不同水样水质、热稳定性及其对白茶茶汤理化性质的影响

Effects of Water Qualities and Thermal Stability of Different Water Samples on the Physicochemical Properties of White Tea Infusion

为了解不同水样水质、热稳定性及其对白茶茶汤理化性质的影响,以探明有利于白茶汤色特征形成的水质类型和理化条件,分别选择自来水、蒸馏水及市售矿泉水、纯净水、泡茶专用水等共8个水样与10个白茶茶样为供试对象,测定和比较了各试验水样煮沸前后水质指标及其对白茶茶汤pH值、L值、-a/b值、E值与汤色等的变化。结果表明:各水样经煮沸后,偏硅酸、Mg^2+、Na^+、K^+含量趋于减少,pH值趋于升高,其中纯净水、蒸馏水pH值增幅达0.25~0.48;冲泡同一茶样茶汤之间,纯净水与矿泉水的L值、-a/b值、E值差异均达到显著水平(P<0.05);茶汤pH值和-a/b值与白茶汤色变化、优劣关系密切,-a/b值和pH值分别在0.00~0.30与6.00~7.00的茶汤能较好表现出明亮杏黄或浅杏黄的白茶汤色特征;本试验水样中,矿泉水冲泡的汤色总体优于其他水样。

In order to understand the water quality,thermal stability of different water samples and their effects on the physical and chemical properties of white tea infusion,and to find out the water quality types and physical and chemical conditions that are conducive to the formation of color characteristics of white tea infusion,eight water samples and ten white tea samples were selected as the test objects,including tap water,distilled water,commercial mineral water,purified water and tea making water,the water quality indexes of water samples before and after boiling and their effects on pH value,L value,-a/b value,E value and color of white tea infusion were determined and compared.The results showed that after boiling,the contents of metasilicic acid,Mg^2+,Na^+,and K^+ tended to decrease,but the pH value showed an opposite trend,among which the pH values of pure water and distilled water increased by 0.25~0.48;the differences of L value,-a/b value,E value between pure water and mineral water were significant(P<0.05);the pH and-a/b values of tea infusion were closely related to the color change and quality of white tea infusion,and the tea infusion with-a/b value of 0.00~0.30 and pH value of 6.00~7.00 could better show the color characteristics of bright apricot yellow or light apricot yellow;in this experiment,the infusions color brewed with mineral water were generally better than other water samples.