Extraction of pure amylose and amylopectin from canna starch and determination by spectroanalysis

The amylose and amylopectin from canna starch were separated and purified,and the purity of them were also characterized.Furthermore,a method of dual-wavelengths spectrophotometry was established,which was used to determine the content of amylose in canna starch.The amylose and amylopectin were separated from canna starch by n-butanol recrystallization method.The purity of amylose and amylopectin were characterized based on the optical absorption properties of the starchiodine complex.According to the principle of dual-wavelengths method,the content of amylose in canna starch was determined at the selected wavelength 617 nm and the reference wavelength 504 nm.The maximum absorption wavelength of the purified amylose and amylopectin were 630～645 nm and 548～554nm respectively,and the blue values of them were 1.167±0.209 and 0.122±0.001 respectively,which were all in the distribution range of the corresponding standard sample.It indicates that the purity of the amylose and amylopectin are high.And the linear relation between the content of amylose and absorbance was exist in the range of 0～80 mg/L(r=0.9998).The amylose and amylopectin are separated and purified successfully from canna starch by the n-butanol recrystallization method.And the purity of amylose and amylopectin are effectively characterized based on the optical absorption properties.Furthermore,as the advantages of easily operation and accuracy,the dual-wavelength method is used to determine of amylose in canna starch quickly and without the separation of the samples.