传统乳制品来源乳酸菌的发酵特性及其在酸奶中的应用

Fermentation properties of Lactic acid bacteria from traditional dairy products and application in yogurt

对从传统乳制品中分离出的4株保加利亚乳杆菌和4株嗜热链球菌发酵特性及应用进行研究。利用脱脂乳进行培养,以发酵时间、风味物质及贮藏过程中的p H、滴定酸度、持水力、粘度变化为指标,研究单菌株的发酵性能。进一步对较优发酵性能菌株复配,考察不同接种比例时酸奶的酸度、粘度、风味、感官等指标,研究其在酸奶中的应用。结果表明,保加利亚乳杆菌Lb.YNF-5和嗜热链球菌St.GST-6具有良好的发酵性能。通过对此两株菌进一步复配,最终确定当保加利亚乳杆菌(Lb.YNF-5):嗜热链球菌(St.GST-6)配比为1∶1时,酸奶产品品质最佳,发酵时间为5.8 h,粘度为7186.47 m Pa·s,感官评价得分为76分。本研究综合表明,菌株Lb.YNF-5和St.GST-6具有开发优良酸奶发酵剂的潜在价值。

In this study,four strains of L.bulgaricus and four strains of S.thermophilus ,which were isolated from traditional dairy products ,were investigated for the fermentation parameters and application in yogurt, Strains were fermented by skim milk culture medium.Fermentation properties such as fermentation time, main flavor substance, pH, titration acidity, viscosity and water holding capacity were determined. Strains with superior fermentation performance were further fermented with different ratios.Fermentation parameters and sensopy parameters of the fermented milk were assayed.The results showed that Lb.YNF-5 and St.GST-6 were selected as the strains with superior fermentation performance.The best ratio was Lb.YNF-5：StGST-6 = 1： 1, giving the best quality of yogurt with fermentation time of 5.8 h, viscosity of 7186.47 mPa-s,the sensory evaluation score of 76 points.In summary,Lb.YNF-5 and St.GST-6 could be good candidates potential of application as yoghurt starter cultures.