发酵型核桃乳生产专用乳杆菌的选育

Screening of Lactobacillus used for fermented walnut milk

从发酵面包、白芥丝、泡菜、酸菜中分离到14株乳杆菌,经核桃乳发酵产酸特性初筛,确定菌株L5、L7、L8及L12适合核桃乳发酵。通过菌落形态、菌体形态和16S rRNA基因序列分析,确定4株菌分别为鼠李糖乳杆菌(Lactobacillus rhamnosus)、副干酪乳杆菌(Lactobacillus paracasei)、食窦魏斯氏菌(Weissella cibaria)干酪乳杆菌(Lactobacillus casei)。将上述菌株与实验室保存的嗜热链球菌SA进行核桃乳发酵实验,感官评分分别为78分、95分、83分和82分;4个发酵核桃乳中9种氨基酸含量均有不同程度提高,其中菌株L7发酵产品的氨基酸含量增幅最大,由0.67%增至1.60%。因此副干酪乳杆菌L7更适合发酵型核桃乳的生产。

14 strains of Lactobacillus were isolated from fermented bread, white mustard silk, pickles and Chinese sauerkraut. After preliminary screening based on acid- producing characteristics in walnut milk fermentation, 4 strains （strains L5, L7, L8 and L12） which were suitable for walnut milk fermentation were determined. By colonial morphology, mycelial morphology and 16S rRNA gene sequence analysis, 4 strains were identified as Lactobacillus rhatrmosus, Lactobacillus paracasei, Weissella cibaria and Lactobacillus casei, respectively. The identified strains and laboratory pre- served Streptococcus thermophilus SA were tested for the fermentation of walnut milk. The sensory evaluation score of fermented walnut milk were 78, 95, 83 and 82, respectively. 9 kinds of amino acids contents in 4 fermented walnut milks were increased in different degrees, in which the increas- ing amplitude of amino acid content in the product fermented by strain L7 was the highest and increased from 0.67% to 1.60%. L. paracasei L7 was more suitable for the production of fermented walnut milk.