一株产细菌素植物乳杆菌高密度发酵培养基的筛选及其在酸奶中的应用

Screening of High Cell Density Fermentation Medium of a Bacteriocin-producing Lactobacillus plantarum and Its Application in Yoghurt

目的:优化用于高密度发酵产细菌素的植物乳杆菌KLDS 1.0391的经济有效培养基,旨在生产具有益生作用的辅助发酵剂。方法:以发酵液中活菌数量和抑菌效果为指标,比较不同水解度的脱脂乳粉、乳清粉、麦麸,以及玉米浆粉的发酵效果,制备冻干形式的植物乳杆菌直投式发酵剂,将其添加至酸奶中,评价其对酸奶发酵时间、pH、滴定酸度、粘度和感官评价的影响,进而确定其在酸奶中应用的可行性。结果:确定脱脂乳粉、乳清粉和麦麸培养基的最佳水解度分别为15%、15%和20%;植物乳杆菌KLDS 1.0391在玉米浆粉培养基中获得的发酵效果最佳,活菌数量达到9.53 lg CFU/mL,抑菌圈直径达到12.69 mm。植物乳杆菌直投式菌种的添加对酸奶发酵时间和感官评价无显著影响(P>0.05),酸奶粘度下降,但可以缓解酸奶的后酸化程度。通过优化得到植物乳杆菌KLDS 1.0391高密度发酵的廉价培养基为:4%玉米浆粉,同时补充2%葡萄糖和0.1%Tween-80。结论:制得的植物乳杆菌直投式发酵剂可应用于酸奶生产中。

Objective:To optimize a cost-effective medium for high cell density fermentation of Lactobacillus plantarum KLDS 1.0391 and produce probiotic direct-in-vat starter culture.Methods:The number of viable bacteria and antimicrobial activity of fermentation broth were determined,fermentation effects of skim milk powder,whey powder,wheat bran with different hydrolysis degrees and corn steep powder were compared.The direct-feeding starter of Lactobacillus plantarum in freeze-dried form was prepared and added to yogurt to evaluate its effects on fermentation time,pH,titration acidity,viscosity and sensory evaluation,and determine its feasibility in yogurt application.Results:The optimum hydrolysis degrees of skim milk powder,whey powder and wheat bran were determined to be 15%,15%and 20%,respectively.The best fermentation results were obtained when Lactobacillus plantarum KLDS 1.0391 was cultured in corn steep powder medium,with the number of viable bacteria achieved 9.53 lg CFU/mL and the diameter of bacteriostatic circle achieved 12.69 mm.The addition of direct-in-vat starter culture of Lactobacillus plantarum exhibited no significant effect on the fermentation time and sensory evaluation of yogurt(P>0.05),while the viscosity of yogurt decreased and the post-acidification of yogurt could be delayed.Conclusion:The low-cost natural medium for high cell density fermentation of Lactobacillus plantarum KLDS 1.0391 was obtained in this study,its components were 4%corn steep powder,supplemented with 2%glucose and 0.1%Tween-80.Conclusion:The direct-in-vat starter culture of Lactobacillus plantarum produced in this study could be used in yogurt production.