A Simple and Rapid Colorimetric Method for the Determination of Amylose in Starch Products

A method for the determination of the amylose content in starch has been developed which is based on the colorimetric measurement of the iodine complexes formed with amylose and amylopectin. The method requires measurement at only one wavelength and avoids the use of harsh dispersants for the starch. Dimethyl sulphoxide is used as the dispersant and a wavelength of 600 nm can be used for measurement of the amylose content of starches from different botanical sources. A linear relationship was obtained between absorbance and amylose concentration for mixtures of amylose and amylopectin standards, and this forms the basis of the determination. The method is rapid, simple, accurate and does not require the use of multi-component analysis of spectra, since a wavelength is chosen that suits the particular starch being analysed. It can be adapted to a micro-scale method if necessary.