副干酪乳杆菌L9的发酵性能驯化及其机理研究  

Studies on Fermentation Performance Domestication and Its Mechanism of Lactobacillus paracasei subsp. paracasei 9

作　　者：李转羽 刘松玲[2] 任发政[2] 金君华[1] 卢大新[1] 

机构地区：[1]北京农学院食品科学与工程学院农产品有害微生物及农残安全检测与控制北京市重点实验室食品质量与安全北京实验室,北京102206 [2]中国农业大学食品科学与营养工程学院,北京100083

出　　处：《中国食品学报》2016年第7期90-96,共7页Journal of Chinese Institute Of Food Science and Technology

基　　金：北京市自然科学基金青年项目(5154028)

摘　　要：副干酪乳杆菌L9分离自大理乳扇,虽具有润肠通便,预防肠炎的益生功能,但耐酸、耐氧性差限制了其产业应用。本研究通过低p H值和高氧浓度胁迫对L9进行耐酸、耐氧适应性驯化,获得高耐酸耐氧菌株。结果表明:驯化后菌株的凝乳时间为13 h,比原始菌株缩短14 h;7 d发酵后,驯化菌株发酵终点酸度达到(227.2±0.8)°T,比原始菌株高(52.0±3.1)°T,驯化菌株活菌数达到(7.9±0.7)lg(CFU/m L)。发酵乳贮藏试验表明,驯化菌株的滴定酸度在4℃贮藏中无显著变化,4℃贮藏15 d活菌数保持稳定。驯化菌株的β-半乳糖苷酶活性显著高于驯化前菌株,并与酶基因表达量结果一致。副干酪乳杆菌L9经驯化后菌株β-半乳糖苷酶的基因表达量高,酶活性强,菌株产酸能力强,产酸速度快,贮藏期具有良好的稳定性,具有较好的产业化潜力。Lactobacillus paracasei subsp. paracasei 9 was isolated from Rushan, a traditional fermented milk, in Dali, Yunnan, China. The strain has shown its physiologic functions such as relaxing bowel and prevention of inflammatory bowel disease et al. However, the acid and oxygen intolerance of the strain limited its application in industry. In this study, a strong stress-resistance strains was obtained by adaptive evolution of acid and oxygen resistent based on L9. After domesticated, the curd time of the domesticated strains is 13 h, which reduced 14 h compared with the original strain. After 7 day-fermentation, the titratable acidity of the skim milk fermented by the domesticated strains was higher（227.2°T ± 0.8°T vs 175.2°T ± 2.6 °T） than that of the original strains. The viable cells number of the domesticated strains was（7.9 ± 0.7） lg（CFU/m L） after 7 days fermentation. In 30 day storge experiments, the titratable acidity of the domesticated strains did not change significantly, the viable cells number of the domesticated strains maintained at（7.5± 0.8） lg（CFU/m L） during the first 15 day of storage. We found that beta-galactose glucoside enzyme activity in the domesticated strains was significantly higher than that in L9 during the fermentation, the changes was the same with the results of the real-time PCR. The domesticated strains showed well fermentation properties and storage stability, which is an efficient and potential yogurt starter strain for industry.

关 键 词：副干酪乳杆菌L9 驯化 发酵性能 驯化机理 

分 类 号：TS201.3[轻工技术与工程—食品科学]