Microbial Community And Relationship With Nitrite Of Fermented Vegetable

Vegetable fermentation is a process dominated by microorganisms. Microbial species and quantity closely related with texture flavor and nutritional qualities of fermented food. Vegetables were rich in a variety of microbes that formed the unique microbial community structure in the fermentation system. Microorganism of vegetable fermentation included the lactic acid bacteria yeast and mold, etc. How the population growed in the fermentation system and the relationship with population of lactic acid bacteria and the effects of their interaction on vegetable fermentation were so far no system research both at home and abroad. The microbes in the fermentation process inevitablely producted nitrite in the process of the vegetable production and storage. However, the problem of nitrite content in the fermented vegetables exceed standard is the important problem limited vegetable fermentation industry. Therefore, this chapter researched fermented vegetable community change and microbiological assay related nitrite content change during vegetable fermentation process for providing theoretical basis that is Vegetable fermentation mechanism, the quality control and establishing low nitrite content process during the vegetable fermentation.During natural formation salt concentration acid producted by microoriganism fermentation lactic acid bacteria and auxiliary material were the main factor that had effect on microorganism community. Individual and group identification were prepared, community structure and function were analyzed in order to fully reveal changes in microbial community.By means of DGGE we identified bacteria and fungi community of fermented vegetables. The resulted showed the bacterial community of4%salt concentration fermented vegetables relatively abundant before and late fermenting progress, especially in the late fermenting, in fermentation medium species relatively were single, and fungal colony were relatively rich in the late and before fermentation; bacteria of6%salt concentration fermented vegetables were relatively stable, fungal community species were relatively single but biomass was high at the beginning of fermentation, species increased in the later of fermentation; bacteria community of8%salt concentration fermented vegetables were limited in the early stage of the fermentation and species were relatively abundant in the later of fermentation, fungi mainly existed in the early stage of the fermentation.Microbial community structure characteristics analysis showed that the bacterial species of4%salt concentration fermented vegetables were relatively rich in the late fermentation, fungal species were relatively rich in3d,5d,13d; bacterial community structure of6%salt concentration fermented vegetables were relatively stable throughout the fermentation period and far less than that of4%salt concentration fermented vegetables, fungal communities in early fermentation species were relatively single, but the content was rich; bacteria community of8%salt concentration fermented vegetables structure were the most stable of three kinds of salt concentration, fungi fermentation were the most abundant in3d.Trough the PCR-DGGE method combined with the BIOLOG, we analyse bacteria and fungi commubity change as the fermentation time during vegetable fermentation process, the results shows that in fermented vegetables bacteria system of4%salt concentration Pseudomonas sp.、 Serratia sp. Pantoea dispersa elt.Gamma proteobacteria and Staphylococcus sciuri existed, also fungi contained Wickerhamomyces anomalus、Candida sp. Meyerozyma guilliermondii; in fermented vegetables bacteria system of6%salt concentration Leuconostoc citreum、Leuconostoc mesenteroides、 Enterobacter sp.、Pantoea sp. and Saccharomyces cerevisiae、Meyerozyma guilliermondii、Debaryomyces hansenii、Pichia sorbitophila elt.fungi were founed; in fermented vegetables bacteria system of8%salt concentration Staphylococcus sciuri、Serratia sp.、Rahnella sp.、Candida glaebosa、Pichia sorbitophila、Wickerhamomyces anomalus and Kluyveromyces marxianus were exited. By BIOLOG microbial communities carbon source utilization of fermented vegetables showed that AWCD value of4%salt concentration fermented vegetables were a trend of steady rise before changing, AWCD value of6%salt concentration fermented vegetables was on the rise and AWCD value of8%salt concentration fermented vegetables irregularly changed; Microbial community of fermented vegetables diversity showed salt concentration and fermentation time had no effects on fermented vegetables microbial community richness and evenness (Shannon index), McIntosh index changed the most obvious in4%and6%salt concentration fermented vegetables, Simpson index changes showed4%and8%salt concentration had no significantly change, instead of6%salt concentration fermented vegetables.Though PCR-DGGE analysis method combined with nitrite change, this paper determined the relationship of dominant microorganism between nitrite formation and reduction. The results showed Pseudomonas sp.、 Pantoea dispersa、Candida sp.、Staphylococcus sciuri were raleted nitrite formation and serriatia sp.was raleted nitrite reduction in fermented vegetables bacteria system of4%salt concentration; in fermented vegetables bacteria system of6%salt concentration Enterobacteriaceae bacterium、 Leuconostoc citreum、Candida、saitoanaPichia sorbitophila related with nitrite formation and Pseudomonas sp. Sporidiobolus pararoseus related with nitrite reduction; in fermented vegetables bacteria system of8%salt concentration Debaryomyces occidentalis、Pichia sorbitophila.Pseudomonas sp. related with nitrite formation and serriatia sp.Staphylococcus sciuri related with nitrite reduction.