Reserch On The Directed Vat Set Stater Of Sauerkraut

In this experiment,20 strains were isolated and purified from 10 Chinese sauerkraut,which were preliminarily identified as lactic acid bacteria by morphological and physiological-biochemical tests.Through nitrite degradation test,Bacillus 2(1)and Cocci 3-2(1),which have the highest ability to degrade nitrite,were selected for further experiments.Through the identification and homology analysis of 16 S r RNA gene,2(1)was identified as Lactobacillus plantarum,3-2(1)was identified as Enterococcus durans,the above two strains were selected as the starter for fermentation.The optimum incubation time for L.plantarum 2(1)was 6 h to 14 h,for E.durans 3-2(1)was 4 h to 14 h.3%,5%,8% and 10% concentration of protectant mixed with above two strains,were added into the directed vat set separately,by comparing the loss rate of viable bacteria before and after lyophilization,the optimum ratio of protective agent and water was determined to be 3%.The best processing technology was obtained by single factor experiments,the condition was set to 4 ?or 25 ?storage,using tap water or plain boiled water,confirmed that the best storage temperature of directed vat set was 25?,and the best water for pickling was plain boiled water.The orthogonal test showed that the ratio of strain had a significant effect on nitrite content in sauerkraut,The optimum fermentation conditions were as follows:the ratio of L.plantarum 2(1)to E.durans 3-2(1)was 1:2,the best salt concentration was 6%,and the best pickling temperature was 4?.Sauerkraut reached maturity on the fourth day under this fermentation condition,and the nitrite content was in accordance with the national standard,the most probable Escherichia coli number per milliliter was less than 3.0.This research provided experimental data and strain resources for the starter of sauerkraut.