Localisation of Amylose and Amylopectin in Starch Granules Using Enzyme-Gold Labelling

Abstract

Waxy maize (0 % amylose), potato (21 % amylose) and amylomaize (70 % amylose) starches were obtained from Cerestar UK Ltd. 163The independent localisation of amylose and amylopectin in a range of dry and hydrated native starch granules with varying amylose content (0-70 %) has been indirectly visualised using enzyme-gold cytochemical markers. Increasing amylose content was clearly demonstrated to result in distinct changes in granule architecture. In the absence of amylose (waxy maize starch) a framework of closely packed concentric layers of amylopectin exists in the granules. Low amylose content (potato starch) results in alternating layers of densely packed amylopectin and amylose molecules. High amylose content (amylomaize Localisation of Amylose and Amylopectin in Starch Granules Using Enzyme-Gold LabellingNeil J. Atkin, Sophia L. Cheng, Rukmal M. Abeysekera and Anthony W. Robards, Heslington, York (United Kingdom) starch) granules were shown to possess an amylopectin centre surrounded by an amylose periphery encapsulated by an amylopectin surface. Elongated granules without the amylopectin centre were also observed in high amylose starches suggesting a relationship between amylopectin, amylose and granule shape. A model of starch granule architecture is proposed where increased compartmentalisation of amylose and amylopectin is observed in granules containing increasing levels of amylose.

Physicochemical and Thermal Properties of Phaseolus vulgaris L. var. Great Northern Bean Starch

“…Although negative relationships between relative crystallinity and amylose proportion have been proposed (Jenkins and Donald ; Atkin and others ) our results did not follow the same pattern; starch from cultivar Beryl‐R had a relatively low amylose content and low relative crystallinity, whereas starch from Coyne showed relatively high values in both categories (Table and ). Although most cereal (A‐type) and tuber (B‐type) starches follow the conventional theories on the origins of crystallinity and its dependence on amylose/amylopectin proportions (Cheetham and Tao ), C‐type starches, such as Great Northern bean studied here, usually do not follow the same patterns (Hoover and Ratnayake ; Jenkins and Donald ).…”

Grain Quality Characteristics and Milling Performance of Full and Partial Waxy Durum Lines

“…Grant et al (2004) also found higher fat content in durum waxy wheat. The influence of amylose on the granule architecture was demonstrated by use of enzyme gold labeling (Atkin et al 1999). In waxy starch, a framework of closely packed concentric layers of amylopectin exists in the granules and is likely to affect the behavior of the endosperm when crushed in the mill.…”

Relationship between ?-amylase degradation and the structure and physicochemical properties of legume starches

“…The independent localization of amylose and amylopectin in starch granules with varying amylose contents (0 -70%) by enzyme-gold labeling (Atkin et al, 1999) revealed that the location of amylose differed with different amylose contents. Amylose in low amylose content potato starch was mainly located in the amorphous growth rings alternating with semi-crystalline growth rings, whereas high amylose content (amylomaize) granules were shown to possess an amylopectin center surrounded by an amylose periphery encapsulated by an amylopectin surface.…”