Nutritional evaluation and functional properties of the antioxidant polypeptide from Zanthoxylum bungeanum Maxim seeds kernel protein hydrolysate

Antioxidant polypeptides of Zanthoxylum bungeanum Maxim seeds kernel (ZBMSK) were investigated based on molecular weight distribution, amino acid composition, and functional properties. The polypeptide had a molecular weight distribution of 1026 ~ 2249 Da and 4926 ~ 6398 Da, and was rich in glutamic acid, arginine, aspartic acid, and leucine, but poor in cysteine and tryptophan. Total amino acids were 56.42 g/100 g, and lysine was the first limiting amino acid. The polypeptide showed excellent solubility, viscosity, emulsifying properties, and foam expansion compared with its original protein. In addition, the polypeptide exhibited favorable reduction power and scavenging capacities for DPPH radicals with an IC50 value of 8.86 mg/mL. These results suggest that the polypeptide derived from ZBMSK has potential future application among functional foods, and may be a promising source of natural antioxidants.