摘要肠球菌具有多种益生作用，但由于消化道中胃液、胆汁等物质会对菌体产生不利影响，从而导致益生作用的发挥。因此提高其稳定性研究具有一定的现实意义。本课题从本课题组筛选得到的性能优良的肠球菌孔雀③出发，利用微胶囊技术提高其稳定性。以植物蛋白大豆分离蛋白与海藻酸钠的混合物为包埋壁材，对肠球菌进行包埋，对其在低模拟胃液稳定性、模拟胆汁稳定性、储存稳定性和释放性性能进行研究。结果表明，模拟胃液中，120 min后包埋菌体活菌数仍有6 LogCFU/g；0.5与1.0 %的胆汁溶液中孵化120 min后，包埋菌体活菌数从10 log CFU/g分别降到8.8 LogCFU/g和8.4 LogCFU/g；包埋肠球菌能在90 min内完全释放；储存稳定性实验中，包埋肠球菌活菌数均比游离菌体高2 LogCFU/g左右。由此可知，以海藻酸钠-大豆分离蛋白为壁材的微胶囊技术是一种提高肠球菌稳定性的好技术。58256

Abstract Enterococcus can provide beneficial effects on organism. However, there are still many challenges to overcome because enterococcus is very sensitive to gastrointestinal environments, such as gastric juice, bile etc. In this paper, a new encapsulation carrier was applied in order to improve the survival of enterococcus.Enterococcus was encapsulated in alginate-soybean protein microspheres. The tolerance of encapsulated enterococcus to adverse environments such as low pH, high concentration of bile salt and storage stability, was investigated. Release characteristic of encapsulated enterococcus in simulated intestine fluid was also studied. The results showed that encapsulation could improve the tolerance of enterococcus to adverse environments. The viability of encapsulated enterococcus in 0.50 % and 1.0 % bile salt solution was reduced from 10 LogCFU/g microspheres to 8.8 and 8.4 LogCFU/g microspheres after 2 h incubation, respectively. Entnterococcus encapsulated in alginate–soybean microspheres could be completely released in 90 min. The viability of encapsulated entnterococcus could be kept more than 6 LogCFU/g after 120 min incubation in simulated gastrointestinal fluid pH 2.0. These studies demonstrated that encapsulation of enterococcus in alginate–soybean protein microspheres is an effective protection technique against adverse environment.

毕业论文关键词：包埋； 肠球菌； 筛选； 益生菌

Keyword: Encapsulation； enterococcus； screening； probiotic

目    录

1.微胶囊技术概述 4

1.1微胶囊技术简介 4

1.2微胶囊壁材研究 4

2.实验材料 5

3.实验方法 5

3.1菌种的筛选 5

3.2益生菌稳定性的提升 5

3.2.1菌种活化与菌悬液制备 6

3.2.2壁材配比与粒径大小试验 6

3.2.3肠球菌微胶囊制备 6

3.2.4游离与包埋肠球菌的存活率计算 6

3.3活性测试 6

3.3.1肠球菌模拟胃液稳定性 6

3.3.2肠球菌模拟胆汁稳定性 6

3.3.3肠球菌释放曲线 7

3.3.4肠球菌储藏稳定性 7

3.4数据处理 7

4.结果与讨论 7

4.1肠球菌筛选结果 8

4.2壁材配比与粒径大小实验结果