研究了海藻酸钠（ALG）-魔芋葡甘聚糖（KGM）微胶囊对嗜酸乳杆菌CGMCC1.2686的保护效果，特别是KGM分子量对微胶囊保护乳酸菌效果的影响。利用酶法制备不同分子量KGM，将不同分子量KGM与ALG复配，采用内源乳化法制备乳酸菌微胶囊，测定微胶囊物理特性和乳酸菌保护效果各指标。结果发现，ALG与KGM复配，增大了微胶囊粒径（由309 μm至412~452 μm），且微胶囊粒径随KGM分子量的增加而增加；复配微胶囊机械强度、粘弹性、乳酸菌包埋率、模拟胃液菌体存活率及胆盐菌体存活率均大于ALG微胶囊，其中中等分子量KGM-ALG微胶囊在上述五项指标中均表现最优；回归分析表明，模拟胃液菌体存活率和胆盐菌体存活率与ALG-KGM微胶囊机械强度正相关。因而，ALG与KGM复配提高了微胶囊对乳酸菌的保护效果，同时该保护效果与KGM分子量大小相关。

In this study, the physical properties of alginate (ALG)-konjac glucomannan (KGM) microcapsules and their protective effect on Lactobacillus acidophilus CGMCC1.2686 (LAB), particularly the impact of KGM molecular weight were investigated. KGM fractions with different molecular weights were prepared by enzymatic degradation. Mixtures of KGM with different molecular weights and ALG were used as composite wall material to encapsulate LAB via the emulsification/internal gelation method. The capsule mean size increased from 309 μm to between 412 and 452 μm after the addition of KGM to ALG and the mean diameter increased with increasing molecular weight of KGM. Compared to ALG microcapsules, all ALG-KGM microcapsules showed greater mechanical strength, viscoelasticity, encapsulation yield, and LAB survival rate in simulated gastric juice (SGJ) and bile salts (BS). Additionally, microcapsules prepared from intermediate-molecular weight KGM exhibited the highest values for these five indices. Regression analysis showed that survival rates in SGJ and BS positively correlated with mechanical strength of the ALG-KGM composite microcapsules. In conclusion, mixing ALG and KGM enhanced the protective effect of microcapsules on LAB, which in turn, was correlated with KGM molecular weight.

湖北省自然科学基金面上项目（2012FFB00705）；湖北省教育厅科学研究计划项目（Q20141401）；湖北工业大学博士科研启动基金项目（BSQD12051）