分光光度法测定大米直链淀粉含量的误差分析

Analysis on Error in Determining Amylose Content of Rice by Spectrophotometry

为了更准确的测定直链淀粉含量,在现有国家标准的基础上,探讨了直链淀粉测定过程中脱脂次数、酸度、碘的添加量、显色时间对吸光值的影响。结果表明:碘的加入量和显色时间对试验误差影响较大。碘的加入量应准确控制在1.0±0.1mL,大于1.1mL吸光值偏高,小于0.9mL吸光值偏低。实验过程中同批样品显色时间应控制在2h以内,以减少实验误差。脱脂次数和酸度对测定误差影响较小。

In order to accurately measure amylose content,the effect of degreasing,acidity,addition of iodine and chromogenic time on the absorbance value was investigated on the basis of the existing national standards.The results showed that addition of iodine and chromogenic time had a great impact on the experimental error.Iodine＇s adding amount should be accurately controlled between 1.0±0.1mL,greater than 1.1mL resulted in higher absorbance value,less than 0.9mL induced lower absorbance value.In order to reduce experimental error,chromogenic time for the same batch of samples should be controlled within 2hours.Degreasing times and acidity had little effect on measuring error.