官能团保留指数鉴别掺淀粉糖浆蜂蜜的研究

Detecting Starch Syrup in Adulterated Honey via Retention Index

研究了利用官能团保留指数法(Kovats index)鉴别掺淀粉糖浆的假蜂蜜。蜂蜜样品溶于水后用凝胶(Bio-Gel?P-2 Gel)体积排阻法去除样品中果糖、葡萄糖,将寡糖富集后直接经阴离子交换色谱电化学检测器检测。直链麦芽寡糖是由葡萄糖单体缩合而成的寡糖,类似正构烷烃,将麦芽寡糖(二糖~七糖)标准样品色谱峰作为对照峰,将麦芽四糖、五糖、六糖、七糖的保留指数分别设为400、500、600、700,根据样品获得的色谱峰的保留时间计算官能团保留指数值,结果表明,在添加果葡糖浆的麦芽糖混标样品、掺有果葡糖浆的纯蜂蜜及部分市售蜂蜜样品均出现相同的官能团保留指数值,而纯蜂蜜样品不存在此现象,据此可判断蜂蜜是否掺假,灵敏度可达1%。利用该结果对已知掺假的蜂蜜进行验证,结论符合。

The use of retention index(Kovats index) to detect adulteration of honey with starch syrup was studied. After dissolving the honey sample in water, fructose and glucose were removed by Gel(Bio-Gel ? Gel P-2) size-exclusion, oligosaccharides were concentrated, separated, and directly identified by anion-exchange chromatography using an electrochemical detector. Linear maltooligosaccharides are formed by condensation of glucose monomers, similar to n-alkanes. Using the chromatographic peaks of maltooligosaccharide(maltose to maltoheptaose) standards as reference, the retention indices of maltotetraose, maltopentaose, maltohexaose, and maltoheptaose were set at 400, 500, 600, and 700, respectively, while the retention index value of sample peak was calculated based on the retention time. The results showed similar functional retention index values for maltose standard samples as compared with fructose syrup, pure honey containing fructose syrup, and in some commercial honey samples, while they were not found in pure honey samples. This approach can be used to detect adulteration of honey with 1% sensitivity, and was validated using deliberately adulterated honey samples.