Analytical and Testing Center, Beijing Normal University, Beijing 100875, China.
Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2011 Dec;28(12):1645-56. doi: 10.1080/19440049.2011.610035. Epub 2011 Oct 21.
A method for the determination of cyanidin-3-glucoside (red kernel colour, RKC) in various matrices, including carbonated soft drinks, fruit-based soft drinks, sugar confectionery and milk-based drinks, by high performance liquid chromatography (HPLC) based on UV-Vis detection (at 520 nm) have been developed. Pre-treatment procedures for various matrices have been optimised. For soft drinks, the pH values were adjusted to 2.0, and sugar confectionery and milk-based drinks were extracted with 30 and 50% methanol in 0.1% formic acid (pH ~ 2.5) aqueous solutions, respectively. The limits of detection for the established methods ranged from 0.2 mg/kg for soft drinks to 2.0 mg/kg for the sugar confectionery and milk-based drinks with the relative standard deviations lower than 7%, which satisfy the method performance requirements for quality control for the beverages. The stability of the colourant RKC under various thermal and pH conditions was investigated by quadruple time-of-flight mass spectrometry (Q-TOF-MS). The main colourant component of RKC, cyanidin-3-glucoside (Cyd-3-Glu), lost the glucose entity under thermal treatment. A new component was identified when RKC degraded under various pH conditions and a degradation pathway is proposed. The results will assist in understanding the degradation mechanism of the colourant Cyd-3-Glu.
建立了一种基于高效液相色谱-紫外可见检测（520nm）法测定各种基质（包括碳酸软饮料、水果软饮料、糖果和含乳饮料）中矢车菊素-3-葡萄糖苷（红色素，RKC）的方法。优化了各种基质的预处理程序。对于软饮料，将 pH 值调节至 2.0，对于糖果和含乳饮料，分别用 30%和 50%甲醇在 0.1%甲酸（pH~2.5）水溶液中提取。所建立方法的检出限范围为软饮料 0.2mg/kg 至糖果和含乳饮料 2.0mg/kg，相对标准偏差低于 7%，满足饮料质量控制的方法性能要求。通过四极杆飞行时间质谱（Q-TOF-MS）研究了 RKC 在各种热和 pH 条件下的稳定性。RKC 的主要着色剂成分矢车菊素-3-葡萄糖苷（Cyd-3-Glu）在热处理下失去葡萄糖单元。当 RKC 在各种 pH 条件下降解时，发现了一个新的成分，并提出了一个降解途径。研究结果将有助于了解着色剂 Cyd-3-Glu 的降解机制。
