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題名 | 萎凋溫度與濕度對白茶品質之影響(1)--失水曲線=Effects of Withering Temperature and Humidity on the Quality of White Tea (1)--The Dehydration Curve |
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作者 | 林金池; 陳世雄; | 書刊名 | 臺灣茶業研究彙報 |
卷期 | 16 1997.05[民86.05] |
頁次 | 頁1-17 |
分類號 | 473.4 |
關鍵詞 | 茶; 萎凋; 溫度; 時間; 失水曲線; 濕度; Tea; Withering; Temperature; Humidity; Time; Dehydration curves; |
語文 | 中文(Chinese) |
中文摘要 | 本試驗目的在探討控制萎凋溫度與濕度對白茶製造過程茶葉失水曲線之影響。自 1994 年秋季至 1995 夏季,採摘臺灣省茶業改良場十年生臺茶 17 號一心二葉茶菁, 在溫 、濕度控制之萎凋室進行試驗。茶菁採摘後分別以三種溫度 (18、25、32 ℃ ) 與三種濕度 (40、60、80%),進行 60 小時萎凋試驗。 期能藉由不同處理茶葉在萎凋期間失水變化差異 , 探討白茶最佳萎淍條件,供改善白茶製造技術之參考。 試驗結果顯示,春茶茶菁在低溫 (18 ℃ ) 高濕 (80%) 環境萎凋,茶葉失水較和緩,失水曲線為 Y=75.4-0.164X-0.007X �� (X 為萎凋時間 )。但在高溫 (32 ℃ ) 低濕 (40%) 環境萎凋,則茶葉失水速率比低溫高濕 快三倍以上 (Y=82.75-1.434X-0.003X �� )。夏、秋茶也有類似的結果。茶菁萎凋期間若急 速失水會導致葉綠素破壞分解,茶葉內含物質轉化不足,萎淍 30 小時後葉部紅變,白茶外 觀及品質變劣。萎凋溫度以接近茶芽生長期間溫度為佳,臺灣桃園茶區春茶生育期間溫度月 平均溫度為 15.2 ℃,夏、秋茶為 25~27 ℃,因此, 建議春茶以 18 ℃, 夏、秋茶以 25 ℃,在相對濕度 80% 左右,萎凋 40~50 小時,可望生產較佳品質之白茶。 |
英文摘要 | Experiments were conducted from the fall of 1994 through spring and summer of 1995 to investigate effects of withering temperature, and humidity on the quality of white tea. Young shoots of a bud with two leaves harvested from ten-year-old tea (cultivar TTES17) bush, which growing on the Taiwan Tea Experimental Station, were used for the withering experiments. Splitplot design with three replications were applied to three crops of tea under controlled temperature and humidity. Three levels of withering temperature, 18, 25, and 32 ℃ consisted as the main plot. The subplot were three levels of relative humidity, 40, 60, and 80. Dehydration curves of tea shoots during 60 hours withering were recorded before oven dry. Experimental results showed that tea leaves withering under low temperature (18 ℃ ) with high humidity (80%RH) had a slow drying rate (slope) of dehydration curve (water content, X denote withering time in hours). When tea leaves withering under a higher temperature (32 ℃ ) with lower humidity (40%RH), the drying rate increased about 3 times faster than that under low temperature with high humidity, where the dehydration curve was. The dehydration curves of the summer and fall tea showed the same results. Rapid drying caused degradation of chlorophyll and resulted in redness of tea leaves, which led to poor quality of white tea. Experimental results showed that withering the tea leaves at the temperature close to its growth environment gave a better quality white tea. Month mean air temperature was 15.2 ℃ at Taoyuan area during the growth period in the spring, and was about 25-27 ℃ forthe summer and fall. It was suggested that tea leaves withering under low temperature with high humidity, such as 18 ℃ for the spring, and 25 ℃ for the summer and fall, with 80% relative humidity to 40-50 hours, are essential to a better quality of white tea. |
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