台灣高山茶之化學特性與等級之鑑別

Chemical Characteristics and Discrimination of Different Grades of Taiwan High-mountain Tea

劉士綸(Shih-Lun Liu) ； 蔡永生(Yung-Sheng Tasi) ； 區少梅(Shau-Mei Ou)

《臺灣農業化學與食品科學》 46卷2期 (2008/04) Pp. 70-77

https://doi.org/10.6578/TJACFS.2008.009

摘要

本研究自台灣高山茶主要產區的嘉義地區之比賽茶中，選取三個不同產季，不同等級之高山茶為試驗材料，共計60個樣本。就其主要化學成分含量進行分析，以建立台灣高山茶之化學成分基本資料，並找出屬於台灣高山茶之特色成分。另探討三個不同等級之高山茶比賽茶間化學成分之差異，同時結合主成分分析與線性鑑別分析，嘗試找出影響台灣高山茶品質及等級之重要成分。結果顯示，茶湯pH值及游離胺基酸與總游離型兒茶案含量均較高為台灣高山茶之主要特色。高山茶茶湯之pH值為5.61，高於凍頂烏龍茶(5.40)與鐵觀音茶(5.11)；其游離胺基酸平均含量為1.92%，亦高於後兩者（1.41%與0.50%）；而總游離型兒茶素平均含量為7.38%，則與凍頂烏龍茶(7.73%)相近但高於鐵觀音茶(6.22%)。在不同等級高山茶之化學成分方面，三個等級之高山茶在大多數化學成分間均具顯著差異，但在等級間化學成分含量多寡並無一致趨勢。主成分分析之結果，前三個主成分可解釋茶樣間78.54%之變異，惟亦無法有效區分不同等級高山茶。另以主要化學成分進行各等級比賽茶之鑑別分析，所得之判別成功率僅65%。本研究顯示由評鑑委員所判定的不同等級高山茶，尚無法利用其主要化學成分的鑑別分析結果判別之。

關鍵字

台灣山茶 ； 主要化學成分 ； 線性鑑別分析 ； 主成分分析

並列摘要

Total 60 High-mountain tea (HM) samples of three different grades evaluated in High-mountain tea competitions in ChiaYi County from different production seasons were selected as materials. Their major chemical constituents were analyzed and compared, in order to establish the basic constituent profile and to find out the characteristics of HM produced in Taiwan. In addition, the difference in the chemical constituents among these lea samples of different grades was investigated and discriminated by using principal component analysis (PCA) and linear discriminant analysis (LDA). The results showed that the relatively higher pH value and higher contents of free amino acids and free-type catichins were the characteristics of HM as compared to Dongding-Oolong tea (DDO) and Tiehkuanyin tea (TKY). The pH (5.61) of HM was higher than that of DDO (5.40) and TKY (5.11). The average content of free amino acids in HM was 1.92% and also higher than in DDO (1.37%) and TKY (0.50%). The average content of total free-type catechins in HM was 7.38%, which was close to DDO (7.73%) but higher than TKY (6.22%). Most of the chemical constituents among three grade samples varied significantly, but there were no analogous tendencies among them. The results of PCA showed the explanation ability for sample variation reached to 78.54% with the first three principal components, but stilt the three grades of High-Mountain tea were not welt separated. The results of LDA with major chemical constituents showed the discriminating ability for the different grades of High-mountain tea only 65%. It indicated that the different grades of High-mountain tea evaluated by judges could not be discriminated by these major chemical components examined in this study.

並列關鍵字

Taiwan High-mountain tea ； Major chemical constituents ； Linear discriminant analysis ； Principal component analysis