Protein Hydrolysate from Splendid Squid (Loligo formosana) Fins: Antioxidant, Functional Properties, and Flavoring Profile

Abstract

Protein hydrolysates (PH) from splendid squid fins (Loligo formosana) (SFPH) with different degrees of hydrolysis (DH) (10-40%) were prepared using alcalase and characterized. The yield of SFPH was increased with increasing DH (p<0.05). All SFPHs showed high protein content but low fat and ash contents. The lightness of SFPH was reduced with augmenting DH as advocated by increasing redness and yellowness (p<0.05). All SFPH samples having DH above 10% exhibited relative solubility higher than 90% (p<0.05). Foaming properties of SFPH were also improved with increasing DH. In general, antioxidant activities upsurged with increasing DH, except metal chelating activity and DPPH radical scavenging activity, which were decreased at higher DHs. Molecular weight (MW) of peptides was lowered with increasing DH as measured by size exclusion chromatography and SFPH having DH 40% (SFPH-40) possessed a higher proportion of peptides with smaller MW. SFPH-40 was rich in aspartic acid/asparagine and glutamic acid/glutamine. SFPH-40 had bitterness, especially at high concentrations. SFPH-40 contained a high number of volatile compounds associated with squid flavor. Thus, hydrolysates from squid fin could serve as an alternative nutrient with flavoring characteristics and antioxidant properties for food applications.