Abstract:

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 1.16 lg (CFU/ml), whilst MNZ8 displayed the greatest sensitivity with a reduction of viable count of up to 1.74 lg (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 0.11 lg(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.

Key words: wheat, extracts, Lactobacilli, bile tolerance