STABILITY OF ANTIOXIDANT PEPTIDES PREPARED FROM LARGE YELLOW CROAKER (Pseudosciaena crocea)

The effects of NaCl, temperature, pH, ultraviolet radiation, sugars, metal ions, and simulated gastrointestinal digestion were assessed on the antioxidant activity of peptides fractions from large yellow croaker (Pseudosciaena croacea) hydrolysate. The large yellow croaker peptides showed good stability when they were mixed with sugar and a low amount of NaCl, K+, or Ca2+. Temperatures lower than 60 degrees C and short exposure to ultraviolet irradiation were beneficial for the stability. Exposure to ultraviolet irradiation for longer than 24 h, or adding Fe2+, Fe3+, Zn3+, or Cu2+ caused significant damage to these peptides. Acidity and alkaline conditions suppressed one aspect of antioxidant activity but promoted another. The 2, 2-Biphenyl-1-picryhydrazyl radical scavenging activity of antioxidant peptides was increased when peptides were mixed with reducing sugars at 70 degrees C In addition, the antioxidant activity increased with exposure to pepsin for less than 30 min, but declined with extended gastric digestion or further intestinal digestion. These results suggested the peptides should be treated and maintained under proper conditions.