Abstract: To study the stability of antioxidant peptides extracted from fermented sausage under conditions simulating those occurring during industrial processing and gastrointestinal digestion, we investigated the effects of temperature, pH, food additives, metal ions, and simulated gastrointestinal digestion on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, Fe2+-chelation ability and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cation radical scavenging activity. The results showed that the radical scavenging rate decreased significantly (P < 0.05) at high temperature and in acid and alkaline environment, while the Fe2+-chelation rate increased, but only slightly. NaCl, glucose and sucrose were beneficial to improve the radical scavenging activity, while they inhibited the Fe2+-chelation activity. NaNO2 had little effect on the antioxidant activity of the peptides when added at levels within the range permitted by the national standard. The antioxidant peptides were more sensitive to Cu2+ than to K+. The DPPH radical scavenging activity was completely lost after the simulated gastrointestinal (GI) digestion, but the Fe2+-chelation activity increased by 1.4 times compared with that before the digestion. The ABTS cation radical scavenging rate was stable at about 40%, and the total free amino acid content gradually increased.

Key words: stability; antioxidant peptides; fermented sausages