Starch gelatinization, retrogradation, and enzyme susceptibility of retrograded starch: Effect of amylopectin internal molecular structure.

Amylopectin internal part refers to the part between the reducing end and the outmost branches. The importance of amylopectin internal structure affecting starch gelatinization and retrogradation as well as enzyme susceptibility of retrograded starch was explored. A total of 13 different starches from a range of plants were used. Great variations in the structure and properties of these starches were obtained. Longer lengths of internal chain segments (e.g., total internal chain length) and more long internal chains (e.g., B3-chains) of amylopectins were related to more ordered physical structure in native and retrograded starches. More clustered A-chains contributed to more ordered physical structure in the starches. The more ordered structure was reflected by a higher thermal stability and melting enthalpy changes of the starches. It was also related to a higher resistance to enzyme hydrolysis of the retrograded starches.