香草醛/硫酸比色法测定两种原花色素含量的比较

分别选取儿茶素、葡萄籽原花青素、沙棘籽原花色素为基准物质,考察了三者与香草醛/硫酸反应影响因素的异同,优化了各自的测定条件,结果表明,儿茶素、葡萄籽原花青素和沙棘籽原花色素与香草醛反应动力学有显著差异。儿茶素的适宜反应条件为:30℃反应5min(测定波长500nm),葡萄籽原花青素的适宜反应条件为:20℃反应5min(测定波长500nm);沙棘籽原花色素适宜反应条件为:30℃反应15min(测定波长505nm);反应体系为:1ml样品甲醇溶液加入2.5ml 1%香草醛的甲醇溶液和2.5ml 5mol/L硫酸的甲醇溶液。

Comparison of Vanillin Assay for Two Different Proanthocyanidins

Vanillin assay reaction conditions were examined and compared for determining proanthocyanidin with catechin and purified proanthocyanidins chosen from grape seed and sea buckthorn seed as reference standards respectively.Several param-eters mostly affecting the precision and accuracy of vanillin assay were optimized.The results showed that the kinetics of the three type reactions were markedly different.The critical evaluation of vanillin assay was summarized up as follows:for catechin the reaction can be carried out at 30℃ for 5 minutes(measured at 500 nm);for grape seed procyanidins the reaction can be carried out at 20℃ for 5 minutes(measured at 500 nm);and for sea buckthorn seed proanthocyanidins the reaction temperature can be controlled at 30℃ while the reaction time fixed at 15 min(measured at 505 nm).The reaction medium comprise 1 ml of sample,2.5 ml of vanillin solution in methanol and 2.5 ml of 5 mol/L H2SO4 in methanol.