传统乳制品中乳酸菌的筛选及发酵性能研究

为获得优良发酵性能的乳酸菌，采用传统培养方法从传统发酵乳样品中分离乳酸菌，并将分离菌株制备发酵乳。通过考察发酵乳的感官品质筛选优良菌株，采用形态学观察及16S rDNA序列分析对筛选菌株进行鉴定；并对其生长性能、产酸性能及其制备发酵乳贮藏期内品质变化进行测定。结果显示，共分离得到67株乳酸菌，筛选出5株性能较佳的菌株（编号为C-1、Q164、Q165、Q166和Q167），均被鉴定为嗜热链球菌（Streptococcus thermophilus）。其中，菌株C-1生长性能和产酸性能最佳，该菌株制备的发酵乳奶香明显，口感细腻顺滑，感官评分最高（93.5分），30 ℃贮藏21 d后，酸度为86.0 °T，活菌数为7.2×103 CFU/g。综上，嗜热链球菌C-1具备优良发酵性能菌株的应用潜力。

Screening and fermentation performance of lactic acid bacteria in traditional dairy products

In order to obtain lactic acid bacteria with good fermentation performance, lactic acid bacteria were isolated from traditional fermented milk samples by traditional culture methods, and the fermented milk was prepared by isolated strains. The good strains were screened by investigating the sensory quality of fermented milk, and identified by morphology observation, 16S rDNA sequence analysis. The growth performance, acid production capacity and quality change of fermented milk during storage were determined. The results showed that a total of 67 strains of lactic acid bacteria were isolated, and 5 strains (numbered C-1, Q164, Q165, Q166 and Q167) with better performance were screened and all strains were identified as Streptococcus thermophilus. Among them, the strain C-1 had optimum growth performance and acid production capacity. The fermented milk prepared by strain C-15 had obvious milk flavor, smooth taste and the highest sensory evaluation score (93.5). After storage at 30 ℃ for 21 d, the acidity was 86.0 °T, and the viable count was 7.2×103 CFU/g. In conclusion, S. thermophilus C-1 had the application potential as a strain with excellent fermentation performance.