Abstract: This study investigated the effect addition of different amounts of sodium nitrite on microbial growth, lipid oxidation and volatile compounds in naturally fermented Harbin air-dried sausages. It was found that the addition of sodium nitrite had no significant influence on the pH value, water activity, or the growth of total bacterial count and lactic acid bacteria (P > 0.05) during the fermentation of sausages, but the growth of Escherichia coli was significantly inhibited (P < 0.05) by addition of nitrite at levels higher than 0.10 g/kg. Sodium nitrite had good coloring effect when added at 0.10 g/kg to sausages. The results of peroxide value and thiobarbituric acid reactive substances (TBARS) value showed that nitrite at 0.10 g/kg was effective in inhibiting lipid oxidation. The residual nitrite level was gradually reduced during fermentation and did not significantly different among different treatments at the end of fermentation (P > 0.05). Meanwhile, the addition of sodium nitrite had no significant influence on the amounts of volatile compounds produced by carbohydrate fermentation and amino acid degradation (P > 0.05), but significantly influenced the amounts of aldehydes and ketones from lipid oxidation (P < 0.05); the more sodium nitrite was added, the stronger inhibition of lipid oxidation was observed.

Key words: sodium nitrite, natural fermentation, air-dried sausages, microbial growth, lipid oxidation, volatile compounds