低聚木糖复配冻干保护剂的优化及其对双歧杆菌微胶囊性能的影响

为提高双歧杆菌在微胶囊制备过程中以及人体胃肠系统中的存活率，本文通过单因素和正交试验确定了低聚木糖复配冻干保护剂的最佳比例，同时考察了保护剂的加入对微胶囊性能的影响。结果表明，保护剂最佳配比为低聚木糖4.0%、甘油2.0%、谷氨酸钠1.0%，由此制备的双歧杆菌微胶囊包埋率和冻干存活率分别为81.5%±0.7%与88.1%±0.3%，与未添加组相比，其最终活菌负载率提高了约21.6%；添加复配保护剂的微胶囊表面更加平整致密，经模拟胃液处理2 h，双歧杆菌存活率为65.9%，相对于对照组提高了约15.3%；在人工肠液中，添加入保护剂的微胶囊的活菌释放量明显高于未添加保护剂组；在4 ℃和25 ℃贮存35 d后，添加复配保护剂的微胶囊活菌量分别为8.1 lg CFU/g和7.0 lg CFU/g，显著高于未添加保护剂的微胶囊(P<0.05)。因此，添加低聚木糖复配的冻干保护剂可以有效提高双歧杆菌微胶囊对不良环境的抗性。

Optimization of Cryoprotectants Complexed with Xylo-oligosaccharides and Its Effects on the Properties of Bifidobacterium Microcapsules

In order to increase the viability of Bifidobacterium in microcapsules formation process and in human gastrointestinal system, the optimized additive amount of cryoprotectants complexed with xylo-oligosaccharides was determined by single-factor and orthogonal experimental test. The influences of optimal cryoprotectants on the properties of microcapsules were also studied in this paper. The results showed that the optimized cryoprotectants composition was 4% of xylo-oligosaccharides, 2% of glycerol, and 1% of sodium glutamate, which could achieve 81.5%±0.7% of embedding rate and 88.1%±0.3% of freeze-drying survival rate for Bifidobacterium in microcapsules. Compared to the blank group, the cryoprotectants adding group was increased 21.6% of final active bacteria loading rate. In addition, the surface of the microcapsules added with the cryoprotectants was smoother and denser than the blank group. In simulation human gastrointestinal system, after digested 2 h in artificial gastric juice, there were 65.9% of Bifidobacterium survived in cryoprotectants group, which increased 15.3% of survival rate comparing with blank group. The cryoprotectants also significantly improved the probiotic release from microcapsules in artificial intestinal fluid. After storage at 4 and 25 ℃ for 35 days, the number of survival Bifidobacterium in the microcapsules added with the cryoprotectants were 8.1 lg CFU/g and 7.0 lg CFU/g, which significantly (P<0.05) higher than the blank. Therefore, adding cryoprotectants complexed with xylo-oligosaccharides could improve the resistance of Bifidobacterium in adverse environments.