甘薯中淀粉测定方法的比较与优化

淀粉含量的测定方法多种多样，但是关于甘薯淀粉的测定方法，目前尚无统一标准。本研究通过对甘薯干基获得方式，淀粉水解方式以及还原糖测定方式三个主要因素对甘薯淀粉含量测定结果的影响进行探究。实验发现，冷冻干燥样品测定的淀粉质量分数比高温干燥样品显著高出38.43%，酸水解方式比酶水解显著高出6.51%。还原糖测定方法中，DNS1和DNS2测定方法分别比斐林试剂滴定法显著高出29.67%和9.47%，DNS1比DNS2测定方法显著高出20.04%。不同水解-还原糖测定方法纯淀粉回收率和加标淀粉回收率均处于95%~105%之间，变异系数均小于2%，准确度和精确度符合质控规范。综合分析表明，冷冻干燥酶水解DNS1法测定甘薯淀粉含量具有最高的准确性和精确性，冷冻干燥酸水解DNS2法则具有最佳的实用性和方便性。

Comparison and Optimization of Detection Methods for Starch in Sweetpotatos

There are several ways to determine starch, but no unified standard for the determination of the sweetpotato starch. In the paper, the effects of three experimental factors- drying mode, hydrolysis method and reducing sugar test method on the starch content of sweetpotato were studied. It was found that the tested starch content of freeze-drying samples was 38.43% significantly higher than that of high-temperature drying samples, and that of acid hydrolysis was 6.51% significantly higher than that of enzyme hydrolysis. Among the reducing sugar determination methods, the methods of DNS1 and DNS2 were significantly higher than the Philin reagent titration method by 29.67% and 9.47%, respectively, and DNS1 was significantly higher by 20.04% than DNS2. The recoveries of pure starch and spiking samples of different hydrolysis-reducing sugar determination methods were between 95%~105%, and the coefficient of variation was less than 2%, and the accuracy and precision were in line with the quality control standard. Comprehensive analysis showed that the enzymatic hydrolysis and DNS1 method was the highest accuracy and precision in the determination of freeze-drying sweetpotato starch content, the acid hydrolysis and DNS2 method was the best practicality and convenience.