Guérin Daniel, Vuillemard Jean-Christophe, Subirade Muriel
Centre de Recherche en Sciences et Technologie du Lait STELA, Faculté des Sciences de l'Agriculture et de l'Alimentation, Université Laval, Québec, Canada G1K 7P4.
J Food Prot. 2003 Nov;66(11):2076-84. doi: 10.4315/0362-028x-66.11.2076.
Bifidobacterium cells were encapsulated in a mixed gel composed of alginate, pectin, and whey proteins. Two kinds of capsules were obtained: gel beads without membranes and gel beads with two membranes formed by the transacylation reaction. In vitro studies were carried out to determine the effects of simulated gastric pH and bile salts on the survival of free and encapsulated Bifidobacterium bifidum. The protective effects of gel beads without membranes and gel beads coated with two membranes formed by the transacylation reaction were evaluated. After 1 h in an acidic solution (pH 2.5), the free-cell counts decreased by 4.75 log units, compared with a <1-log decrease for entrapped cells. The free cells did not survive after 2 h of incubation at pH 2.5, while immobilized-cell counts decreased by about 2 log units. After incubation (1 or 3 h) in 2 and 4% bile salt solutions, the bifidobacterium mortality level for membrane-free gel beads (4 to 7 log units) was higher than that for free cells (2 to 3 log units). However, counts of bifidobacteria immobilized in membrane-coated gel beads decreased by <2 log units. Cell encapsulation in membrane-coated protein-polysaccharide gel beads could be used to increase the survival of healthy probiotic bacteria during their transit through the gastrointestinal tract.
双歧杆菌细胞被包裹在由海藻酸盐、果胶和乳清蛋白组成的混合凝胶中。获得了两种胶囊：无膜凝胶珠和通过转酰基反应形成两层膜的凝胶珠。进行了体外研究，以确定模拟胃pH值和胆汁盐对游离和包裹的两歧双歧杆菌存活的影响。评估了无膜凝胶珠和涂有通过转酰基反应形成的两层膜的凝胶珠的保护作用。在酸性溶液（pH 2.5）中孵育1小时后，游离细胞计数下降了4.75个对数单位，而包埋细胞的计数下降小于1个对数单位。在pH 2.5下孵育2小时后，游离细胞无法存活，而固定化细胞计数下降了约2个对数单位。在2%和4%胆汁盐溶液中孵育（1或3小时）后，无膜凝胶珠中双歧杆菌的死亡率水平（4至7个对数单位）高于游离细胞（2至3个对数单位）。然而，固定在有膜包裹凝胶珠中的双歧杆菌计数下降小于2个对数单位。将细胞包裹在有膜包裹的蛋白质-多糖凝胶珠中可用于提高健康益生菌在胃肠道转运过程中的存活率。
