Effects Of Lactic Acid Bacteria Fermentation On Nutrient Composition And Hypoglycemic Activity Of Chickpea Milk

Diabetes is a chronic metabolic disease that can cause various complications such as diabetic ketoacidosis,hypertension,nephropathy,and dyslipidemia.Long-term hypoglycemic drugs are needed to control blood sugar,and these drugs usually have side effects such as weight gain,increased risk of hypoglycemia,body fluid retention,and heart failure.Therefore,there is an urgent need to find new safe and effective intervention methods to reduce blood sugar without side effects.Chickpea is a medicinal and food plant resource with high nutritional value and various physiological functions such as hypoglycemia and antioxidant,which is a high-quality raw material for developing functional food and suitable for diabetic diet.Some lactic acid bacteria have the effect of lowering blood sugar and improving the flavor and quality of food through fermentation,which have been widely used in the food industry.This project is a strong combination of these two food ingredients with hypoglycaemic activity,firstly screening lactic acid bacteria with excellent probiotic properties,and improving the nutritional value and hypoglycaemic activity of chickpea milk with lactic acid bacteria fermentation,providing a theoretical basis for the development of functional plant-based fermented soymilk with hypoglycaemic effect.In this thesis,the probiotic properties and hypoglycaemic activity of L.kefir BNCC190565,L.acidophilus ATCC 4356,L.buchneri BNCC 187964,L.casei CICC 23184 and L.plantarum subsp.plantarum CICC 20279 were studied in comparison,using the good commercial strain Lactobacillus rhamnosus GG as a positive control.The results showed that L.acidophilus ATCC 4356 and L.plantarum subsp.plantarum CICC 20279 not only had good antioxidant,cholesterol and blood glucose lowering abilities,but also good gastrointestinal tolerance,and were selected as strains for fermenting chickpea milk.Both L.acidophilus ATCC 4356 and L.plantarum subsp.plantarum CICC 20279 can proliferate normally in chickpea milk.At 20 h of single and mixed fermentation,the content of soluble sugars and protein in chickpea milk decreased,but the content of dietary fibre,free amino acids,flavonoids,polyphenols and other active ingredients increased significantly.Both single and mixed fermentations increased the α-glucosidase inhibition of chickpea milk.L.acidophilus ATCC 4356 fermented chickpea milk showed the best α-glucosidase inhibition,ranging from 84% to 93%.The conjugated,bound and free polyphenols of L.acidophilus ATCC 4356 fermented chickpea milk were extracted.It was found that the fermentation significantly increased the content of conjugated and free polyphenols in chickpea milk,and the inhibitory effect of conjugated polyphenols on α-glucosidase and α-amylase was significantly higher than that of bound and free polyphenols.The chickpea milk fermented by L.acidophilus ATCC 4356 for 20 h had the best comprehensive performance.Lastly,the effects of L.acidophilus ATCC 4356 fermented chickpea milk on diabetic symptoms and intestinal flora in mice were investigated by establishing a type II diabetic mouse model.The results show that:(1)Fermented chickpea milk could alleviate the symptoms of elevated blood glucose and reduced body weight in diabetic mice.Fermented chickpea milk could improve the liver and kidney damage in diabetic mice.(2)Fermented chickpea milk reduced the abundance of Proteobacteria pathogenic bacteria in the intestinal flora of diabetic mice and increased the abundance of Anaerolineae,Akkermansia,Bacteroides,Faecalibaculum and Akkermansia muciniphila,which may be one of the reasons why fermented chickpea milk improved the symptoms of diabetes in mice.In addition,fermented chickpea milk was superior to unfermented chickpea milk in regulating the ratio of Firmicutes to Bacteroidota in the intestinal flora of diabetic mice,reducing the pathogenic bacteria of Proteobacteria and increasing the abundance of the second generation probiotic Akkermansia muciniphila.In conclusion,L.acidophilus ATCC 4356 and L.plantarum subsp.plantarum CICC20279 have excellent probiotic properties and hypoglycaemic activity,and the nutritional value and hypoglycaemic activity of chickpea milk can be enhanced by fermentation.L.acidophilus ATCC 4356 fermented chickpea milk improved diabetic symptoms and increased the abundance of beneficial bacteria in the gut of diabetic mice.