Optimization Of Preparation Process Of Mulberry Leaf Instant Tea And Evaluation Of Lipid-lowering Effect On Mice

Mulberry leaves contain a variety of bioactive substances,with hypoglycemic,hypolipidemic,anti-inflammatory and other effects.At present,most of the studies on the functions of mulberry leaves are from the central and southern regions of China,while few studies on Mulberry Varieties in Northeast China.In this study,mulberry leaf instant tea powder was prepared by hot water extraction and freeze-drying method,and its lipid-lowering effect was evaluated by animal experiments.Firstly,response surface methodology(RSM)was used to optimize the preparation conditions of mulberry leaf instant tea.The solubility of mulberry leaf instant tea was determined,and its components were identified by liquid chromatography-mass spectrometry(LC-MS).The results showed that the optimum preparation conditions of mulberry leaf tea were as follows:temperature:95?,solid-liquid ratio:1:15,particle size:250?m,and the yield of mulberry leaf instant tea was 25.35±0.52%.The results of solubility test showed that the solubility of mulberry leaf instant tea was 78%,the dissolution time was 114.02 s,and the fluidity was 8 cm.173 compounds were identified by LC-MS,among which the detected nutrients were valine,threonine,cysteine,leucine,isoleucine and proline.Vitamins:vitamin B₂,vitamin B₆,ergocalcidol(d vitamins),pantothenic acid,nicotinic acid.Sugars:mannose,galactose,etc.The active components are flavonoids:Quercetin,isoquercetin,taxol,scopoletin,scutellarin,dihydroxyflavone.Phenols:chlorogenic acid,cyanidin-3-o-glucoside,trans resveratrol glycoside.Sugars:d-aloulose.Amino acids:?-aminobutyric acid.It can be seen from the above components that mulberry leaf instant tea is rich in nutrients.In animal experiment,remission group and prevention group were set up.The remission group was intervened with different doses of mulberry leaf instant tea after modeling with high-fat diet,which was divided into normal control group(A),negative control group(B),low-dose group(C)and medium dose group(D);the prevention group was intervened with different doses of mulberry leaf instant tea while modeling with high-fat diet,which was divided into normal control group(E)and negative control group(F),high,medium and low dose groups(G,H,I).After the intervention,the Lee's index,fat coefficient and serum biochemical indexes of remission group C and D were significantly lower than those of group B(p<0.05).Compared with group F,the Lee's index,fat coefficient and serum biochemical indexes of group G,H and I were significantly decreased(p<0.05).It can be seen from the results of intestinal flora that mulberry leaf instant tea has adjusted the structure of intestinal flora of mice at the phylum and genus levels,and the relative abundance of Desulfovibrio(Desulfovibrio)has decreased in the relief group C and D.The relative abundance of G,H and I Akkermansia,Bifidobacterium and Lactobacillus in the prevention group increased.The abundance of Deferribacteres and Desulfobacterota has been reduced.The beneficial bacteria were increased and the harmful bacteria were decreased.This experiment optimized the preparation process of mulberry leaf instant tea,and proved that it has certain lipid-lowering and intestinal flora regulating effects on mice,which provides data support for the subsequent study of mulberry leaf lipid metabolism regulation in cold region.