Abstract:To explore the influence of drying methods on the quality of tuna oligopeptide powder，the structure，composition，and biological activity of spray-dried peptide powder and freeze-dried peptide powder were evaluated.The results showed that the molecular weight of tuna oligopeptides was almost entirely below 500 Da，with the freeze-dried sample exhibiting a lower molecular weight，stronger characteristic ultraviolet absorption peaks，higher total amino acid content，and greater retention of certain functional amino acids.Notably，the content of hydrophobic amino acids in the freeze-dried peptide powder was 16% higher than that in the spraydried counterpart.In terms of biological activity，the freeze-dried peptide powder also showed more pronounced antioxidant，anti-glycation，moisturizing，and tyrosinase inhibitory effects，indicating that the drying method affected the quality of tuna oligopeptides，with freeze-drying being more suitable for their production and processing.