Departamento de Bioquímica, Instituto de Química, Brazil.
J Dairy Sci. 2013 Jul;96(7):4149-59. doi: 10.3168/jds.2012-6263. Epub 2013 Apr 28.
The microbial community composition and chemical characteristics of a Brazilian milk kefir sample produced during its manufacturing and refrigerated storage were investigated by culture-dependent and -independent methods and HPLC. Lactococcus lactis ssp. cremoris and ssp. lactis, Leuconostoc mesenteroides, Acetobacter lovaniensis, and Saccharomyces cerevisiae were isolated, whereas the detected bands on denaturing gel gradient electrophoresis corresponded to Lactobacillus kefiranofaciens, Lactobacillus kefiri, Lactobacillus parakefiri, and S. cerevisiae. After fermentation, lactic acid bacteria were present at levels of 10 log units, whereas acetic acid bacteria and yeast were present at levels of 7.8 and 6 log units, respectively. The lactic acid bacteria and yeast counts remained constant, whereas acetic acid bacteria counts decreased to 7.2 log units during storage. From fermentation to final storage, the pH, lactose content and citric acid of the kefir beverage decreased, followed by an increase in the concentrations of glucose, galactose, ethanol, and lactic, acetic, butyric, and propionic acids. These microbiological and chemical characteristics contribute to the unique taste and aroma of kefir. This research may serve as a basis for the future industrial production of this beverage in Brazil.
采用培养依赖和独立方法以及 HPLC 对巴西牛奶酒发酵和冷藏过程中的微生物群落组成和化学特性进行了研究。分离出乳球菌乳亚种和乳亚种、肠膜明串珠菌、嗜乙酰乙酸杆菌和酿酒酵母，而变性凝胶梯度电泳上检测到的条带则对应于发酵乳杆菌、开菲尔乳杆菌、副干酪乳杆菌和酿酒酵母。发酵后，乳酸菌的含量达到 10 个对数单位，而醋酸菌和酵母的含量分别为 7.8 和 6 个对数单位。在储存过程中，乳酸菌和酵母的数量保持不变，而醋酸菌的数量下降到 7.2 个对数单位。从发酵到最终储存，牛奶酒的 pH 值、乳糖含量和柠檬酸降低，随后葡萄糖、半乳糖、乙醇以及乳酸、醋酸、丁酸和丙酸的浓度增加。这些微生物学和化学特性有助于牛奶酒独特的口感和香气。本研究可为巴西未来的这种饮料的工业生产提供依据。
