Components analysis of Xuehua pear juice fermented by Lactobacillus caucasus LN6 and its potential mechanisms of ameliorating hyperglycemia by regulating gut microbiota

Hyperglycemia is a major public health concern. Probiotic-fermented fruit juices provide a feasible strategy to mitigate high blood glucose. This study aimed to screen a probiotic strain with hypoglycemic activity, investigate its biotransformation during the fermentation of Xuehua pear juice, and investigate the mechanisms underlying its effects against hyperglycemia in mice. Results indicated that <i>Lactobacillus caucasus</i> LN6 showed an excellent adaptability to fermentation condition, and the α-glucosidase inhibition rate of the fermented Xuehua pear juice (FPJ) increased from 38.73 % to 71.09 %. FPJ significantly decreased fasting blood glucose, insulin levels in type 2 diabetes mellitus (T2DM) mice. Importantly, FPJ modulated the gut microbiota by increasing the abundance of beneficial bacteria (<i>Lactobacillus</i>, <i>Dubosiella</i>, and <i>Bifidobacterium</i>) and reducing that of harmful bacteria (<i>Erysipelotrichaceae</i> and <i>Desulfovibrio</i>), thereby potentially contributing to an improved intestinal environment, enhancing insulin sensitivity, and lowering blood glucose levels. This study offers new perspectives for developing functional pear products.