介绍了以对-二甲基氨基肉桂醛（DMAC）为显色剂测定原花青素含量的分光光度法，并测定了山竹果皮、花萼和果肉中原花青素的含量。DMAC溶液与儿茶酚反应后60 min内吸光度测定显示，两者形成的缩合物吸光度在15~35 min内比较稳定，适宜测量。DMAC溶液配制后，-18 ℃暗处保存2 d、6 d后使用与当天使用的测定结果有明显差异，因此建议当天配制使用。另外，香草醛法与DMAC法进行了比较分析，DMAC法测定的山竹原花青素含量低，但其灵敏性远高于香草醛法。实验测得，以儿茶酚为标准品得到的线性方程为y = 0.0937x-0.0029（R2=0.9993）；山竹中果皮、花萼和果肉中原花青素的含量分别为：4.23±0.24 mg/g，0.85±0.02 mg/g，0.53±0.03 mg/g（以儿茶酚计）。

4-(Dimethylamino)cinnamaldehyde (DMAC) was introduced as a chromogenic agent to determine proanthocyanidins by spectrophotometry, and the content of proanthocyanidins in rind, calyx lobes and aril of mangosteen were detected by DMAC assay. The condensation compound of DMAC and catechin was stable and can be measured in 15~35 min after reaction, while DMAC solution is suggested to be used fresh daily. Vanillin assay was also conducted in determining mangosteen proanthocyanidins, which showed a higher content but less sensitivity compared with DMAC assay. The standard curve was y = 0.0937x - 0.0029（R2 = 0.9993）in DMAC assay. Proanthocyanidins content in rind, calyx lobes and aril of fresh mangosteen were 4.23±0.24 mg/g, 0.85±0.02 mg/g and 0.53±0.03 mg/g, respectively, using catechin as standard.

“十二五”国家科技支撑计划项目(2012BAD031B03)