|Title:||茶葉主要化學成分於製茶過程中之變化及其對品質之影響||Other Titles:||The Changes of Chemical Components of Tea during the Manufacturing Process and the Effects on Tea Quality||Authors:||張如華
|Keywords:||化學成分;製茶過程;茶葉品質;茶湯水色;chemical components;tea manufacturing process;tea quality;liquor color of tea||Issue Date:||Dec-1995||Publisher:||農業試驗所||Related Publication(s):||農業試驗所特刊第56號||Start page/Pages:||120-148||Source:||農特產品加工研討會專刊||Conference:||農特產品加工研討會
Proceeding of A Symposium on Processing of Agricultural Products
The changes of chemical components of tea during manufacturing process and the effects on tea quality were studied, the results showed as follows:
1. The catechins contents were decreased gradually during tea manufacturing process, and changes of EGCG and EGC contents were significantly.
2. Total amino acids during tea manufacturing process hadn¡¦t much change. Individually, theanine and glutamic acid were reduced. Others of free amino acid had tendency to increase.
3. Caffeine and theobromine during tea manufacturing process changed not much, but still decreased.
4. It reached significant negative correlation between ∆b and ∆E of tea liquor and contents of catechins during tea manufacturing process.
5. The results from the effect of solar-withering on paochung tea quality were positive. Nevertheless, unsolar-withering tea caused grassy odor; excessive solar-withering had inferior tea quality.
6. During manufacturing middle grade quality of paochung tea with machine, if controlled withering of tea shoots at 35℃, processing time of tea shoots could be shortened to 1/2. Moreover the quality of tea was found to be on a par with, or somewhat superior to those of the naturally withered tea.
7. From the correlation analysis of chemical components and taste, there were positive correlation between most of amino acid and taste scores; negative correlation between most of catechin and taste scores. In addition, the value of ∆b correlated with the scores of tea liquor reached significant negative correlation.
8. When the paochung tea roasted at l20℃ or above, the higher of roasting temperature and the longer of roasting time made tea quality worse, and the color of liquor changed to red and dull, the values of ∆a and ∆b increased, the chemical components (catechins, amino acids, reducing sugar) contents decreased.
|Appears in Collections:||農業化學組|
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