茶叶Journal of Tea 2013，39(4)：491492 Yuexiang Longjing Tea and Its Quality Characteristics Qian XD，Wang XG，Zhong FY Forestry Bureau of Shengzhou City，Shengzhou，Zhejiang Province，China Abstract Shengzhou is a major tea producing county in China and the major tea produced in Shengzhou is Yuexiang Longjing tea Environment and tea cuhivar are two important factors influencing tea quality Chemical composition of tea samp1es prepared using materials from cultivarsZhenong-1 17 andBaiye一1were investigated It showed that concentrati0ns of tcltal amino acids and catechins were more than 44and 129 mgg respectively，suggesting that Yuexiang Longjing had a good quality potential Key words Camellia sinensis；quality；chemical composition；amino acids；cateehins Shengzh0u city is the”township of Chinese tea”，in which there is tea garden area of 180000 mu or 12000 ha， with an annua1 tea vield 0f 22000 tons in which more than 6000 tons are Yuexiang Longjing teaThe Yuexiang Longjing tea is the major tea products produced in Shengzhou and it has been sold all over the countryShangdong Province is the major consumption area of Yuexiang Longjing tea，with annual sales of more than 2500 tons The good quality of Yuexiang Longjing tea is considered to be related to its nice environments and improved tea cultivars Shengzhou surrounded by beautiful mountains， with Jiuqudanxi River traversing it， has a mild and humid climateabundant rainfall，in which tea plants are suitably grownThe tea gardens of Zhengzhou City are located at an altitude of 300 meters to 500 meters of hills and mountains，with fertile soil and perennial misty Zhenong-1 1 7andBaiye-1are two major tea cultivars grown in Shengzhou tea areaThe chemical compositions of Yuexiang Longjing tea prepared using these two cuhivars were determined in the present paperThe information will be helpful for tea farmers in selecting a suitable tea cuhivar for their new tea fields 1Materials and mathods Tea samples of Yuexiang Longjing tea were collected from tea farmer s farm whereZhenong一1 17and Baiye-1 were grownDetermination of chemical composition was carried out according to the published references 2Tea polyphenol(TP)and amino acids(AA)were determined by spectrophotometrie methods，i eferrum tartrate dying method f0r TP and ninhydrin dying method f0r AA Data analysis was carried out using analysis of varance student s t-test on SPSS 100 for Windows(SPSS， Inc，Chicago，IL，USA) 2Results and discussions 21Concentration of amino acids Amino acids concentrati0n in the samples of Yuexiang Longjing tea prepared using cuhivarsZhenong一1 1 7 andBaiye1was 4447and 4769，respectivelyCaffeine concentration in the two tea sample w 3381and 3442，respectively(Table 1) 22Concentration of tea catechins Epigall0catechin gaIlate (EGCG)was the most abundant catechins in the tea samples，which was more than 500f total catechins(Table 2)Epicatechin gallate(ECG)was the next abundant catechins，and catechin gallate was the leastEpimers of catechins were found in fresh tea leaf and their isomers were formed owing to the 492 茶叶Journal ofTea 39卷 transformation of epimers of catechins under heating conditionThere were low levels of gallocatechin(GC)， catechin(C)，gallocatechin gallate(GCG)and catechin gallate(CG)in the samples，suggesting that the isomerization of epimers of catechins was not severe during Yuexiang Longjing tea processingBased on the total catechinscuhivarZhenong一1 17had higher catechins level thanBaiye-1 Table 1Concentration of amino acids(，DW) Table 2Concentration of tea catechins(mgg) Amino acids such as theanine are considered major astringent taste compounds，while caffeine to be major umami taste components in tea，and catechins are has bitter tasteCuhivarBaiye-1had higher amino acids concentration than cultivarZhenong一1 17This is consistent with the sensory assessment results that Yuexiang Longjing tea prepared usingBaiye一1had stronger umami taste thanZhenong-1 17while sample prepared usingZhenong一1 17had a stronger astringent tasteIt was revealed that the perceived taste score was positively correlated with the concentration of total amino acid and theanine，and total quality score was positively correlated with total amino acid The concentrations of catechins and amino acids were much higher than the Longjing tea samples collected from West Lake districts ，suggesting that Yuexiang Longjing had a good quality potentia1 References 1Zhong LPhysicochemical quality analysis of teaShanghai Science and Technology Press：Shanghai，China1989，258-338 2Lin DH，Zhu LZ，He W，Tu YYTea plant uptake and translocation of polycyclic aromatic hydrocarbons from water and around airJournal of Agncultural and Food Chemist，2006，54：3658-3662 3Wang KB，Ruan JYAnalysis of chemical components in green tea in relation with perceived quality，a case study with Longjing teasInternational Journal of Food Science and Technology