东北酸菜中产胞外多糖乳杆菌的分离筛选及其在酸乳中的应用

Isolation and screening of exopolysaccharide-producing lactobacilli from northeast sauerkraut and their applications in yoghurt

从东北酸菜中分离出97株乳杆菌菌株,并筛选出两株产酸快、产胞外多糖(EPS)的乳杆菌2号菌株和9号菌株。初步鉴定前者为干酪乳杆菌,后者为植物乳杆菌。在发酵剂(保加利亚乳杆菌和嗜热链球菌,LS)中混入等量的菌株2或9培养物(脱脂乳),所制备的酸乳中EPS质量浓度达34 mg/L,活菌总数可达2×108 mL-1以上。酸乳物性测定结果显示,产EPS菌株发酵的酸乳弹性好,相对粘度高,持水力强,乳清析出少。感官评定结果显示,与没有添加产EPS菌株发酵的酸乳相比,产EPS菌株LS+2与LS+9组合发酵酸乳风味分值较高,组织状态的分值差别较大,而酸度上没有显著差异。与物性测定结果一致。

97 Lactobacillus strains were isolated from traditional northeast sauerkraut, and 2 exopolysaccharide （EPS） - producing strains No.2 and No.9 were screened. Both strains gave good rates of acid production. Prehminary strain identification showed that strain No. 2 belonged to Lactobacillus casei, and strain No. 9 to LactobaciUus plantarum. Fermentation in skim milk with yoghurt culture added with equal amount of these 2 strains showed that strains No.2 and No.9 produced EPS of 34 mg/L, and had higher rate of producing acid with more than 2×10^8mL^-1 of total count. The measurement of physical properties revealed that the yogurt fermented with EPS-producing strains had better elasticity and viscosity, less whey syneresis, anti higher water-holding capacity, The organoleptic evaluation showed yogurt made with EPS-producing strains gave better flavor and texture, consistent with the measurement results of physical properties, though there were no obvious differences in acidity as compared with yogurt made with non-EPS producing strains.