糖粉产品中淀粉抗结剂的含量测定

Determination of Starch Anti-caking Agent Content in Powdered Sugar

国家食品标准中测定淀粉的方法主要是酶水解法和酸水解法,都不适于测定糖粉中作为抗结剂使用的淀粉含量。本文采用碘显色可见分光光度法测定糖粉中抗结剂含量,将糖粉直接溶解、加热糊化、碘液显色,采用标准曲线法,基于在590 nm波长处的吸光度测定计算出抗结剂的含量。由于糖粉抗结剂淀粉和用来制作标准曲线的淀粉标样是不同来源的玉米淀粉,分子结构有所差别,其碘复合物的吸收光谱虽形状变化相同,但存在差异。本文利用它们的淀粉-碘复合物的最大吸光值之比值作为校正系数,解决待测样品与标准品的玉米淀粉不同所产生的系统偏差,测得样品抗结剂含量为3.96%。

Determination methods of starch in national food safety standards of China are mainly enzymatic hydrolysis and acid hydrolysis methods,which are not suitable for determination of the starch content added to powdered sugar as anti-caking agent.In this paper,the method of determining the content of anti-caking agent in sugar powder by iodine complex spectrophotometry was studied.The sugar powder was directly dissolved,heated and gelatinized and was developed with the addition of iodine liquid.The standard curve method was used to calculate the content of the anti-caking agent at the wavelength of 590 nm.The starch in powdered sugar is a bit different from the maize starch used as standard sample to produce the standard curve.The absorption spectrum of these two starch-iodine complex has the same shape but different absorbance due to different sources of maize starch,which indicate different molecular structure.In this paper,the ratio of the maximum absorbance of the starch-iodine complex was used as the correction coefficient to solve the system deviation of the tested sample and the standard sample.The content of starch in powdered sugar was 3.96%.