酸乳发酵中优良共生酵母菌的筛选

为了筛选酸乳发酵中与保加利亚乳杆菌优良共生的酵母菌。以保加利亚乳杆菌单菌发酵酸乳为对照,将前期从新疆、西藏和青海等地区传统自制乳制品中分离的27株酵母菌株分别和保加利亚乳杆菌混菌发酵制备酸乳,通过比较凝乳时间、感官特性、质地特性、后酸度、粘度、持水力、乙醛和双乙酰含量等特征,筛选酸乳发酵中与保加利亚乳杆菌优良共生的酵母菌株;基于26S D1/D2区和ITS1序列鉴定菌株。结果显示:27株酵母菌株均没有明显促进凝乳作用,9株菌混菌发酵酸乳在感官评价得分较高(80分以上),其中菌株"XS1"混菌发酵的酸乳质地特性表现优良,后酸度为4°T、持水力为100%、双乙酰含量12.65 μg/mL、乙醛含量7.19%,分子生物学方法鉴定"XS1"为马克斯克鲁维酵母(Kluyveromyces marxianus)。结论:菌株"XS1"可以为开发新型酸乳提供参考。

Screening of symbiotic yeast in yoghurt fermentation

To screen yeast strains which are excellent symbiosis with Lactobacillus delbrueckii in yoghourt fermentation in this paper,the yoghourts were fermented with Lactobacillus delbrueckii mixed with 27 yeast strains isolated from the traditional dairy products collected from Xinjiang, Tibet, Qinghai and other regions. Then, these yoghourts were compared with the yoghurt fermented only with Lactobacillus delbrueckii on the milk curd time,sensory evaluation,texture,titration acidity,viscosity,the content of diacetyl and acetaldehyde to screen symbiotic yeast excellent performance in yoghourt fermentation. The excellent symbiotic yeast strains were identified based on 26S D1/D2 region and ITS1 sequence.The results showed that 27 strains of yeast were not significantly different on the milk curd time.But the yoghourts co-fermented with 9 yeast strains had scores at more than 80 in sensory evaluation.Among them,the yoghourts co-fermented with "XS1" had excellent performance in texture, titration acidity at 4° T, viscosity at 100%, the content of diacetyl at 12.65 μg/mL and acetaldehyde at 7.19%. The strain "XS1" was classified as Kluyveromyces marxianus with molecular biology methods.The strain "XS1" could provide reference for the development of new yoghurt.