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題 名 | 培火條件對烏龍茶茶湯品質之影響=Effect of Firing on the Quality of Oolong Tea Infusion |
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作 者 | 陳清泉; 尤新輝; 孫智斌; 程竹青; | 書刊名 | 食品科學 |
卷 期 | 23:2 1996.04[民85.04] |
頁 次 | 頁308-319 |
分類號 | 473.4 |
關鍵詞 | 烏龍茶; 焙火; 多元酚; Oolong tea; Firing; Polyphenol; |
語 文 | 中文(Chinese) |
中文摘要 | 本研究主要探討焙火對低價位烏龍茶茶湯品質之影響。粗製茶經焙火後茶湯顏色朝向紅黃色發展,茶湯經超高溫短時間加熱後,外觀顏色變暗變紅。粗製茶焙火後游離胺基酸含量明顯減少,總游離胺基酸約損失10~20%。烏龍茶之游離胺基酸含量最高者為茶胺酸,其它含量較高的胺基酸為glycine,glutamic acid及aspartic acid等。烏龍茶之咖啡因及兒茶素類含量隨焙火時間之增加而增加,兒茶素類化合物中以EGC、ECG、EGCG等三種增加幅度較大,焙火對茶湯中EC含量則無明顯效應。烏龍茶經過超高溫短時間加熱後,兒茶素含量明顯增加約1倍,EGCG含量則明顯下降,EGC含量亦有減少趨勢,EC則明顯增加,ECG含量變化不大。粗製茶焙火後,hexanal及5, 5-dimethylhexanal等具青草味的揮發性成分含量明顯下降,隨焙火時間之增加其含量下降越多。茶葉在焙火時也會進行梅納反應而產生furan, pyrazine, furfural等類的揮發性成分,此外,indole含量在焙火時有顯著降低。在感官品評方面,經過焙火後青草味會大幅度降低,茶香味與烘焙香味得分則隨焙火時間之增加而增加,苦味及澀味在統計上並不顯著(p<0.05)。 |
英文摘要 | The effect of firing of oolong tea upon the quality of tea infusion was investigated. Hunter b value of the oolong tea infusions extracted with 1% oolong tea, which were firing at 120℃ for 1~5 hours, increased significantly as the firing time increased. The color of oolong tea infusions also became darker after UHT pasteurization. Free amino acid contents of oolong tea infusions, which was comprised mainly of theanine, glycine, glutamic acid and aspartic acid, were lost about 10~20% during firing. The contents of caffeine and catechins of oolong tea infusions increased as the firing time increased. Among the catechins, the contents of EGC, ECG and EGCG increased, while EC remained unchanged after firing. The catechin contents of oolong tea infusions were also changed after UHT pasteurization. The contents of catechin and EC increased, while EGCG and EGC decreased significantly. ECG was quite stable during UHT pasteurization. The contents of hexanal and 5,5-dimethyl-hexananl, both of them were "grassy" top note, decrease significantly as the firing time increased. Typical products or intermediates from Maillard reaction, such as furan, pyrazine and furfural, were also found in the oolong tea infusions. Indole decreased significantly during firing. Sensory score of grassy note of oolong tea infusions lowered significantly after firing, on the other hand, sensory scores of tea flavor, roasty, bitterness and astringency showed an increasing tendency as firing time increasing, but were not significant at 95% confidental limit. |
本系統中英文摘要資訊取自各篇刊載內容。