麦芽提取物对乳酸杆菌胆盐耐受力的影响

Influence of Malt Extracts on the Bile Tolerance of Selected Strains of Lactobacilli

模拟人十二指肠高胆汁盐环境,研究麦芽提取物对乳酸杆菌胆盐耐受力的影响,探讨作为生产益生菌食品的麦芽基质对乳酸杆菌的保护作用。将选定的约氏乳酸杆菌JJB3、SNZ10,罗伊氏乳酸杆菌MNZ8、KNZ4等4株菌在含有1%胆盐溶液,pH为7.0的磷酸盐缓冲液中作用4h,检测活菌数。结果表明:在未添加麦芽提取物的对照组,4株乳酸杆菌菌数极显著下降(P<0.01),其中MNZ8对胆盐最为敏感,活菌数下降1.74log10cfu/mL,而KNZ4的耐受力最强,仅下降1.16log10cfu/mL;在添加了麦芽提取物后,4株乳酸杆菌的胆盐耐受力均有显著提高(P<0.05),其中SNZ10、JJB3两株菌胆盐耐受力提高最为明显,其菌数与对照组相比分别提高了1.21、0.79个对数单位。进一步分析表明,葡萄糖和游离氨基氮的浓度与乳酸杆菌耐胆盐能力的提高呈正相关关系,但葡萄糖的保护作用显著高于游离氨基氮的效果。该结果显示,麦芽提取物对4株乳酸杆菌在模拟十二指胆盐环境中具有较好的保护作用,以SNZ10、JJB3较果最好。

The bile tolerance of four strains of lactobacilli, selected malt substrates and tolerate simulated gastric transit was examined. on the basis of their ability to ferment Lactobacillus johnsonii JJB3, SNZ10, and Lactobacillus reuteri MNZ8.KNZ4 were exposed to 1% bile for 4 h in a phosphate--saline buffer at pH 7.0. The effects of supplementing the assays with wheat extracts, increasing concentrations of glucose, and free amino nitrogen were also examined. In the absence of wheat extracts KNZ4 showed the greatest resistance to bile, whilst MNZ8 displayed the greatest sensitivity. Addition of wheat extracts improved the tolerance of all four strains, and SNZ10, JJB3 showed the highest bile tolerance improving viability by 1. 21 log10cfu/mL. The extent of improvement was related to the concentration of soluble sugars and FAN present in the cereals, this was illustrated further by the addition of glucose to the assays, as the viability of the organisms was progressively improved with increasing concentrations. The presence of free amino nitrogen also increased bacterial resistance to bile but to a lesser extent both glucose and cereal extracts. The results presented in this study indicate that Malt extracts exhibit a significant protective effect on the viability of 4 strains of L. johnsonii and L. reuteri under bile conditions, which would be used as good delivery vehicles for probiotic SNZ10 .JJB3.