发酵型核桃乳生产专用乳杆菌的选育

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。

Screening of Lactobacillus used for fermented walnut milk

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 rhamnosus, Lactobacillus paracasei, Weissella cibaria and Lactobacillus casei, respectively. The identified strains and laboratory preserved 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 increasing 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.