Taste Quality Constitute Of White Tea Based On Modern Quality Instrumental Assessment

White tea,as the unique tea category to Fujian,is one of six Chinese tea.The flavor ingredient in White tea is complex.If the type,content and proportion of ingredient is different or changed,so is the taste of White tea.In this research,the sample of White Peony and Siver Needle Pekoe which was from different region and grades was applied as the main material,the main flavor substances of white tea is detected by modern quality instrumental assessment(including electronic tongue,high performance liquid chromatography,automatic amino acid analyzer,inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry,etc.),and the sensory evaluation refered to description quantitative analysis of food sensory evaluation techniques,and combined with correlation analysis,principal component analysis,discriminant analysis,decision tree analysis,stepwise linear regression method and other stoichiometries,which aim to evaluate the quality of White tea,including discrimination of tea grade and producing region,and to explore the method and the application of modern quality instrumental assessment on testing White tea quality.The main results and conclusions were listed as followed:(1)It was found that there were differences among the samples with different grades,region by the chemical analysis.And the results of sensory evaluation were listed as followed:the fresh was disappear as decline as the grade,the taste of Silver Needle Pekoe was characterized by fresh brisk and sweet,as the white peony was characterized by mellow;as the samples of Fuding was by fresh and concentrated;as Zhenghe was mainly mellow.With Fisher discriminant analysis establish discriminant model for discriminant analysis.The overall correct identification rate of Siver Needle Pekoe samples was 100%,so is the each grade.The overall correct identification rate of White Peony samples was 86.8%,the each grade was 92.3%,60.0%and 100%,respectively.The overall correct identification rate of different producing region samples was 100%.The results showed that the effect of discrimination of chemical composition was better for different grades and regions sample.(2)The correlation analysis was applied between taste sub attributes(fresh,sweetness,bitterness,astringency)and taste the chemical composition of different grades and producing region samples.The results were as follow.The fresh was significantly positive with free amino acid,cystine,glutamic and glycine,contrary with caffeine,thearubigins,theabrownin,catechin,total catechin,proline,methionine.The sweetness was significantly positive with free amino acid,glutamic and glycine,contrary with caffeine,flavonoids,theaflavin,thearubigins,theabrownin,gallic acid,chlorogenic acid,myricetin,quercetin,arginine,leucine,lysine,proline,alanine acid,phenylalanine,cystine.The bitterness was significantly positive with Caffeine,flavonoids,theaflavin,thearubigins,theabrownin,myricetin,kaempferol,valine,cystine,isoleucine.The astringency was significantly positive with Caffeine,thearubigins,theabrownin,kaempferol,valine,cystine,isoleucine,contrary with free amino acids,theanine,glutamic,serine,valine.(3)Using Fisher discriminant analysis and decision tree establish the classification models for different grades and producing region samples.The models showed that the correct identification rate of Siver Needle Pekoe samples was 90.5%,each grade of the samples(1,2,3)were 100%,74.1%and 100%,respectively.The White Peony samples was 86.8%,each grade of the samples(1,2,3)were 92.3%,20.0%and 86.7%,respectively.The overall correct identification rate of different producing region samples was 100%.The stepwise linear regression model were established between the chemical composition,sensory evaluation and electronic tongue with different grades and producing region,and the models were statistically significant and better goodness of fit.Also,the responsed degree of each sensor was different in different models,the sensor palladium electrodes was an important sensor of taste of different grades Silver Needle Pekoe,as the sensor silver electrode,a platinum electrode,a titanium sensor electrode were of white peony,the sensor titanium electrode,silver electrode are important sensors of different origin show white tea tea taste characteristics,frequency 100Hz silver electrodes in three taste the chemical composition,sensory evaluation of the linear regression model has played an important role in its tea taste bitter and umami substances response was obvious.