开菲尔发酵剂发酵特性研究

Fermentation properties of Kefir starters

以三种开菲尔发酵剂和一种普通酸奶菌种为发酵剂，制作成发酵乳。通过监测四种发酵剂发酵过程的pH值变化趋势，以及在4℃冷藏过程中酸度、pH值、黏度、乳酸菌活菌数、酵母菌、口感等指标，分析开菲尔发酵剂与普通酸奶发酵剂的发酵特点及其产品在保质期内特性变化。结果表明，与普通酸奶菌种相比，开菲尔发酵剂凝乳时间较长，发酵时间约为12-20h，在保质期内，酸度增长较为缓慢，黏度较低，乳酸菌活菌数较高，口感方面优于普通发酵剂酸奶。

Yogurt with three different Kefir starters and a common starter were made separately. The change ofpH during fermentation and the acidi- ty,viscosity, viable cells of lactic acid bacteria and yeast, and taste of the yogurt product at 4 ℃ were determined, to analyze the fermentation charac- teristics of Kefir common starters, and the character change during shelf life.The results indicated that the Kefir starterneed longer time forcoagulation, the fermentation time was 12-20 h. During shelf-life, the acidity of the yogurtfermented by Kefir changed slowly, the viscosity was lower, and the viable cells of lactic acid bacteria were more than that by commonyogurt. The taste of the yogurt fermented by Kefir was better than that by common starter.