Abstract:

In order to evaluate the antioxidant activity and molecular weight distribution of in vitro digestion product of flying squid (Ommastrephes batramii) skin-gelatin, the preparation of flying squid skin-gelatin hydrolysate derived from in vitro gastrointestinal (GI) digestion (SHGD) was performed using a simulated model and SHGD was analyzed for its amino acid composition, antioxidant effects (reducing power, inhibitory effect on lipid autooxidation and free radical scavenging capacity) and molecular weight distribution. SHGD was rich in antioxidant amino acids including tyrosine, histidine, proline, alanine and leucine, and their total content was 32.78%. The content of total hydrophobic amino acids (THAA) (37.48%) was comparatively higher than that of skin-gelatin. With increasing concentration from 20 mg/mL to 25 mg/mL, the reducing power of SHGD presented no obvious change, and was similar to that of butylated hydroxyanisole (BHA). At concentrations of 16 mg/mL and 12 mg/mL, SHGD showed better ability to scavenge DPPH free radicals than BHA and α-tocopherol, respectively. The scavenging rates of SHGD at 25 mg/mL against hydroxyl and superoxide anion free radicals were (81.93±2.02)% and (72.26± 2.12)%, respectively. Meanwhile, SHGD was a stronger inhibitor against lipid peroxidation when compared to BHA. At the same concentration conditions, flying squid skin-gelatin was remarkably inferior to SHGD in antioxidant effect. Furthermore, based on our experimental results, it is deduced that the fractions of SHGD having a molecular weight varying from 383 to 1492 u might be responsible for its antioxidant activity.

Key words: flying squid, skin-gelatin, gastrointestinal digestion, antioxidant, hydrolysate