酵素源乳酸菌的益生功能及抑菌特性评价

为筛选到发酵性能稳定且高效的功能性菌株，以韶关紫背桃源生产的酵素中分离出的12株乳酸菌为试验菌株，测定其益生特性。分别对12株乳酸菌进行了自聚集性、耐酸性，以及对胆盐、胃蛋白酶、胰蛋白酶与抗生素的耐受性和对肠道致病菌的拮抗作用实验，结果表明：12株受试乳酸菌均表现出良好的自聚集性；除XZJ07外，其他11株菌株在pH值为2.5的模拟胃液中培养3 h存活率仍达75%以上；在人工模拟胃液以及肠液中对胃蛋白酶和胰蛋白酶孵育2、3 h存活率仍超过75%；在含有胆盐浓度为3 g/L MRS培养基中培养3 h后，活菌数仍达106 CFU/mL，另外，受试菌株对金黄色葡萄球菌、大肠杆菌均有一定的抑制作用，对大肠杆菌抑菌圈直径均大于15 mm，对金黄色葡萄球菌抑菌圈直径均大于17 mm；受试菌株对氨苄青霉素敏感，对四环素、红霉素、土霉素较为耐受。研究结果预示着受试菌株具有作为优质益生性发酵剂的潜在能力。

Evaluation of Probiotic and Antibacterial Properties of Lactic Acid Bacteria Derived from Fermented Fruit Broth

The probiotic properties of 12 lactic acid bacteria strains isolated from the enzymes produced in purple peaches from Shaoguan were investigated to screen efficient functional strains with stable fermentation performances. Self-aggregation; acid, bile salt, pepsin, trypsin, and antibiotic resistance; and antagonism against intestinal pathogens were tested. The results showed that the 12 lactic acid bacteria strains demonstrated notable self-aggregation. The survival rate of all strains except XZJ07 was >75% when cultured in simulated gastric juice at pH 2.5 for 3 h. The survival rate of the strains under pepsin and trypsin stresses in artificial gastric juice and intestinal juice was >75% after 2~3 h. After cultivation in 0.3% bile salt for 3 h, the viable count was up to 106 CFU/mL. The tested strains also had an inhibitory effect on Staphylococcus aureus and Escherichia coli. The diameter of their inhibition zone against Escherichia coli and Staphylococcus aureus was greater than 15 and 17 mm, respectively. The tested strains were sensitive to ampicillin, but tolerant to tetracycline, erythromycin, and oxytetracycline. These results indicate that the tested strains may serve as high-quality probiotic fermentation agents.