Participation of Atp-Related Compounds in the Change of Antioxidant Capacity with the Deterioration of Swordtip Squid (loligo Edulis)

We investigated the antioxidant capacity and peroxy radical scavenging activity of raw mantle tissue extract of the swordtip squid Loligo edulis at various freshness levels using the chemiluminescence method. The antioxidant capacity of the extract was highest at K value, which is an index for freshness of fish and shellfish, of 20-40% (P < 0.05). The antioxidant capacity decreased at K values of above 40%, and there were no significant difference among K value 40-60%, 60-80% and above 80% (P < 0.05).Among the ATP-related compounds in the extracts, the main compounds were AMP and hypoxanthine. The correlation between antioxidant capacity and the amount of hypoxanthine was high especially at K value of above 80%. However, the participation of ATP-related compounds in the total antioxidant capacity was low, though they have some antioxidant capacities.Present study is the first report to show the participation of ATP-related compounds on the antioxidant capacity of squid with deterioration.PRACTICAL APPLICATIONSATP-related compounds, which are included in fish and shellfish, are constituent factors of K value, which is important for a freshness index. We inspected the possibility of ATP-related compounds for the participation to antioxidant capacity that is one of important functions of the food. The result of this study newly showed the superiority of good freshness by clarifying that fresh squid has a higher antioxidant capacity. Freshness optimized both palatability and food hygiene. The participation of ATP-related compounds in the total antioxidant capacity was low. However, the contribution ratio was gradually increased. This result gave us the opportunity to inspect the participation of the ATP-related compounds to the antioxidant capacity in the other foods.