Zhang Yanyan, Li Jing, Li Suyun, Ma Haile, Zhang Hua
School of Food and Biological Engineering, Zhengzhou University of Light Industry, Zhengzhou, China.
School of Food and Biological Engineering, Jiangsu University, Zhenjiang, China.
J Sci Food Agric. 2018 Mar;98(4):1530-1538. doi: 10.1002/jsfa.8624. Epub 2017 Sep 21.
Ultrasound pretreatment could improve the angiotensin-I converting enzyme (ACE) inhibitory activity of hydrolysates of wheat gluten (WG). The working mode of ultrasound has an important effect on the enzymatic hydrolysis of protein.
The results showed that the optimum working mode of ultrasound was alternate dual-frequency mode (20/35 kHz), substrate concentration was 30 g L , initial temperature of the suspension was 30 °C, ultrasound pretreatment time was 10 min and power density was 150 W L . Under optimised conditions, ACE inhibitory activity of WG hydrolysates reached to its maximum value in advance. The surface hydrophobicity (H ) of WG and the content of small peptides at the beginning of the enzymolysis were improved by the ultrasound pretreatment. The structure of WG was destroyed by the ultrasound pretreatment. The enzymatic residue of ultrasound pretreated WG were damaged greater than control.
It was concluded that alternate dual-frequency ultrasound pretreatment improved the ACE inhibitory activity. Ultrasonic pretreatment may loosen the tissue of WG aggregate, and help the enzyme alcalase to attack the interior of WG aggregate easily, which resulted in the release of low molecular weight peptides from WG aggregate. © 2017 Society of Chemical Industry.
超声预处理可提高小麦面筋（WG）水解产物的血管紧张素-I转换酶（ACE）抑制活性。超声的工作模式对蛋白质的酶解有重要影响。
结果表明，超声的最佳工作模式为交替双频模式（20/35kHz），底物浓度为30g/L，悬浮液初始温度为30℃，超声预处理时间为10min，功率密度为150W/L。在优化条件下，WG水解产物的ACE抑制活性提前达到最大值。超声预处理提高了酶解开始时WG的表面疏水性（H）和小肽含量。超声预处理破坏了WG的结构。超声预处理WG的酶解残渣比对照受损更严重。
得出交替双频超声预处理提高了ACE抑制活性的结论。超声预处理可能会使WG聚集体的组织疏松，并有助于碱性蛋白酶更容易地攻击WG聚集体内部，从而导致低分子量肽从WG聚集体中释放出来。©2017化学工业协会。
