The independent localisation of amylose and amylopectin in a range of dry a
nd hydrated native starch granules with varying amylose content (0-70 %) ha
s been indirectly visualised using enzyme-gold cytochemical markers. Increa
sing amylose content was clearly demonstrated to result in distinct changes
in granule architecture. In the absence of amylose (waxy maize starch) a f
ramework of closely packed concentric layers of amylopectin exists in the g
ranules. Low amylose content (potato starch) results in alternating layers
of densely packed amylopectin and amylose molecules. High amylose content (
amylomaize starch) granules were shown to possess an amylopectin centre sur
rounded by an amylose periphery encapsulated by an amylopectin surface. Elo
ngated granules without the amylopectin centre were also observed in high a
mylose starches suggesting a relationship between amylopectin, amylose and
granule shape. A model of starch granule architecture is proposed where inc
reased compartmentalisation of amylose and amylopectin is observed in granu
les containing increasing levels of amylose.