Abstract: The optimized method for extraction and purification of Canna edulis Ker. starch was determined by orthogonal design and then validated by the experiment, and the maximum content of the starch was obtained when ratio of sample and liquid was 1:2, along with 2 hours of rest time and four times of washing. Then, the amylose of Canna edulis Ker. was extracted with the method of hot alkaline, and purified through n-butanol and isoamyl alcohol crystallization again and again. At last, absorption spectrum of iodin-amylose compound was scanned from 500 to 800 nm using UV spectrometer. The amylose content was determined by the method of hot alkaline and Fehling Reagent and iodine combined content of the amylose was determined by electrometric titration. The result showed that maximum absorption spectrum of the iodin-amylose compound locates at 600 nm and the values of content and Iodine combined content of the amylose obtained are 87.14% and 10.4, respectively. In addition, the content of amylose in the Canna edulis Ker. starch is further determined as 77.94% through standard curve using the obtained amylose starch and amylopectin starch of corn as standards. This study can make a contribution to basic study of Canna edulis Ker. starch at molecular level.

Key words: Canna edulis Ker., starch, amylose, process optimization, content determination