amylosetoamylopectin

Amylosetoamylopectin is a term used in starch chemistry to describe a class of glucan macromolecules in which amylose and amylopectin components are covalently linked within a single polymer chain, rather than existing as two separate polysaccharides within a mixture. The concept contrasts with native starch, where amylose and amylopectin are present as distinct but coexisting fractions within granules.

The structure of amylosetoamylopectin can vary, but typical features include segments of mostly alpha-1,4-linked glucose chains resembling amylose interconnected with branched regions that resemble amylopectin. This results in a single molecule that contains both linear and branched motifs. The precise pattern of linkage and chain length influences crystallinity, gelatinization behavior, and digestibility.

Formation of amylosetoamylopectin-like polymers can occur during enzymatic modification or chemical cross-linking of starch, or through specialized biosynthetic processes under certain conditions. In some studies, isolations of amylose-rich fractions bearing covalently attached amylopectin residues have been described, but the term is not universally standardized and is often discussed in the broader context of amylose–amylopectin hybrids or covalently linked starch derivatives.

Properties and applications of these hybrids may include altered gelatinization temperatures, viscosity profiles, and retrogradation tendencies, as well as modified digestibility. Such characteristics are of interest in food science for texture and glycemic response, and in materials science for potential use in biodegradable matrices or controlled-release systems.

See also: amylose, amylopectin, starch, modified starch, glucans, cross-linking.