The stability of antioxidant peptides from squid and their anti-fatigue and anti-cancer activities

The change of scavenging activity on DPPH and hydroxyl free radicals of antioxidant peptides from squid was used as the index to study the effect of temperature, p H, different metal ions, preservatives and food ingredients on antioxidation stability of the peptides. At the same time, the anti-fatigue and anti-cancer activities of antioxidant peptides from squid were preliminarily studied.The results showed that antioxidant peptides from squid had strong heat-resistance, still maintaining more than 94% of the activity when heated to 100 ℃.The peptides maintained high activity under acidic conditions, but losed their activity under alkaline conditions.Surcrose and Na Cl had little effects on their antioxidation stability, but glucose and sodium benzoate lowered the oxidation stability of antioxidant peptides from squid ( p < 0.05) .Metal ions such as Ca²⁺, Mg²⁺, Zn²⁺and Cu²⁺affected the stability and the order was Cu²⁺> Zn²⁺> Mg²⁺> Ca²⁺. Antioxidant peptides from squid had better anti-fatigue activity.Compared with the blank, antioxidant peptides could prolong the exhaustive swimming time of mice to 23% ³6%.Antioxidant peptides from squid had significant inhibition on proliferation of gastric cancer cell SGC-7901.The inhibition rate of EC50 was 21.10 mg/m L.Therefore, the antioxidant peptides from squid were a kind of active peptide with anti-fatigue, anti-cancer activity and stable property.