紫外双波长法测定西藏马铃薯淀粉中直链淀粉和支链淀粉含量

Determination of amylose and amylopectin in Tibetan potato starch by ultraviolet dual wavelength method

目的:建立紫外双波长法测定西藏马铃薯淀粉中直链淀粉和支链淀粉的含量。方法:按照双波长测定的等吸收点作图法确定西藏马铃薯直链淀粉和支链淀粉测定波长分别为623、557 nm,参比波长分别为498、729 nm,对收集的11批次淀粉样品进行含量测定及分析。结果:直链淀粉、支链淀粉质量浓度分别在0~66、0~90μg·mL^(-1)范围内呈良好的线性关系(r=0.9999、0.9998),6份样品中直链淀粉和支链淀粉的平均加样回收率分别为102.8%(RSD=1.8%)、98.5%(RSD=2.2%),精密度(RSD=0.071%、RSD=0.31%)、重复性(RSD=0.26%、RSD=2.4%)、稳定性(RSD=0.14%、RSD=1.4%)均符合规定。西藏马铃薯淀粉中直链淀粉、支链淀粉含量分别为36.74%、45.87%,与市售马铃薯淀粉相比,西藏马铃薯淀粉的直链淀粉含量显著性增高(P<0.001),支链淀粉含量显著性降低(P<0.05)。结论:经方法学验证,该方法可用于西藏马铃薯淀粉的质量评价,西藏马铃薯淀粉与市售的马铃薯淀粉的直链淀粉、支链淀粉含量存在显著性差异,本法为西藏马铃薯淀粉的质量标准建立以及高值产品开发提供了实验依据。

Objective:To establish a dual-wavelength method for the determination of amylose and amylopectin in potato starch in Tibet.Methods:The determination wavelengths of amylopectin and amylopectin in Tibetan potato were 623 and 557 nm,respectively,and the reference wavelengths were 498 and 729 nm.The contents in 11 batches of starch samples collected were determined and analyzed.Results:The results showed that the mass concentration of amylose and amylopectin showed a good linear relationship(r=0.9999,r=0.9998)in the range of 0-66μg·mL^(-1)and 0-90μg·mL^(-1),respectively.The average recoveries of amylose and amylopectin were 102.8%(RSD=1.8%)and 98.5%(RSD=2.2%).The precision(RSD=0.071%,RSD=0.31%),repeatability(RSD=0.26%,RSD=2.4%)and stability(RSD=0.14%,RSD=1.4%)were all in compliance with regulations.The contents of amylose and amylopectin in Tibetan potato starch were 36.74%and 45.87%,respectively.Compared with the commercially available potato starch,the amylose content of Tibetan potato starch was significantly increased(P<0.001),while the amylopectin content was significantly decreased(P<0.05).Conclusion:The method is proved to be suitable for the quality evaluation of potato starch in Tibet.There are significant differences in the contents of amylopectin and amylopectin between potato starch in Tibet and potato starch in the market,which provides an experimental basis for the establishment of quality standards of potato starch in Tibet and the development of high-value products.