Study On The Characteristics Of Mulberry Leaf Fu Tea And Evaluation Of Its Hypoglycemic Effect

Mulberry leaf（Morusalba L.）,as a medicinal and edible plant,has been used in the clinical treatment of diabetes for a long time,and its curative effect is definite.Modern pharmacological studies have shown that mulberry leaf contains polyphenols,polysaccharides,alkaloids and other active substances,all of which have Auxiliary hypoglycemic effect.As a potential probiotic,Eurotium cristatum has broad application prospects in improving the quality of tea.In this study,the mulberry leaf raw dark green tea obtained from the pure mulberry leaves through the primary production process of raw dark green tea was used as the substrate,artificially inoculated with Eurotium cristatum for solid-state fermentation,and the loose mulberry leaf Fu tea was prepared.The mulberry leaf variety with the most fermentation adaptability was determined through comparative analysis,and the fermentation process was optimized.On this basis,the brewing characteristics and storage characteristics of mulberry leaf tea were explored.In addition,the hypoglycemic activity of mulberry leaf Fu tea was explored from two aspects in vitro and in vivo.To provide a reference for the utilization of mulberry leaf resources and the development of auxiliary hypoglycemic functional tea products,the main research contents and conclusions are as follows:（1）Shaansang 707,Yuesang 10 and Husang 32 three kinds of mulberry leaf raw dark green tea were made into mulberry leaf Fu tea through solid fermentation by Eurotium cristatum respectively.The nutritional and active components,sensory quality and inhibition rate ofα-glucosidase were determined.,selected"Yuesang No.10"as the most suitable mulberry leaf variety for fermentation.According to the determination,"Yuesang No.10"was selected as the most suitable mulberry leaf variety for the fermentation of Eurotium cristatum;The process was optimized,and the best process conditions were determined as follows:moisture content 30%,pile for 8 hours,inoculation amount 25%,flowering for 7days,the mulberry leaf Fu tea prepared under these conditions has similar characteristics with the traditional loose Fu tea.（2）Taking Yuesang No.10 mulberry leaf Fu tea as the research object,the influence of Eurotium cristatum fermentation on mulberry leaf tea was further explored.Fermentation reduced the IC₅₀ of mulberry leaf tea toα-glucosidase from 0.84mg/m L to 0.29mg/m L,that is,it significantly increased the hypoglycemic activity of mulberry leaf tea,and the inhibition of mulberry leaf Fu tea onα-glucosidase was reversible and non-competitive.In addition,the main active components and chromaticity of mulberry leaf Fu tea at different storage temperatures were dynamically monitored and analyzed,and it was found that mulberry leaf Fu tea is more suitable for storage at room temperature.（3）Using a variety of nutritional active ingredients andα-glucosidase inhibition rate as indicators,the brewing characteristics of mulberry leaf Fu tea under the two methods of boiling and steeping were explored.After comprehensive analysis,it was determined that the tea-water ratio was 1:80 and boiled for 8 minutes or the tea-water ratio was 1:50 bubbles for15 minutes and within three bubbles are the best brewing conditions.In addition,the results of GC-MS showed that the mulberry leaf Fu tea had both the unique aroma of mulberry leaves and the sweetness and mellowness of fermentation.Moreover,the brewing method has a great influence on the volatile components of mulberry leaf tea,and mulberry leaf Fu tea is more suitable for brewing.（4）In order to verify the hypoglycemic effect of mulberry leaf tea in vivo,a high-fat diet combined with streptozotocin was used to construct type 2 diabetes model mice.After the intervention treatment of mulberry leaf tea,the FBG of diabetic mice decreased from19.05mmol/L to 15.25mmol/L,the HOMA-IR decreased from 8.96 to 7.42,and the lesions of liver,pancreas,kidney and adipose tissue were also effectively improved;in addition,mulberry leaf Fu tea can also promote the production of short-chain fatty acids in the intestines of mice.The diversity of intestinal flora in mice was analyzed,and it was found that mulberry leaf Fu tea can increase the abundance of beneficial microorganisms such as Faecalibaculum,Lactobacillus and Bifidobacterium,and reduce the abundance of pathogenic bacteria such as Aerococcus and Enterococcus,so as to reshape the intestinal flora.