Molecular structure in relation to swelling, gelatinization, and rheological properties of lotus seed starch

Abstract

Relationships between molecular structure and physicochemical properties of starch remain to be better defined. This research was a follow-up of previous studies aiming to fill this gap using lotus seed starch (LS) (a novel C-type starch source) as a model system. By means of correlation analysis, the effects of molecular structure on physicochemical properties of LS were revealed. Content and chain length of amylose affected mainly rheological properties of LS. Short and long B-chains differently affected the short-range ordered structure of starch granules, thermal properties, and the transmittance of starch paste. In addition to the influences of amylose and amylopectin internal structure, several “novel” relationships related to the effects of amylopectin external structure were found in the LS-based model system. For instance, the molar amount of clustered A-chains (Aclustered) in lotus seed amylopectin was significantly related to the short-range molecular order in the granules. Moreover, the importance of Aclustered-chains was reflected by their influences on various properties of LS upon gelatinization and retrogradation. Successive influences of the molar amount of Aclustered-chains on starch properties during pasting were revealed. This study highlighted the importance of amylopectin external structure in addition to the under-studied amylopectin internal structure in affecting starch physicochemical properties.