Microbial Community Diversity Analysis During The Pickled Processing Of Vegetable With Low-salinity

Pickled vegetable has a long history, the appropriate salinity can improve the flavor, it is important to saveresource,reduce waste water of salinity and maintain vegetable’s nutrients. It presents an acttractive color andunique scent that can improve the product of quality. There are three different salinity of4%,6%,9%in this study,the number of microorganisms, the changes of physical and chemical indicators and sensory evaluation wereinvestigated during the phase of pickled brassia juncea. The results indicated that4%-6%of this range of salinitycan reduce the fermentation time and ensure the quality of product, it provides a appropriate salinity forsubsequent microbial community diversity analysis.Preservation of Brassica jumcea by low-salinity pickled processing is an important way to save resource,reduce the salinity wastewater and maintain the vegetable nutrition. Using16S rDNA clone library method,thebacterial diversity and its changes of critial indicators during different fermentation phase of low-salinity pickledbrassia juncea were investigated. The results indicated that the pickled system contained high diverse of bacteriaand mainly divided into two categories: Enterobacteriales and Lactobacillales.With the alteration of fermentationtime, bacterial community composition at five various stages showed the remarkable difference. TheEnterobacteriales of Enterobacter and Erwinia are the dominant microorganism in the initial stage of fermentation.In the late phase, the dominant microorganism is Lactobacillales of Lactobacillus, in which Lactobacillusplantarum plays a leading role in the pickled system. In addition, the pH and the total population of lactic acidbacteria changed accompany with the fermentation.Microbial community structure, population changes of microorganism and the quality character of pickledvegetables were investigated, respectively, in order to elucidate the predominant microorganisms involved inpickled processing of mustard tuber at the condition of low salt concentration. By means of16S rDNA clonelibrary and clone units analysis, the microbial diversity, predominant community and its changes were conductedduring different fermentation phase at5%and7%salinity of pickled mustard. The results showed thatLactobacillus, Leuconostoc and Weissella are the predominant community in the early stage of the5%saltconcentration system, but the dominant microorganism at7%system is Weissella hellenica. In the late phase ofpickled processing, Lactobacillus plantarum plays a leading role in the pickled system of mustard tuber. Inaddition, the pH change descend quickly at the5%salt concentration, reached the lowest value of3.79within10days, but it reached the4.49at7%salt concentration within20days. In contrast, the population of lactic acidbacteria increased rapidly at lower salinity, which reached the3.22×108cfu/ml at the10thday, the total populationof lactic acid bacteria is the100times lower compared to that of7%salinity. The experimental results can providethe theory identification for the understanding of microbial effects and quality control of pickled vegetablesprocessing at low salinity.