Isolation of lactic acid bacteria from Chinese pickle and evaluation of fermentation characteristics

The aim of the investigation was to isolate lactic acid bacteria (LAB) from Chinese pickle, which could improve the quality of pickle by inoculation fermentation. In this study, three LAB were selected from pickle, based on 16S rDNA sequencing, which were named L. fermentum FM 8, L. sp FM 10, and L. plantarum FM 17, respectively. These strains were independently introduced in pickles during fermentation to investigate their effects on fermentation. Compared with naturally fermented pickle samples, pickle samples inoculated with L. fermentum FM 8 or L. plantarum FM 17 required less time for fermentation and had lower nitrite levels. After four kinds of pickle (without inoculation, inoculated with L. fermentum FM 8, inoculated with L. sp FM 10, inoculated with L. plantarum FM 17) were fermented at 25 degrees C for 15 days, these flavor-related components (organic acids, free amino acids, and volatile substances) were investigated. As results, partial least squares-discriminant analysis (PLS-DA) showed that samples of four groups could be divided into independent based on the flavor-related components, and 13 representative flavor-related compounds were selected characteristic with VIP (variable importance in projection) > 1. In addition, sensory evaluation showed that pickles inoculated with L. plantarum FM 17 had the highest overall acceptability scores. This study may help to develop strategies for reducing nitrite levels and improving the quality of pickles using L. plantarum FM 17 as a starter.