Study On The Pathway By Metabolomics Of Yellowing Substrate From Fresh-cut Chinese Water Chestnut (Eleocharis Tuberosa) And The Related Enzymes

Chinese water chestnut can improve digestion,removing heat-phlegm,it usually eat after peeling.The cutting surface will turn yellow in a short term,which affect the quality of its appearance.Different from most of fresh-cut fruits and vegetables,Chinese water chestnut presents etiolation during storage.Etiolation has negative effect on the commodity value and economic value.The fresh-cut water chestnut in different stage is taken as the experiment material,LC-MS is enabled to conduct metabolomic profiling.The different metabolites were assessed by using the PCA,PLS-DA,OPLS-DA methods.According to the differences of the metabolites,the network of metabolic pathway can be constructed.The feasibility of metabolic pathway is analyzed in the aspect of enzymology.Finally the research will illustrate the relationship between etiolation and enzymatic browning.The conclusion as follows:1.With the prolong of storage time,the b*value and C*value present rise first then fall.The content of naringenin and eriodictyol shows a trend of rise first then fall with the increasing storage time.The L#value declines with the increasing storage time.2.Metabonomics technology combines with multivariate statistical analysis is made to detect the major differences metabolites,including organic acids,flavonoids and suguars.The organic acids including,Salicylic acid,citric acid,ferulic acid,leucine,L-aspartate and lysine.The flavonoids including,Apigenin,Quercetin,Naringenin,Eriodictyol,Kaempferol,Myricetin.The saccharides including,Sucrose and glucose.3.Metabolic pathways of etiolation are established through the online database.Phenylalanine turns into Coumarate Coenzyme,then it into Naringenin Chalcone,and transform into Naringenin,Naringenin come into different pathways Firstly,it transform into Apigenin and its derivatives;Secondly,it can produce Eriodictyol and its derivatives.Thirdly it can produce Dihydrokaempferol,Quercetin and Myricetin.Of which the Eriodictyol can be further transformed to Luteolin,Cornflower,Dihydroquercetin,5 Hydroxy flavanone,etc.4.Through the analysis of the enzymes related to metabolic pathways,it indicates that there is a significant correlation between the activity of PAL,4CL,CHS,CHI,F3H,F3'H with the contend of naringenin and eriodictyol.It indicates that the naringenin and eriodictyol also need these enzymes in fresh-cut Chinese water chestnut,combined with the metabonomics result to determine the specific pathway of Chinese water chestnut yellowing:Phenylalanine turns into Coumarate Coenzyme under the action of PAL,C4H,4CL enzyme.CHS enzyme catalyzes it into Naringenin Chalcone,and turns into Naringenin by the function of CHI enzyme.Naringenin come into different pathways through different catalyzing enzymes,it can produce Eriodictyol and its derivatives by F3'H and produce Dihydrokaempferol and its derivatives with the action of F3H.5.PPO,POD,LOX are the enzymes connected with enzymatic browning,through the research of the enzyme activity,it shows that there have a significant negative correlation with PPO and LOX with etiolation b*value,but there is no relationship between POD and b*value.Thus,it can speculate that no correlation is observed between etiolation and PPO,POD,LOX.The conclusion that Chinese water-chestnut etiolation is different from enzymatic browning.