传统藏式牦牛酸奶中优良乳酸菌筛选与产香性能分析

本研究旨在从我国传统发酵乳制品中筛选发酵性能和产香性能优良的乳酸菌。从四川阿坝藏族羌族自治州采集传统藏式牦牛酸奶样品并分离乳酸菌,经遗传稳定性、发酵时间及感官评价等初筛,并结合固相微萃取顶空气相色谱-质谱联用分析菌株产香性能进行复筛。结果显示,在26份样品中有5株发酵性能较优良的菌株,发酵时间为4.5~7.5 h,发酵终点酸度为74.0~78.4 °T,各菌株发酵乳感官评价良好。顶空气质结果发现菌株AB1504产生的乙醛(1.13 mg/L)、双乙酰(4.90 mg/L)等关键风味物质含量最高。研究结果表明从传统藏式牦牛酸奶中筛选到的嗜热链球菌AB1504发酵性能和产香性能优异,具有商业应用的潜力。

Separation of Excellent Lactic Acid Bacteria from Traditional Tibetan Yogurt and Its Fermentation Performance Analysis

This study aimed at screening lactic acid bacteria with excellent fermentation and aroma production performance from local traditional fermented dairy products. Traditional Tibetan yak yogurts samples were collected from the Aba Tibetan and Qiang Autonomous Prefecture,Sichuan province. Lactic acid bacteria were selected through genetic stability,fermentation time and sensory evaluation,and together with SPME-GC-MS for flavor. Totally 5 strains with excellent fermentation performance were screened from 26 yogurt samples,their fermentation time were 4.5~7.5 h,titration acidity were 74.0~78.4 °T,and sensory evaluation results were good. Results of SPME-GC-MS showed that the contents of key flavor substances such as acetaldehyde(1.13 mg/L)and diacetyl(4.90 mg/L)produced by strain AB1504 was the highest. The conclusion of this study was that Streptococcus thermophiles AB1504 screened from traditional Tibetan yak yogurts had nice fermentation performance and flavor,it has the potential for commercial application.