本研究利用之前報導所分析的19項主要物化成分針對高山茶 (60件)、凍頂烏龍茶 (46件) 和鐵觀音 (34件) 之比賽茶共140件三大半球型烏龍茶類進行比較；並分別以逐步判別分析法和主成分分析法，結合線性鑑別分析法，探討此三茶類之鑑別。結果顯示，在19項分析的物化成分中，三種茶類有高達10項成分達顯著差異 (p < 0.05)，分別為catechin (C)、epigallocatechin gallate (EGCG)、總酯型兒茶素、總氮量、總游離胺基酸、茶湯測色值 (Hunter L、Hunter a和Hunter b)、茶湯彩度 (chroma) 和pH值等。鐵觀音具有較低pH值、總氮量、總游離胺基酸和高咖啡因、高酯型兒茶素之特徵；高山茶以含游離胺基酸及茶湯pH值較高為主要特徵；凍頂烏龍茶則介於兩者之間，但總游離兒茶素含量與高山茶相近，皆比鐵觀音高。以逐步判別分析法利用物化成分鑑別三大半球型烏龍茶，結果選出七項物化成分為最適鑑別成分，包括pH值、總游離胺基酸、epigallocatechin (EGC)、咖啡因、epicatechin gallate (ECG)、總兒茶素及總酯型兒茶素等，其鑑別成功率為91.43%。以主成分分析法結合線性鑑別分析法，利用前四個主成分，則可達100%鑑別成功率。台灣烏龍茶之發酵程度分析結果
則顯示，目前文獻記載各種烏龍茶之發酵程度仍有待釐清，高山茶之兒茶素含量不減反增，凍頂烏龍茶與鐵觀音之發酵程度與文獻所載亦有明顯差異。

The purpose of this study were to compare data of 19 physicochemical constituents, which were obtained in previously reported studies, of 140 semisphere-type Taiwan Oolong tea, belonging to 60 High mountain
tea, 46 Dong-ding Oolong tea and 34 Tiehkuanyin collected from famous tea contests, and to investigate the discrimination of them using the stepwise discriminant analysis and principal component analysis (PCA) with linear discriminant analysis (LDA). The results showed that ten out of 19 constituents were signifcantly different in these three types of tea samples (p < 0.05). They were catechin (C), epigallocatechin gallate (EGCG), total ester-type catechins, total nitrogen, Hunters L, a, and b values, chroma and pH. The characteristics of Tiehkuanyin tea samples were low in pH, total nitrogen and total free-type catechins but high in caffeine and ester-type catechins while that of High-mountain tea samples was rich in free-type catechins contents and high in pH of tea infusions. The Dong-ding Oolong tea samples were in between those two types of tea samples but the content of total free-type catechins were closer to that of High-mountain tea and both were higher than that of Tiehkuanyin. Using results of physicochemical analysis to conduct the stepwise discriminant analysis directly, the results showed that 7 items including pH, total free amino acids, EGC, caffeine, ECG, total catechins and total ester-type catechins, were the most suitable for discrimination. The percentage of successful discrimination was 91.43%. Using PCA with LDA, the frst four components could discriminate up to 100% successful rate. In terms of the fermentation level for the Taiwan Oolong tea, our results indicated that it requires clarifcation from the published data in the literature. This study showed that the catechins contents in High-mountain tea samples were increased instead of decreased, and the fermentation levels for the other two kinds of tea were also quite different from the data in the literature.