茶儿茶素-香草醛酸性试剂检测方法的研究

atechins are the mainly functional and dominant flavor compounds in tea. Vanillin colorimetric method is usually used to detect catechins content, but its accuracy has been questioned. Solvent extraction, TLC and HPLC analysis were adopted to investigate the specificity and accuracy of reaction between vanillin-acid reagent and catechins. The results demonstrated that significant differences existed in the reactions of vanillin-acid reagent with different substances, among of which catechins had the highest sensitivity, lower in flavonols and flavanonols, and lowest in tea saponin. Factors influencing the reactions of vanillin-acid reagent with catechins, including the kinds of acid, acid concentration, reaction temperature and reaction time were further investigated. The results suggested that a sensitive, simple and relatively specific method to analyze catechins content should be performed by using 1% vanillin-HCl reagent and reacting for 5 minutes under room temperature. Catechins content could be calculated with the formula of Y(A505nm)= aX(μmol/ml)+b.