小麦提取物对乳酸杆菌胆盐耐受力的影响

Effect of Wheat Extracts on Bile Tolerance of Selected Strains of Lactobacilli

模拟人十二指肠高胆盐环境,研究小麦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小麦基质对乳酸杆菌的保护作用。将约氏乳酸杆菌JJB3、SNZ10,罗伊氏乳酸杆菌MNZ8、KNZ4株菌,在含有小麦提取物的10g/L胆盐溶液,pH7.0的磷酸盐缓冲液中作用4h,检测其活菌数。未添加小麦提取物的对照组4株乳酸杆菌活菌数显著下降(P<0.05),其中MNZ8对胆盐最为敏感,活菌数下降1.74lg(CFU/ml),KNZ4的耐受力最强,活菌数下降1.16lg(CFU/ml);添加小麦提取物后,4株乳酸杆菌的胆盐耐受力均显著提高(P<0.05),但对不同菌株提高程度有差异,其中,JJB3胆盐耐受力提高最明显,其活菌仅减少了0.11lg(CFU/ml)。葡萄糖和游离氨基氮(FAN)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。小麦提取物对4株乳酸杆菌耐受模拟十二指胆盐环境具有较好的保护作用,对约氏乳酸杆菌JJB3保护作用最好。

In order to explore the protection effect of wheat providing the matrix for production of probiotic foods on Lactobacilli, the effect of wheat extracts on viability of selected stains of Lactobacilli, including Lactobacillus johnsonii JJB3, SNZ10, and Lactobacillus reuteri MNZ8, KNZ4 was investigated under the circumstance of simulated bile juice. The viability of these strains was detected during exposure to 10 g/L bile for 4 h at pH 7.0. In additions, the effects of glucose and free amino nitrogen （FAN） on their bile tolerance with increasing concentration were also examined. In the absence of wheat extracts KNZ4 showed the greatest resistance to bile with a reduction of viable count of only 1.16lg （CFU/ml）, whilst MNZ8 displayed the greatest sensitivity with a reduction of viable count of up to 1.74lg （CFU/ml）. Addition of wheat extracts significantly improved the tolerance of all four strains （P 〈 0.05）, and JJB3 showed the highest bile tolerance and the viable population was decreased by 0.11lg（CFU/ml）. The extent of improvement was positively correlated with the concentration of soluble sugars and FAN present in the extracts. Glucose revealed a better effect than FAN. The results presented in this study indicate that wheat extracts exhibit a significant protective effect on the viability of four Lactobacilli strains under simulated bile conditions, especially for L johnsonii JJB3.