Characterization and selection of Lactobacillus brevis starter for nitrite degradation of Chinese pickle

Abstract

To improve the safety of Chinese pickles, lactic acid bacteria were isolated from traditional fermented foods to test for nitrite degradation during the pickling process. Lactobacillus brevis AR123 was screened out as a starter culture for pickle fermentation. L. brevis AR123 has a high tolerance to nitrite and salt. During pickle fermentation, the nitrite peak appeared from 12 to 24 h in the pickle juice and was delayed to 24–48 h in the pickles. In 6% salt, L. brevis AR123 and a commercial starter could rapidly lower the pH of the pickles, and the nitrite contents were 0.83 mg kg−1 and 3.05 mg kg−1, respectively, in pickles at 72 h. Meanwhile, no obvious nitrite peak was observed for the pickle inoculated with a mixed starter; it had a low nitrite level (0.88 mg kg−1 at 72 h). However, the concentration of nitrite was as high as 17.92 mg kg−1 in the spontaneous fermentation group. During pickle fermentation, Lactic acid bacteria (LAB) population increased significantly when salt concentration was 4%–8%, and sensory analysis shown that the L. brevis AR123 inoculated pickle exhibited better sensory evaluation results than spontaneous fermentation pickle. In conclusion, inoculation with L. brevis AR123 alone or combined with a commercial starter (mixed starter) is effective in removing nitrites and enhancing the sensory properties of pickle. LAB could accelerate degradation of nitrite significantly and shorten the fermentation time for pickle process.