双波长法测定薯芋类农产品中直链淀粉和支链淀粉的含量

目的:建立薯芋类农产品中直链淀粉和支链淀粉的双波长测定法，为品种选育、品质分级、加工应用和标准制定等提供基础数据。方法:研究了直链淀粉和支链淀粉的吸收光谱图，确定二者的最大吸收波长及参比波长。优化了分散剂、乙酸加入量等显色条件及测定条件。结果:直链淀粉标准曲线方程为:y=0.0259x?0.0051，R2=0.9994，线性范围0~33 μg/mL；支链淀粉标准曲线方程为:y=0.0031x+0.0167，R2=0.9965，线性范围0~111 μg/mL。直链淀粉的检出限为0.093 μg/mL，定量限0.28 μg/mL；支链淀粉的检出限为0.079 μg/mL，定量限0.24 μg/mL，直链淀粉回收率为90.0%~100.0%；支链淀粉回收率为88.0%~108.0%。结论:双波长法简单易行，结果准确可靠，适用于薯芋类农产品中直链淀粉和支链淀粉的分析检测。

Determination of Amylose and Amylopectin Contents in Yam and Taros by Dual-Wavelength Spectrophotometry

Objective: The paper aims to establish a dual-wavelength spectrophotometry method for the determination of the content of amylose and amylopectin in yam and taros, and to provide basic data for variety selection, quality grading, product processing and standard formulation. Method: The spectrum of amylose and amylopectin were studied and the maximum absorption wavelength and reference wavelength were determined. The color conditions such as dispersant and acetic acid and measuring conditions were optimized. The absorbance values of the color complexes were determined. Result: The standard curve equation of amylose was y=0.0259x?0.0051, R2=0.9994, with the linear range of 0~33 μg/mL. The standard curve equation of amylopectin was y=0.0031x+0.0167, R2=0.9965, with the linear range of 0~111 μg/mL. The limits of detection and quantification of amylose were 0.093 μg/mL and 0.28 μg/mL respectively. The limits of detection and quantification of amylopectin were 0.079 μg/mL and 0.24 μg/mL, respectively. The recovery of amylose was 90.0%~100.0%. The recoveries of amylopectin were 88.0%~108.0%. Conclusion: The dual-wavelength spectrophotometry method was simple and feasible, accurate and reliable. It was suitable for the determination of amylose and amylopectin in yam and taros.