优良“老酸奶”发酵剂组合的筛选

Screening the good set-style yogurt combined starter culture

为了筛选出优良的酸奶发酵剂,根据菌株的稳定性、发酵活力、凝乳时间等指标对23菌株(其中有13株球菌与10株杆菌)进行初步筛选,获得13株具有优良发酵特性的菌株(其中有7株球菌与6株杆菌)。根据单菌株发酵实验结果,按菌种性能互补原则将各球菌与杆菌复配,进行28个组合发酵实验,测定发酵速度、质构、乳清析出以及后酸化等指标。最终筛选出球菌S1、S4与杆菌L2,此组合与目前商业化直投发酵剂比具有发酵前期产酸速度快、发酵时间短的优点,而且具有天然的发酵香气,乳清析出量很少,适用于直投式发酵剂的生产。

To screen starter cultures for set-style yogurt production, the fermentation characteristics of 23 lactic acid bacteria strains （13 streptococci and 10 lactobadlh） were studied. By comparing the stability, activity and curd time of the 23 strains, 13 strains （7 streptococci and 6 lactobadlh） were screened out preliminary. According to the bacteria prepotent compensate principle, different strains were combined each other, and combined strains were evaluated according to the characteristics of fermented milk such as lactic acid productivity, texture profile analysis, quan- tity of whey and the acidification of the fermented milk during storage etc. The best combination strains were $1, $4 and L2. This combination produces acid quickly at the beginning of fermentation and has litde whey, good flavor which has the potential to be used as the direct vet starter.