Determination of amylose and amylopectin in Tibetan potato starch by ultraviolet dual wavelength method
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=0.999 9,r=0.999 8)in the range of 0-66 μg·mL-1 and 0-90 μg·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 compli-ance 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.