Optimization of Enzyme-assisted Extraction of Bioactive Peptides from Whiteleg Shrimp (Litopenaeus vannamei) Head Waste Using Box-Behnken Design

Whiteleg shrimp (Litopeneaus vannamei) processing lines discard huge quantities of head wastes, which are the protein-rich source. Enzymatic hydrolysis has been studied for decades to salvage discarded whiteleg shrimp head waste to produce high-added value products applicable to animal industry. Alcalase 2.5 L, which is widely applied on marine materials, was used to hydrolyze whiteleg shrimp head waste protein and then purified by cold absolute ethanol. Hydrolysis conditions including enzyme/substrate (E/S) ratio, incubation temperature and duration were preliminarily screened (E/S ratio 0–2.5%, temperature 50–70 °C, duration 30–90 min) before conducting optimization using Box-Behnken design. After optimization, collected protein hydrolysate reached an experimental yield of 61.64% on dry basis under the optimal conditions as treated by Alcalase 2.5 L at 0.9% E/S ratio and incubated at 62 °C for 65 min. Protein hydrolysate performed bioactivity including DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity (3.88 ± 0.10 mg Trolox equivalents g dry matter–1), reducing power (19.20 ± 0.52 mg Trolox equivalents g dry matter–1) and α-amylase inhibitory activity (10.74 ± 0.65% inhibition at 50 mg mL–1).