Study The Effects Of Anti-oxidation And Losing Weight Of Yunnan Black Tea

Objectives:To study the anti-oxidation ability and the mechanism of losing weight of the water extract of Yunnan Black Tea.Discuss the effects on aroma components and functional components of baking Yunnan black tea,so as to provide scientific basis of improving quality and health function of Yunnan black tea.Methods:1.The antioxidant capacity of the concentrations of 0.01g/mL and 0.02g/mL,0.03g/mL,0.04g/mL,0.05g/mL water extract was determined by 1,1-dipheny-2-picrylhydrazyl radical scavenging and total reducing power assays in vitro.C.elegans were fed with NGM culture medium contain the water extract concentrations of 0.05g/mL and 0.1 g/mL determined the activity of antioxidant enzymes.In addition,,C.elegans were exposed to H2O2 and paraquat medium to observe the lifespan,as to evaluate the antioxidant capacity and antioxidant stress level of YNBT in vivo.2.The obesity C.elegans model was fed with high-cholesterol and the water extract of YNBT with concentrations of 0.05g/mL and 0.1g/mL were used as control and high concentration cholesterol was used to co-culture the C.elegans.Then the intestinal lipid droplets were observed under fluorescence microscopy by Nile Red staining,and triglyceride content in nematode was determined by enzyme labeling apparatus.The RNA of C.elegans was extracted and the gene expression levels of sbp-1,fat-5,nhr-49,nhr-80,daf-22 and daf-2 were determined by real-time fluorescence quantitative PCR.Aim to observe the changes of intestinal lipid droplets,triglycerides and gene expression of nematodes cultured in different ways.3.The Yunnan Black Tea 100g were put on drying box,at 70?,90?,110?and 130? backing for lh,2.5h,and 4h,by Simultaneous Distillation and Extraction(SDE)and Gas Chromatography Mass Spectrometry(GC-MS)determined and analyzed the aroma composition,by high performance liquid chromatography(HPLC)determined the contents of gallic acid(GA)and catechins.Results:1.The total reducing power of the water extract of YNBT became stronger as the increasing concentrations.When the concentration of the water extract of YNBT reached 0.04g/mL,the reductive activities was the strongest and the concentration of 0.05g/mL showed a decreasing trend.The clearance rate of DPPH increased with the concentration increase,the clearance rate was the strongest at 0.05g/mL,but a little decreased at 0.04g/mL,and then increased rapidly.Determination the SOD and CAT activities in C.elegans,compared with the control group,adding water extract from YNBT could significantly increase the level of antioxidant enzymes(P<0.05),and the activity of SOD and CAT increased 1.18 and 1.14 times respectively at the concentration 0.05g/mL,and the SOD and CAT activities were improving 1.14 and 1.47 times at the concentration 0.1g/mL.C.elegans were exposed to 30%hydrogen peroxide medium,the survival time at 5.7d,9.53d and 11.13d of control group,the 0.05g/mL and 0.1g/mL extract of YNBT groups.Compared with the control group,the average survival time of C.elegans in the extracts with 0.05g/mL and 0.1 g/m was obviously prolonged(P<0.05)by 67.19%and 95.26%.The average survival time of C.elegans exposed to 200 mm paraquat was 7d,10.36d and 9.86d,compared with the control group,the average survival time of C.elegans in the water tea extract group of 0.05g/mL and 0.1g/m was significantly prolonged 48%and 40.86%(P<0.05).2.High concentration of 5mM cholesterol could improve obesity model of C.elegans.Compared with the control group,obesity group and the different concentration water extract group of YNTB,found that the lipid droplet density and volume and triglyceride content was significantly higher than the control group and the tea water groups(P<0.05).The relative expression of fat-5,nhr-49,nhr-80,sbp-1 and daf-22 gene in obesity group was higher than that control group(P<0.05),there was no difference in the expression of daf-2 gene(P>0.05).When the comparing the water extract of YNBT and obesity group found the expression of fat-5,nhr-49,nhr-80,sbp-1,daf-22 was lower than the obesity C.elegans(P<0.05).3.After baking,65 aroma compounds were detected in Yunnan Black Tea,including of alcohols,aldehydes,ketones,lactones,acids and heterocyclic compounds.The aroma substances with higher contents were 3-methyl butyraldehyde,2-methyl butyraldehyde,phenylacetaldehyde,and bran alcohol,benzyl alcohol,?-methyl-?-[4-methyl-3-pentenyl]ethylene oxide methanol,cis-?,linalool,phenethyl alcohol,geraniol,orange tertiary alcohol,phytol,methyl salicylate,ethyl palmitate?-5-trimethyl-5-vinyl-tetrahydrofuran-2-methanol,2,2,6-trimethyl-6-vinyl-tetrahydro-2H-furan-3-olB,2,2,2,6-trimethyl-6-vinyltetrahydro-2H-furan-3-olA,Linoleic acid methyl ester,linolenic acid methyl ester,linoleic acid ethyl ester,etc.In the baking process,benzyl alcohol,phenylethyl alcohol and geraniol with rose and flower aroma,linalool and linalool oxide with chestnut and wood aroma,?-ionone and orange tertiary alcohol with sweet aroma,the contents of a-terpinol with rosin and methyl salicylate with milk flavor increased significantly at 70? and 90? for 1-4 h.The volatile components of pyrazine,pyridine and indole with roasted and scorched aroma increased gradually with the increase of baking temperature,the content of indole and pyridine reached the highest at 110? for 4h,and pyrazine was baked at 130?.The content of tea polyphenols(TP)decreased with the prolongation of baking temperature and time.The content of Gallic acid(GA)increased rapidly with the prolongation of baking time,at 70?,90?,110? and 130?.For catechins,the content of catechin(C)increased with the increase of baking time and temperature,and the content of catechin reached its peak at 130? for 2.5 h.The content of Epigallocatechin(EGCG),epigallocatechin(EGC),epigallocatechin(ECG),epigallocatechin(EC)increased at 70? and 90? for 1-2.5 h.When the temperature rises above 110?,the content of baking decreased rapidly when the baking temperature reached 130?.Conclusions:1.We found strong antioxidant ability in vitro and in vivo of the water extract of YNBT,which was enhancement of DPPH radical scavenging and improvement the reduction power.In addition,it could increase the activity of SOD and CAT,and reduce the oxidative stress danage and prolong the survival time of C.elegans in oxidative stress environment.With the higher concentration of water extract from YNBT,the enzyme activity was higher and the survival time was longer of C.elegans.2.Cholesterol was a good substance to induce C.elegans obesity.However,the water extract of YNBT had the function of reducing weight and lipid-lowering of C.elegans.The obesity C.elegans fed in nematode growth mediator(NGM)content water extract of YNBT,the lipid volume and density and the triglyceride,and the genes expression of sbp-1,fat-5,nhr-49,nhr-80 and daf?22 were decreased.It could be concluded that the water extract of YNBT played a role in reducing weight and lipid-lowering by blocking the production of monounsaturated fat,reducing the synthesis of triglycerides.Increasing the activity of phosphate oxidase,improving the occurrence of ?-oxidation reaction,promoting the oxidative decomposition of fatty acids,and reducing fat storage.3.With different baking temperature and time of YNBT,we found that benzyl alcohol,Phenethyl alcohol,geraniol,linalool and its oxides,?-ionone,orange tertiary alcohol,methyl salicylate and ?-terpinol and other major aroma components were increased after baking at 70? and 90? for 1-2.5h.Backing could promote the occurrence of Maillard reaction,pyrrole,furan,pyrazine volatile substances increased,enhance the aroma of tea.At the same time,the non-enzymatic oxidation of tea polyphenols could be transformed into Gallic acid(GA)and catechins under heating conditions,and the health function of Yunnan black tea could be improved.In addition,baking can effectively reduce the moisture content of YNBT and prolong the storage time.