Biological Characterristics Of Lactic Acid Bacteria From Pickles And Study Of Fermentation Technology In Xining

The experiment mainly studies on the isolation,the biological properties and the immobilization of the Lactic acid bacteria that obtained from the pickles which were collected from the Xining city(West of Xining,East of Xining,South of Xining,North of Xining,Centre of Xining).In the paper four strains L-1,L-2,N-1 and N-2 were isolated from many sorts of pickles for their excellent characteristics in acid production and fermentation flavor.According to their characteristics of morphological,Physiological and biochemical and the test of the sugar fermentation,L-1 and L-2were identified as Leuconostoc mesenteroides subsp,mesenteroides. N-1 and N-2 were identified as Lactobacillus casei subsp,casei and Lactobacillus plantarum respectively.The growths of L-1 and L-2 were both prevented in the condition in which the pH was lower than 4.0 or the salty concentration was higher than 8%,while N-1 and N-2 could grow in the condition in which the pH was higher than 2.5 or the salty concentration was lower than 14%.The most appropriate temperature for the growth of L-1 and L-2 was 30℃,while that of N-1 and N-2 was 37℃.During the fermenting of cabbage inoculated with different compound bacteria as fermentation agent,the compounds contained L-1 produced acid more quickly than other compounds in the prophase of fermentation,while the compounds contained N-1 or N-2 produced acid more and more quickly in the anaphase of fermentation.The flavor of cabbage fermented with L-lsolely was best,that with the compounds of three strains were the next.Compound A(L-1) and compound B(L-1:N-1:N-2=1:1:2)were selected as excellent fermentation agent.When cabbage was fermented with compound A or compound B at 10℃, the fermentation was best.The nitrite contents of cabbage fermented with two compounds were lower than that of cabbage during spontaneous fermentation,and the nitrite content of cabbage inoculated with compound B was lower than that of compound A.At 4%salty concentration, 5%inoculation level and 1-3%sucrose concentration,the quality of cabbage fermented with L-1 solely was the best.When some apples were added during the cabbage fermenting,the pH decreased more quickly,and the total acid content increased.In the cabbage brine added with apple,the main organic acids whose intents were increase were malic acid and acetic acid,The sensory quality of fermented cabbage added apple were better than that of cabbage without apple.