Optimized Production and Bioactivities of Protein Hydrolysates from Atlantic Salmon Processing Discards

Enzymatic hydrolysis of Atlantic salmon processing discards, including heads and frames, was carried out using Alcalase, Flavourzyme, and their combination. The degree of hydrolysis varied depending on the enzyme and substrate, ranging from approximately 5% to 15%. Alcalase was more effective than Flavourzyme for the hydrolysis of salmon frames and heads. The results also indicated that 1% enzyme concentrations had slightly higher mean DH than 2%. The bioactivity testing indicated that the head hydrolysates had superior DPPH scavenging activity, while frame hydrolysates demonstrated higher ABTS and hydroxyl radical scavenging activity. The correlation between DH and bioactivities indicated that the degree of hydrolysis did not have any significant effect on the DPPH and hydroxyl radical scavenging activities while demonstrating a significant positive correlation against ABTS scavenging activity.