Abstract: Lactobacillus paracasei HD1.7, isolated from spent brine from pickled Chinese cabbage, was used as a starter culture to establish and investigate a microbial ecosystem model for pickled Chinese cabbage fermentation, i.e., HD1.7 fermentation in comparison with natural fermentation as control. High performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) were adopted to detect organic acid, acidity, nitrite, VC, glycerol, ethanol, mannitol, 2,3-butanedilol and volatile flavor compounds in the model and control groups and eight commercial products. It was found that the organic acid content and acidity were positively correlated in all samples. The organic acids contents of Heida branded pickled Chinese cabbage, HD1.7 fermented Chinese cabbage and Yuanziyuanwei branded pickled Chinese cabbage were (13.21 ± 0.13), (13.20 ± 0.17) and (13.13 ± 0.13) g/L, respectively, which were higher than those of other samples. Furthermore, Heida branded pickled Chinese cabbage, HD1.7 fermented Chinese cabbage and Bianfuji branded pickled Chinese cabbage showed a significantly lower nitrite concentration and a significantly higher VC concentration (P < 0.05) and therefore had better safety and nutritional value than did other samples in addition to higher contents of flavor compounds and better sensory quality. In conclusion, these results may help to monitor the production process of pickled Chinese cabbage and establish quality standard for pickled Chinese cabbage and they are of great practical significance to enhance the quality stability of pickled Chinese cabbage and the level of industrial development.In addition, these results also indicate the promising application potential of L. paracasei HD1.7 as a starter culture in industrial production of pickled Chinese cabbage.

Key words: pickle Chinese cabbage, quality, starter culture, Lactobacillus paracasei, metabonomics, mass spectrometry