The Identification,basic Research And Application Study Of Lactobacillus Isolated From Banana Plants

Through analyzing the diversity of lactobacillus on the plants of Musa nana Lour and expanding the plant source of lactobacillus,it can provide the plant source lactobacillus for the silage fermentation industry and the food fermentation industry in the future.The study uses the method which combines the method of classical lactobacillus screening and the method of molecular biology to separate and identify Lactic acid bacteria on banana plants.And then the study aims to carry out physiological and biochemical test,the determination test of growth rate and the determination test of acid production rate.According to the above results of tests,the research can select the representative strain which will accept sequencing,homology analysis and the construction of a phylogenetic tree;Inhibition tests were used in foods such as Escherichia coli,Salmonella,Bacillus bacillus,and Listeria monocytogenes.The results showed that there are totally 84 strains of lactic acid bacteria which are screened from six parts of banana plants.What's more,9 representative strains includes 7 Lactobacillus plantarum(WFr6-4?WSt6-4?WL7-3?BH6-2?BG4-2?BY6-2 and Bg4-3),1 Lactobacillus pentosus(WF15-3)and 1 Enterococcus casseliflavus(WR7-1).Thus,Lactobacillus plantarum on the banana plants was the dominant bacteria,and the bacteriostatic effect was better.Two Lactobacillus plantarum strains and one Lactobacillus casei strain were used to ferment banana and enoki mushroom together.Response surface method(RSM)was used to optimize the fermentation process.According to the sensory evaluation and the content of lactic acid,the optimized fermentation condition was identified:banana juice/enoki mushroom juice=4:1,4%starter culture,5.5%saccharose,and 20 h fermentation time at 37?.The predicted value of the sensory evaluation was 91.86 and that of the lactic acid content was 7.30 g/L.The true value of sensory evaluation was 93 and that of the lactic acid content was 7.21 g/L,indicating the efficacy of RSM in optimizing the fermentation process.In addition,an orthogonal test with the sensory evaluation as a criterion was used to optimize the stability of the fermented product.The best technological parameter of the stability of the fermented beverage was A2B2C3,i.e.the content of CMC-Na,xanthan gum and carrageenan were 0.15%,0.3%and 0.4%,respectively.Furthermore,CMC-Na affected the sensory evaluation more than xanthan gum,which affected more than carrageenan.