气相色谱法测定魔芋食品中葡甘聚糖及淀粉含量

Determination of Glucomannan in the Konjac Food by Gas Chromatography

建立了魔芋食品及魔芋粉中葡甘聚糖和淀粉含量的测定方法。样品酸水解,水解液中加入肌醇作为内标,浓缩干燥后,进行肟化反应与乙酰化反应。糖腈乙酰酯衍生物进行GC分析,内标法定量。结果表明,KGM单糖成分经衍生化能得到较好的色谱分析结果,采用肌醇作为内标定量分析,校正了分析过程系统误差,能准确测定葡萄糖和甘露糖的含量,以KGM分子中甘露糖和葡萄糖残基的摩尔比,及甘露糖和葡萄糖含量分别计算出葡甘聚糖和淀粉的含量。葡甘聚糖的测定结果排除了淀粉等其他糖类的干扰,结果准确可靠。

The method for quantitative determination of glucomannan and starch in the konjac food or konjac powder by GC was developed successfully. The sample was hydrolyzed with HCl. Inositol added as inter standand, the monosaccharides of glucomannan （mannose and glucose） were derivated with 1-methyimidazole as acetic anhydride used as reagent for oximiz vent and catalyst, hydroxylamine hydrochloride and ation and acetylation, respectively. The products of the derivation reaction were separated effectively by GC, detected by FID detector. The result shows that glucomannan and starch in the konjac food could be quantitatively determined.