以線上光學檢測系統進行單寧酸之定量分析

Abstract

摘要 本研究針對茶品中單寧酸總量檢測與茶品中單寧酸與蛋白質凝集造成澀味感受進行探討，分別建立了螢光消光流動系統與光散射流動系統。 在螢光消光流動系統中，能有效避免維他命C 與溫度變化的干擾，並擁有對單寧酸高度選擇性與檢測靈敏等優點。在茶品實測的應用面上，本系統的線性範圍為濃度0.0-1.0 mg/ml，R2 ＝ 0.9928，且分析結果與日本公定法具有高度相關性（R2 ＝ 0.9803）。 在光散射流動系統中，SDS 洗劑清洗程序能有效的改善訊號之背景值漂移與重複性不佳等實驗誤差，徹底清除吸附於管壁的單寧酸與BSA 之凝集分子，成功建立一套能即時檢測與即時清洗的線上感測系統。系統檢測下限為20 μg/ml，上限為300 μg/ml。此系統能有效以單寧酸與蛋白質的凝集情形得知澀味等生理活性。

Two on-line systems have been setup in this research for determination of tannic acid content in green tea infusion and biological activation of protein and tannic acid aggregation in tea. In fluorescence quenching method with flow-injection system which has been applied for detection of real samples within a linear concentration range of 0.0-1.0 mg/ml and a R2 of 0.9928. The method is immune from the interference of the coexisting ascorbate in green tea infusion and temperature changing, and the analytical results were verified by Japanese official analytical method, ferrous tartrate method. In light scattering method with flow-injection system, experiment error such as drift of baseline and lacking of reproducibility can be solved effectively by cleaning procedure with SDS reagent for the effective removal of residual aggregation particles by tannic acid and BSA. Therefore, an on-line detection system with real time detection and cleaning ability have been setup successfully. The range of detection is 20-300 μg/ml, and astringent activation in tea can be known by aggregation of tannic acid and BSA