Ultrasound-assisted enzymatic hydrolysis of loach (Misgurnus anguillicaudatus) protein for antioxidant peptides: process optimization, structural characterization, and Keap1/Nrf2-mediated antioxidant mechanism
Zhongxing Chu, Guangfan Qu, Feiyan Yang, Zuomin Hu, Feijun Luo, Qinlu Lin
Abstract
Loaches are kinds of freshwater fish rich in protein, which have high development value. Loach protein hydrolysates were prepared by ultrasound-assisted enzymatic hydrolysis. The results showed, the hydrolysate exhibited strong antioxidant activity under the following conditions: ultrasonic power of 200 W, treatment time of 22 min, and neutral enzyme dosage of 10 KU/g. The structure characterization and analysis of hydrolysates under different treatments showed that ultrasound-assisted enzymatic hydrolysis could form more bioactive peptides with hydrophobic amino acids. A total of 2289 peptide sequences were identified, and 8 ideal peptide sequences were screened by combining biological activity score, hydrophobicity and other bioinformatics indicators. The binding energy between loach peptide and Keap1-Nrf2 protein was compared via molecular docking simulation. Among them, the binding energy between FG-14 and Keap1-Nrf2 was the highest (-86.43 kJ/mol). Subsequent experiments further verified the good antioxidant effect of FG-14. This study provides theoretical and technical support for high-value utilization of loaches.