Effects of Lactic Acid Bacteria on Nitrite Degradation during Pickle Fermentation

Abstract

Two strains with nitrite degradation ability were obtained from Kimchi. According to morphology, Gram-stain, physiological tests, the isolates were identified primarily as Lactobacillus brevis and Lactobacillus plantarum, respectively. Comparing the nitrite degradation rate of two strains, the strain L. plantarum Z1 with higher degradation rate was utilized to investigate effects on sodium nitrite degradation (NaNO2) during pickle fermentation. The strain L. plantarum Z1 was inoculated to 200mL MRS medium including 120μg/mL NaNO2 with inoculum of 1% after culturing at 30°C for 18 h. Several experiments that involved different temperature, pH, substrate concentration were carried out. Nitrite degradation ability of L. plantarum Z1was estimated from detection of the residue concentration of NaNO2. The optimal conditions for nitrite degradation were: growing temperature at 30°C, initial pH at 5.5 and substrate concentration of 400μg/mL. Under these conditions, the nitrite degradation efficiency was up to 96% with residue of 4.8μg/mL which is below the content of National Standards. The ability to degrade sodium nitrite provided a tool for LAB (Lactic acid bacteria) application to improve their industrial performance.