Amylose and amylopectin characterisation of potato leaf starch

Starches were isolated from potato leaves collected atv two times during the day, both at the middle of July and August. starch was extracted by successive washing steps with dimethylsulfoxide and precipitated with ethanol. The starch content of potato leaves varied between 2.9 and 12.9% (d.b.) in July and 0.6 and 1.5% in August. Scanning electron microscopy analyses of the four samples showed that starch granules had either an oval or round shape and did not exceed 5 microm. Starches debranched with isoamylase were analysed by size-exclusion chromatography and showed the presence of an intermediate compound with chain length between that normally found for amylose and amylopectin. Debranched amylopectin of low molecular size were present in a higher amount in the afternoon than in the morning