泡菜纯种发酵优良乳酸菌的筛选及菌株特性研究

Isolation,identification and characteristics of lactic acid bacteria from pickles

从不同时期的新鲜泡菜汁中分离得到18株乳酸菌,筛选出2株发酵萝卜产酸能力强、风味好、亚硝酸盐含量低的菌株,经鉴定分别为肠膜明串珠菌肠膜亚种和戊糖乳杆菌。对这2株菌生长特性的测试结果表明:2株菌的生长温度范围较宽,最适生长温度均为37℃,最适生长pH值均为6~8,肠膜明串珠菌对酸度和盐度的耐受性比戊糖乳杆菌差,肠膜明串珠菌在pH值【4和盐浓度】8%时生长停滞,戊糖乳杆菌能够耐受pH值【3和盐浓度】8%的生长条件。肠膜明串珠菌和戊糖乳杆菌在MRS培养基中对初始亚硝酸盐的降解率分别为84.96%和93.17%。

18 Strains of lactic acid bacteria were isolated and identified from pickling cabbage and radish during various fermentation stages.Two strains were selected for having excellent characteristics in acid production,fermentation flavor and low nitrite concentration when pickling radish.These two strains were identified as Leuconostoc mesenteroides subsp.Mesenteroides and Lactobacillus pentosus.The characteristics of strains were also investigated.The strains could tolorate a wide range of temperature,the optimal growth situation for them were at 37℃ and at pH 6-8.Lactobacillus pentosus had better ability of acid and salty tolerance than Leuconostoc mesenteroides,Leuconostoc mesenteroides could grow when pH value is under 3 or content of salts is up to 8%,while Lactobacillus pentosus could not grow when pH value under 4 or content of salt up to 8%.Leuconostoc mesenteroides and Lactobacillus pentosus depleted 84.96% and 93.17% of the initial nitrite present in de Man,Rogosa and Sharpe broth cultural medium,respectively.