Correlation between Sensory Evaluation and Chemical Ingredients Related to Bitterness and Astringencyin Oolong Teas Prepared in Different Seasons

• Main Authors: Mei-Chun Liu, 劉美君
• Other Authors: Tze-Cheng Tzen
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/31972011159547612091

碩士 === 國立中興大學 === 生物科技學研究所 === 101 === Tea has been a kind of health beneficial drink for several thousand years in the East, and the sensory evaluation has also been regularly evaluated by professional panels in Taiwan in the past few decades. The quality as well as the price of oolong tea produced in different seasons varies significantly. In general, tea of spring and winter are better than those of summer and autumn. This research aimed to examine oolong tea produced in the four seasons from the same farm in the Mountain Ali area (Shihchuo, Taiwan). In the first part, tea samples were prepared according to the guideline of professional competition in Taiwan. In the second part, tea samples were prepared according to the general habits of continuous brewing. The data showed that the contents of catechins and caffeine of summer and autumn tea were higher than those of spring and winter tea. In addition, the results were in accordance with the sensory evaluation. The chemical analysis showed that the content of GCG subsequently increased in the tea samples of continuous brewing, and the relative astringency of EGCG and GCG were evaluated by SDS-PAGE analysis. Thus, the data showed that the GCG content was more likely associated with salivary proteins than EGCG, and it might be a key ingredient to cause oral astringency.