| We lack of study that natural fermentation microflora dynamics for in-depth and systematic currently on the implemented compared with the international large-scale production of fermented vegetables microflora research, to provide an effective basis for selecting the inoculant to control sauerkraut fermentation, the bacteria succession and diversity were investigated during sauerkraut fermentation. The pH of the fermentation system decreased from 7.3 at Od to 4.1 at 8d of fermentation.Subsequently, the pH remained at approximately 4.0. Water soluble carbohydrate(WSC) content decreased from 11.4% dry matter(DM) to 3.9% DM during the first 18 days of fermentation.The highest nitrite value was 31.3mg/kg fresh matter(FM) at 6d.At 30d,the nitrite content descreasedto 4.8mg/kg FM. The concentrations of lactic acid and acetic acid in fermented juice were 6.7g/L and 0.6g/L, respectively.The bacteria detected in the fermentation system included Acinetobacter sp., Pseudomonas fragi, Klebsiella sp., Citrobacter sp., Betaproteobacteria sp. and lactic acid bacteria (LAB). The LAB contained Leuconostoc mesenteroides, Lactobacillus curvatus, Lactobacillus plantarum and Lactobacillus oligofermentans. At 6d, LAB comprised 63.8% of the bacterial population, with the heterofermentative LAB Leuconostoc mesenteroides comprising 32.9%. Subsequently, the proportion of LAB increased continuously. At 30d, all microorganisms were LAB. Lact. curvatus comprised 21.1% of the population at 6d,41.1% at 12d,and greater than 45% at 30d,dominating the fermentation process. For the first time,Lact. oligofermentans was found to be involved in thfermentation.The highest level of Lact.oligofermentans(21.1%) was detected at 12d.Based on the above results,thdominant microorganisms involved in suan-cai fermentation were LAB and Lact.Curvatus was the predominant microorganism in the fermentation.This study provides a foundation for screening the inoculant to control thsauerkraut fermentation.Second, we used the method of cultivation of northeast sauerkraut fermentation bacteria in the process of dynamic parsing. Results showed in the early phase of fermentation sauerkraut, the primry different dominant lactic acid bacteria fermentation,Separation of the bacteria including Leuconostoc,Enterococcus and Lactococcus aureus,and mainly in the late fermentation are the same type fermentation lactic acid bacteria, majority for the Lactobacillus, including Lactobacillus plantarum and Lactobacillus longer,Lactobacillus casei, Lactobacillus paracasei, Lactobacillus curvatus,etc. In the fermentation process also detect other general bacteria such as the Kluyvera sp. And Paenibacillus sp., these bacteria in existing pickled vegetable is not reported in literature. Thus, the lactic acid bacteria fermentation is the mainly process of the northeast sauerkraut fermentation, Cultivation of the lactic acid bacteria, provided the experimental material for subsequent experiments. The origin of the lactic acid bacteria as the sour pickled cabbage, for fermentation sauerkraut will than other sources of lactic acid bacteria has stronger adaptability.Finally, in the sour pickled cabbage source type with fermentation lactic acid bacteria and lactic acid bacteria fermentation alien, on the basis of the different types of fermentation lactic acid bacteria as inoculum of sauerkraut fermentation experiments. Respectively, set up to inoculation with type fermentation lactic acid bacteria in the fermentation system L. curvatus, lactic acid bacteria fermentation. Ln Mesenteroides and the combination of three kinds of fermentation process.The results showed that:(1) Compared with unvaccinated control processing, Inoculation treatment at the early stage of the fermentation of pH, soluble sugar, organic acids, nitrite, change is very severe, In concrete performance, compared to inoculation with pH decline is more rapid, Especially in the first 6 d fermentation was most evident difference (p<0.05); (2) The matching of soluble sugar consumes more, Cabbage initial soluble sugar content of 21% (dry matter basis), At 6d, after fermentation in soluble sugar content 15% the left and right sides, then sharply declined.at 18d, all processing of soluble sugar concentration less than 6%, at 30d, all processing soluble sugar change trend is rela tively slow, and is not significant difference between the groups (p<0.05); (3)We test the total number of bacteria in the fermentation system using the method of plate count microbial lactic acid bacteria, The results showed that the vaccination L. curvatus can improved the number of lactic acid bacteria obviously in the fermentation system in the early days, Especially the most significant to separate inoculation. This shows that due to vaccination, the ferment system into the state as early as possible, this state is more conducive to lactic acid bacteria proliferation. Due to the proliferation of lactic acid bacteria at the same time, a lot of acid, lead to other general bacteria proliferation significantly suppressed. Late fermentation, the lactic acid bacteria is dominated on the fermentation system, differences between the groups are not obvious. (4) In the organic acid, the lactic acid content was obvious increased using the vaccination L.curvatus treatment, Then the processing of mixed inoculation lactic acid content also increased significantly, At the end of the fermentation, lactic acid content change is not very big difference between the groups, Compared to other processing, mixed processing of lactic acid content slightly higher; (5) At 18d, the nitrite peak appeared in the fermentation system. Vaccination can effectively reduce nitrite content in the system, the inoculation treatment comparison, the processing of vaccination L.curvatus nitrite content was obviously lower than the other two inoculation treatment. Thus it can be seen, Vaccination can make earlier to enter a state of fermentation and make the development towards the direction of the controlled fermentation. |
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