绿茶汤色分析

Analysis of Liquor Color of Green Tea

采用色差分析和感官审评的方法对10种绿茶汤色进行分析,结果显示,品茶师间对绿茶评分与评价呈现较高度一致,差异性较小。色差分析绿茶汤色各组间明亮度(L)、茶汤绿度(a)和茶汤黄度(b)均具有较好的一致性,亦存在差异;但绿茶汤色各组间色差衍生指标a/b具有高度一致性。统计分析显示:品茶师茶汤评分与茶汤明亮度(L)和茶汤黄度(b)相关性较小,与茶汤绿度(a)相关性较大;而与色差衍生指标a/b达极显著相关。应用逐步回归对色差的衍生指标色相(a/b)进行绿茶汤色感官评分表征,相关性均达极显著,其决定系数均可达80%以上。应用二次多项式逐步回归对色差亮度(L值)和色差的衍生指标色相(a/b)进行绿茶汤色感官评分表征,相关性均达显著以上,其决定系数均可达95%以上。文中还对绿茶汤色的表述进行了讨论。

The liquor colors of ten green teas were analyzed by color difference and sensory evaluation. The results showed that there were high coherence and less discrepancy between taster score and remark of liquor color of green tea. High coherence and less discrepancy between L^＊ value （an indicator of light and dark）, a^＊ value （the redness-greenness indicator）, and b^＊ value （the yellowness-blueness indicator） of the control group liquor color of green tea were also observed; and there were positively and significantly coherence between a^＊/b^＊ value （a derivation indicator of the color difference） of the opposite group liquor color. The statistical analysis showed that taster score were less correlated with L^＊ and b^＊ value of liquor color of green tea; were more correlated with a^＊ value and were positively and significantly correlated with a^＊/b^＊ value. By applying the stepwise regression, taster score were represented as a^＊/b^＊ value in liquor color of green tea, the correlation was positive and significant, the coefficient of determination was more than 80 %. Using the quadratic polynomial stepwise regression, taster score were represented as L^＊ value and a^＊/b^＊ value in liquor color of green tea, the correlation were significant or positive and significant; the coefficient of determination were more than 95 %. And the expression of liquor color of green tea was discussed.