影响玉米淀粉质量分数检测结果的因素分析

FACTORS INFLUENCING CORN STARCH CONTENT MEASUREMENT

运用单波长、双波长2种比色法对淀粉质量分数w进行测定,实验结果发现,后者更优,因其可有效排除其他物所造成的影响.直链淀粉波长在500和600nm、支链淀粉波长在550和680nm的条件下,当溶液pH值接近3.5、淀粉与碘化合物的反应时间在20min、标准曲线与样品测定环境温度控制在5℃温差时,淀粉w分析误差均达最小值.

Contents of amylose and amylopectin are important parameters to judge corn starch quality. Two spectrophotometric methods （single and double wavelengths） were compared and the latter was found to be better suited because it was not affected by other components. Analytical error was small when optical density was measured from 500 to 600 nm for amylose, from 550 to 680 nm for amylopectin. Optimal pH was at 3.5, optimal reaction time was found to be 30 min.