Isolation And Identification Of The Lactobacillus Plantarum Strain From Pickles And Its Application

Lactobacillus Plantarum belongs to the Lactobacillus genus of Lactic Acid Bacteria andthe human gastrointestinal tract probiotics, which is positive to Gram staining and the normalbacterial flora of the advantages. It can produce acid metabolites, hydrogen peroxide, diacetyl,bacteriocins and other substances that can inhibit pathogenic and spoilage bacteria,It is onereason that why probiotics have special health care functions. Besides the above features,Lactobacillus has very wide applications in food, especially in the role of acid fermented food,such as pickles’production.In this study, one lactic acid bacteria is isolated from commercially available pickles andit is identified as Lactobacillus by its morphology, cultural characteristics, physiological andbiochemical as well as qualitative aspects of lactic acid. Also with a deep study of theirgrowth and culture conditions, medium optimization, proliferation factors affecting its growthand reproduction. The best optimization of culture conditions and culture medium can bedetermined through an orthogonal experiment. The results show:1. The Lactobacillus plantarum’s growth and change of pH cave can be obtained byexperiment and Lactobacillus logarithmic stage is18h based on the growth curve.2. The optimization of culture conditions orthogonal test showed: The primary andsecondary is significantly A=C> B (The medium three factors: A: culture temperature, B:culture time and C: the initial pH), means the culture temperature and the pH of the mediumas significant This may be due to temperature effects the growth and metabolism of lactic acidbacteria, also affects the activity of the intracellular enzyme accordingly. The bestcombination is: the culture temperature is34oC, the culture time is22h, and the initial pH ofthe medium is6.5.3. The medium optimization orthogonal test shows that: The primary and secondary issignificantly B> C> A (A: three kinds of nitrogen ratio, B: three kinds of carbon ratio and C:the amount of yeast extract (%)). The best combined is three nitrogen ratio is1:2:1, andcarbon ratio is1:1:2, the amount of yeast extract is0.7%.4. The optimal orthogonal test of multiplication factor shows that: The primary andsecondary is significantly B> C> A (A: carrot juice. B: tomato juice. C: amino acids (0.05%)).The best combination is carrot juice dosage is5%, tomatoes is10%and choose Cystine(cysteine) as amino acids with0.05%.5. The optimum fermentation parameters of pickles Assorted by Lactobacillus Plantarumare: salt plus7%, glucose plus5%,0.2%inoculation, fermentation temperature34℃. 6. Pure fermentation has a better sensory quality than natural fermentation. Reducing rateof pH in pure fermented is faster than natural fermentation and faster in acid production. Thenitrite content of both has no difference significantly. Production of microbial indicators infermentation (the total number of bacteria, fungi) is better than the natural fermentation.