義式咖啡機沖泡茶葉法對茶湯品質及感官特性之影響

The Effects of Espresso Extraction on the Properties and Sensory Qualities of Oolong Tea

簡思平(Se-Ping Chien) ； 林慈婷(Cih-Ting Lin)

《臺灣農業化學與食品科學》 52卷1期 (2014/02) Pp. 8-14

https://doi.org/10.6578/TJACFS.2014.002

摘要

本研究選用臺灣南投產區的金萱（台茶12號）為茶樣，製成部份發酵茶（烏龍茶），探討不同研磨程度之茶葉（粗研磨組為＞30mesh；細研磨組為＜30mesh），在義式咖啡機沖泡法（器沖法）及熱泡法萃取下，對茶湯色澤、pH值、咖啡因、總兒茶素、總游離胺基酸及感官特性之影響。結果發現，不同研磨程度之器沖烏龍茶湯，其L、a、b值與熱泡無顯著差異（p＞0.05）；pH值則顯著高於熱泡茶湯（p＜0.05）；咖啡因含量皆顯著低於熱泡法（p＜0.05）；而總兒茶素、總游離胺基酸含量則以器沖法顯著高於熱泡法（p＜0.05），且茶葉粒徑愈小，茶湯中的總游離胺基酸含量愈高（p＜0.05）。不同萃取條件茶湯之定量描述分析結果，在外觀描述項目中，器沖茶湯之澄清度顯著優於熱泡組（p＜0.05），而在黃綠色澤上，以細研磨之器沖茶湯明顯最深（p＜0.05）；在香氣的描述項目中，器沖細研磨組以焙火香及清香表現較其他二組明顯（p＜0.05），但器沖粗研磨組之茶湯在焙火香及青草香表現卻顯著弱於其他二組（p＜0.05）；在滋味的描述項目中，器沖細研磨組茶湯在澀味及苦味的感受強度也比其他二組高（p＜0.05）；而在餘後感的描述項目中，不論研磨粗細，回甘、回香、生津在器沖茶湯的感受皆明顯強於熱泡茶湯（p＜0.05）。總之，器沖粗研磨是感官整體表現較理想的萃取條件。

關鍵字

茶湯品質 ； 義式咖啡機 ； 定量描述分析

並列摘要

The objective of this study was to investigate the effects of espresso extraction compared to the hot water infusion (HWI) method on the color, pH, caffeine, total catechins, total free amino acids and sensory qualities. Jin-Syuan tea from Nantou County was prepared to make partially-fermented tea (oolong tea). Tea samples were then ground, shieved and categorized into groups with big (＞30 mesh) and small (＜30 mesh) particle sizes before brewing. The results indicated that there is no difference among treatments in brightness of oolong tea (p＞0.05). Caffeine contents by espresso extraction was significantly lower than those from the HWI method (p ＜ 0.05); Total catechins and free amino acids by espresso extraction were significantly higher than those from the HWI method. Sensory quantitative description analysis (QDA) indicated that among attributes of appearance, the espresso tea presented better clarity (p＜0.05) than HWI tea; small-sized espresso tea showed darker yellow color than any other groups. Among attributes of aroma, the small-sized espresso tea presented stronger (p＜0.05) roasted and refreshing notes; the big-sized espresso tea showed lower intensity of (p＜0.05) roasted and grassy-like notes. Among attributes of flavor, the big-sized espresso tea were less (p＜0.05) astringent and bitter than the other groups; Among attributes of aftertaste, savory strength by espresso extraction was significantly stronger than that from the HWI method (p＜0.05). In conclusion, espresso extraction with big-sized tea particles was considered an ideal method to have better sensory qualities.

並列關鍵字

Tea property ； espresso ； quantitative description analysis