Preparation and Activity Evaluation of Anti-tyrosinase Peptides from Takifugu rubripes Skin Collagen

Response surface methodology (RSM) was employed to optimize the hydrolysis conditions of acid-soluble collagen (ASC) from Takifugu rubripes skin for the preparation of anti-tyrosinase peptides. The anti-tyrosinase and antioxidant activity of ultrafiltration peptides with different molecular masses were tested before and after being subjected to simulated gastrointestinal digestion, and the moisture absorption and retention properties were also evaluated to explore their application potential. The results showed that neutral protease was the most suitable enzyme for releasing antityrosinase peptides from T. rubripes skin collagen. The optimum process conditions were as follows: substrate concentration 2.9 g/100 mL, hydrolysis time 7.8 h, and enzyme dosage 7862 U/g. The hydrolysate obtained under these conditions inhibited tyrosinase activity by (35.14 ± 0.03)%. The molecular mass of the hydrolysate mainly ranged from 0 to 5 kDa, and the fraction CP-1 (< 3 kDa), with the highest anti-tyrosinase activity, scavenged 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation and hydroxyl radicals with half maximal inhibitory concentration (IC₅₀) values of 9.51, 2.03 and 7.29 mg/mL, respectively. CP-1 maintained high anti-tyrosinase and antioxidant activity after in vitro simulated digestion. In addition, CP-1 had high moisture absorption and retention properties and therefore could be used as a substitute for glycerol. This study may provide a theoretical basis for the deep processing and application of collagen peptides from T. rubripes skin.