不同泡次对福建白茶内含物溶释的影响

刘乾刚; 陈曦

doi:10.19303/j.issn.1008-0384.2020.10.015

摘要:

目的探讨白茶不同泡次茶汤内含物溶释的特点和规律，为白茶工艺、品质改进及科学饮茶提供理论依据。

方法选择2个茶树品种不同茶叶等级共4个茶样，按白茶审评方法冲泡茶汤，测定3泡次内含物的溶出量、溶出率。

结果（1）4个茶样各内含物3泡总溶出量均值为多酚类（9.56 g·hg⁻¹）＞儿茶素（4.78 g·hg⁻¹）＞可溶性糖（4.26 g·hg⁻¹）＞茶褐素（3.98 g·hg⁻¹）＞茶红素（3.59 g·hg⁻¹）＞咖啡碱（3.26 g·hg⁻¹）＞氨基酸（2.38 g·hg⁻¹）＞黄酮（0.45 g·hg⁻¹）＞茶黄素（0.12 g·hg⁻¹）；3泡总溶出率均值为咖啡碱（78.95%）＞黄酮（70.71%）＞氨基酸（66.69%）＞茶褐素（63.98%）＞茶红素（61.97%）＞多酚类（55.77%）＞可溶性糖（53.27%）＞儿茶素（40.42%）＞茶黄素（31.34%），表没食子儿茶素没食子酸酯（EGCG）、茶氨酸（The）分别为43.31%、63.23%；（2）第1至第3泡溶出率，除茶红素、可溶性糖外，其余内含物呈下降趋势，其中咖啡碱、氨基酸、黄酮第1泡溶出率最高，其在4个茶样第1泡的溶出率均值分别为37.13%、31.54%、29.73%，且3泡总溶出率也高；（3）同一茶样3次冲泡中，水浸出物、多酚类、咖啡碱、黄酮、茶红素溶出量的增减程度均达到显著差异（P＜0.05）水平，而咖啡碱、氨基酸溶出率逐次下降明显，降幅达9%以上；（4）不同茶样相同泡次之间，内含物溶出率总体上未表现出茶叶品种和等级之间的规律性差异。

结论除茶红素、可溶性糖外，其余内含物溶出量、溶出率为第1泡＞第2泡＞第3泡，但内含物之间的溶释效率存在明显差异，咖啡碱、氨基酸、黄酮等溶出较快，而多酚类、儿茶素及EGCG、The等高含量内含物或组分并未充分溶释，尤其是儿茶素、EGCG和表儿茶素没食子酸酯（ECG），其3泡总溶出率均低于50%。

Abstract:

Objective The dissolved components in the brews of Fujian white teas were investigated.

Method 4 local white tea products of 2 cultivar varieties and 2 quality grades were brewed by the standard procedures for sensory evaluation on white tea. The components in the 3 series of brewed teas were analyzed.

Result (1) After 3 series of brewing the average total dissolved amounts of the components were 9.56 g·hg⁻¹ for polyphenol, 4.78 g·hg⁻¹ for catechin, 4.26 g·hg⁻¹ for soluble sugar, 3.98 g·hg⁻¹ for theabrownine, 3.59 g·hg⁻¹ for thearubigin, 3.26 g·hg⁻¹ for caffeine, 2.38 g·hg⁻¹ for amino acid, 0.45 g·hg⁻¹ for flavone, and 0.12 g·hg⁻¹ for theaflavin, the average total dissolved rates of the components were 78.95% for caffeine, 70.71% for flavone, 66.69% for amino acid, 63.98% for theabrownine, 63.23% for theanine, 61.97% for thearubigin, 55.77% for polyphenol, 53.27% for soluble sugar, 43.31% for EGCG, 40.42% for catechin, and 31.34% for theaflavin. (2) Except for thearubigin and soluble sugar, all the other components decreased in their dissolved amounts and rates from the 1^st to the 3^rd brewing, among which caffeine,amino acid and flavone showed the highest average dissolved rates of 37.13%,31.54%,29.73% respectively in the 1^st brewing. (3) Polyphenol, caffeine, flavone or thearubigin differed significantly (P＜0.05) between its dissolved amounts of 3 series of brewing of the same sample.The dissolved rates of caffeine and amino acid decreased significantly by more than 9% in one more brewing, while the dissolved rates of the components generally did not show regular differences between the varieties and the grades.

Conclusion The dissolved amounts and rates of the components tested, except for thearubigin and soluble sugar, declined from the 1^st to the 3^rd brewing. In 3 consecutive brewing, due to differences in solubility, caffeine, flavone and amino acid rapidly leached, polyphenol and theanine partly dissolved, and less than 50% of catechin, EGCG and ECG in the dry leaf dissolved in 3 brewings.

不同泡次对福建白茶内含物溶释的影响

Effects of Repeated Brewing on Dissolution of Fujian White Tea Components