Improving tyrosinase inhibitory activity of grass carp fish scale gelatin hydrolysate by gastrointestinal digestion: Purification, identification and action mechanism

Biologically active peptides with tyrosinase inhibitory activity may be important raw materials in the field of whitening foods. Gastrointestinal digestion was employed to obtain components with higher tyrosinase inhibitory activity from the grass carp fish scale gelatin hydrolysates. The results revealed that the product had stronger tyrosinase inhibitory activity after gastrointestinal digestion than before. The digested products were screened using bioaffinity ultrafiltration for tyrosinase inhibitory activity for the first time, yielding 6 peptides. As a reversible competitive inhibitor, FTGML showed the highest IC50 value of 1.89 mmol/L. The main forces between FTGML and tyrosinase was dominated by hydrogen bonding and hydrophobic interaction. Zebrafish models for skin whitening and lightning were established respectively to verify the effect of FTGML in vivo, and it was discovered that FTGML concentrations of 125 μg/mL and 62.5 μg/mL had the best whitening and lightning effects, respectively.