RPs 的微观结构，导致其出现裂缝和碎片。圆二色分析表明，EBI 通过破坏α-螺旋结构影响 RPs 的二级结构。紫外可见光谱的变化表明，EBI 使 RPs 展开。氨基酸和分子量分布分析表明，EBI 预处理能增加与抗氧化相关的氨基酸比例，并产生较小的肽。因此，EBI 预处理是一种促进蛋白质水解的有效方法，这归因于其对分子构象以及蛋白质微观结构的影响。此外，在酶解之前进行 EBI 处理，有潜力制备具有高生物活性的水解物。
