Study On The Quality Chenistry Of Mengding Famous Tea

In recent years, the development and using of distinctive tea resources make the tea quality chemistry and brewing techniques highly concemed. Mengding famous tea is a kind of traditional and history tea which has sPecial Cultural connotation and drinking value. The PaPer aimed four representative Mengding famous tea such as Mengding Huangya, Shihu,Ganlu and Maofeng, systematically researched the quality chemistry of them. In the study, it referenced the theoretical knowledge and methods, such as Tea-Processing, Tea-biochemistry and Tea-cultivation. The main results of study are as follows:(1) This PaPer firstly tested the main quality ingredient contents in Mengding famous tea, exPlored the difference of Huangya and Shihua, Ganlu and Maofeng, and discussed the stability of tea from different manufacturer. The result showed, Mengding famous tea have abundant material, the water extract, free amino acid, TP, catechin, caffeine and soluble suger contents are higher, they respectively are 39.24% to 41.37%,4.64% to 5.66%,24.34% to 27.94%,14.73% to 16.76%,4.16% to 4.57% and 4.84% to 5.31%. The raw materials are tender, the ash content is 4.90% to 5.05%. Mengding Huangya has unique quality characteristics, the souP and leaf of it are yellow, the chloroPhyll and its comPonent contents are lowest. The chloroPhyll content of Huangya is 0.80mg/g.The flavor characteristics of four famous tea are different. The difference of TP content between Huangya and Shihua is obvious(F=12.9610*>F0.05(1,4)=7.71, P<0.05); The difference of water extract and free amino acid contents between Ganlu and Maofeng is obvious(F=8.3920* and 8.1920*>F0.05(1,6)=5.99, P<0.05); The difference of other ingredients contents are not obvious. The difference of quality ingredients in Mengding famous tea from different manufacturer is obvious, such as the difference of caffeine, catechin, TP and free amino acid contents are obvious or extremely obvious.(2) In the PaPer, tested the main ingredient contents in Mengding famous tea by detection means of acids automatic analyzer and high-HPLC etc. The result showed, the highest content of EGCG is 6.67% to 9.2%, second are ECG (2.5% to 3.39%) and EGC(2.56% to 3.98%). The contents of EGCG,EGC and catechin are lowest, this is the material reflect of sweet and mellow quality in Mengding Huangya. The theanine content in four kind of Mengding famous tea is above 2% and it is higher. The size order of main amino acids comPonents is theanine>glutamic acid>arginine>asPartate. The contents of K and Mg are abundant (above 1500mg/kg); the contents of Mn,Ca and Na are above 200mg/kg. The size order of ten kind of inorganic element comPonents is K>Mg>Ca> Mn>Na>Fe>Zn>Cu>Ni>Se.(3) This PaPer discussed the leaching characteristics of different comPonents in Mengding famous tea by three brewing methods, such as evaluation cuP, glass and bell cuP. The result showed, when brewing by evaluation cuP, the average leaching rate of water extract is 42.20% to 46.93%, the concentration of tea souP is 3.66mg/ml to 3.74mg/ml. The average leaching rate of amino acid and caffeine are higher, they are 55.24% to 76.16% and 58.23% to 66.08%; The average leaching rate of soluble sugar catechin and TP are lower, they are 31.99 to 39.76%,34.33% to 42.18% and 30.14% to 41.24%. Water quality obviously influence the leaching of free amino acid, caffeine and caffeine; extremely influence the leaching of soluble sugar. The influence of water extract and TP are not obvious by brewing of different water.As the brewing time is increasing, the leaching rate and concentration of water extract, free amino acid, soluble sugar and caffeine are gradually reducing by brewing of glass and bell cuP. When brewing of glass, the leaching rate and concentration of TP and catechin in the second tea souP are highest, then gradually reduce. Brewing after three times, the leaching rate and concentration of main tasted ingredients are 70 Percent of five times brewing; the ingredients have basically leaching; The tasted ingredient content in the fourth and fifth tea souP is little and no longer fit to drink.(4) AdoPtting comprehensive evaluation method to evaluate the organic evaluation results and Project, then further discussed the correlation of organic evaluation and leaching concentration of ingredient. The result showed, the scoring rate of Huangya is lowest and the quality difference is obvious; The figure and endoPlasm of some Huangya close to Shihua. The five Projects of organic evaluation are extremely obvious, the influence of savor and aroma to organic evaluation is strong, influence of leaf is weaker,the correlation of total score and water extract concentration in Huangya showed Y=-396.60+298.56x-45.71x2 ("Y" is total score, "x" is water extract concentration, R2=0.97502, P=0.0056); Shihua showed Y=-335.48+245.04x-34.99x2 (R2=0.81272, P=0.035). The correlation of savor score and TP concentration in Huangya showed Y=-275.23+376.09x-96.87x2(R2=0.9509, P=0.010). The correlation of savor score and caffeine concentration in Huangya showed Y=-1653.43+6655.03x-6347.70x2 (R2=0.92843, P=0.019); The correlation of savor score and caffeine concentration in Maofeng showed Y=62.08+48.43x("x" between 0.46mg/ml to 0.64 mg/ml, R2=0.8013, P=0.009).