甘南牧区牦牛曲拉中乳酸菌的分离、鉴定及性能研究

为探究甘南牧区牦牛曲拉中乳酸菌的性能,本研究以甘肃省甘南地区藏族牧民家庭传统手工制作的牦牛乳曲拉样品为研究对象,以纯培养方法对曲拉中的乳酸菌分离鉴定,并研究曲拉中乳酸菌的性能。结果表明:从9份以自然条件发酵的牦牛曲拉中分离出97株乳酸菌,经过初步筛选得到6株乳酸菌菌株,通过16S rDNA分子鉴定,菌株Q1为嗜热链球菌(Streptococcus thermophilus),菌株Q2为耐久肠球菌(Enterococcus durans)、菌株G1、G2、G3、G4为瑞士乳杆菌(Lactobacillus helveticus);对6株乳酸菌进行性能研究表明,这6株菌凝乳时间在4~7 h之间,凝乳时的滴定酸度在73.42~89.38°T之间变化,酸乳冷藏期酸度增加了14.22~20.93 °T,活菌数含量均大于107 CFU/mL,黏度为5.42~7.84 Pa·s。研究结果可为乳酸菌的应用提供理论依据。

Isolation,Identification and Characterization of Lactic Acid Bacteria from Qula in Gannan

To investigate the performance of lactic acid bacteria in Qula in Gannan. In this study, the Qula sample, which was traditionally hand-made by Tibetan herders in Gannan, Gansu Province, was used as the research object. The lactic acid bacteria in the Qula were isolated and identified by pure culture method, and the performance of lactic acid bacteria was studied. The results showed that there were 97 strains of lactic acid bacteria were isolated from 9 Qula fermented under natural conditions. Six strains of lactic acid bacteria were obtained through preliminary screening. The strains were identified by 16S rDNA, strain Q1 was Streptococcus thermophilus, and strain Q2 was Enterococcus durans, strains G1, G2, G3, and G4 were Lactobacillus helveticus. The performance studies on 6 strains showed that the curd time of these 6 strains was between 4~7 h, the titratable acidity during curd was between 73.42~89.38°T, and the acidity of yogurt during the cold storage increased by 14.22 to 20.93°T, the viable counts were all greater than 107 CFU/mL, the viscosity was 5.42~7.84 Pa·s. The research results can provide a theoretical basis for the application of lactic acid bacteria.