海洋寡糖益生菌微胶囊的制备和体外评估及其对动物肠道菌群的调节作用

为解决益生菌不耐低pH值、不耐氧的缺点，采用微胶囊包埋技术，以海藻酸钠为壁材用乳化法制备长双歧杆菌藻酸盐微胶囊。将基础藻酸盐微胶囊外包壳寡糖（chitosan oligosaccharides，COS）或在藻酸盐壁材中添加藻酸盐寡糖（alginate oligosaccharides，AOS）分别制备两种海洋寡糖微胶囊：COS-微胶囊和AOS-COS-微胶囊。体外实验表明：两种海洋寡糖微胶囊均可以显著提高长双歧杆菌在模拟消化液处理后或在4 ℃贮藏期内的存活率。AOS-COS-微胶囊在模拟胃液处理后仍能保持106 CFU/g以上的活菌数。在连续的模拟消化液处理后，AOS-COS-微胶囊中的活菌量达到基础微胶囊中的约1 000 倍。两种海洋寡糖微胶囊在4 ℃贮藏28 d后仍均能保持108 CFU/g以上的活菌数。体内实验表明：相比较未包埋的长双歧杆菌或基础微胶囊，海洋寡糖微胶囊可以显著提高动物肠道菌群中益生菌的含量，同时降低条件致病菌的含量，具有最佳的调节肠道菌群效果。因此，海洋寡糖益生菌微胶囊产品将是一种有巨大应用前景的新型功能性益生菌食品。

Preparation and In Vitro Evaluation of Marine Oligosaccharide Coated Microcapsules Containing Probiotics and Their Regulatory Effect on Animal Intestinal Flora

In order to solve the intolerance of probiotics to low pH and oxygen, Bifidobacterium longum was microencapsulated using alginate as the wall material in this study. Microcapsules were prepared with alginate alone or with alginate + alginate oligosaccharides (AOS) by emulsification method and then coated with chitosan oligosaccharides (COS) yielding COS-microcapsules and AOS-COS-microcapsules, respectively. In vitro experiments showed that the two marine oligosaccharide coated microcapsules could greatly improve the survival rate of B. longum in simulated digestive juice or during storage at 4 ℃. AOS-COS-microcapsules could maintain a viable cell count of more than 106 CFU/g after simulated gastric digestion. After simulated gastrointestinal digestion, the viable cell count of AOS-COS-microcapsules was about 1 000 times as high as that of the uncoated microcapsules. The two marine oligosaccharide coated microcapsules could maintain a viable cell count of greater than 108 CFU/g after storage for 28 days at 4 ℃. In vivo experiments showed that compared with free B. longum and the bare microcapsules, the coated microcapsules could significantly increase the content of probiotics and reduce the content of opportunistic pathogenic bacteria, and were more effective in regulating the intestinal flora. Therefore, marine oligosaccharide coated microcapsules containing probiotics have a great potential as a new type of functional food.