Supramolecular structure of Artocarpus heterophyllus Lam seed starch prepared by improved extrusion cooking technology and its relationship with in vitro digestibility

Abstract

Jackfruit seed starch (JFSS) was modified by an improved extrusion cooking technology (IECT), and the supramolecular structure, molecular weight, debranched chain length distributions, relative crystallinity (Rc), and amylose content, were studied. During IECT, the α-1.4-glycosidic bond in amylopectin was broken, which led to decreased radius of gyration (Rg), number-average molar mass (Mn), weight-average molar mass (Mw), long chains and Rc. The medium and short chains and PI (Mw/Mn) increased, while the amylose content hardly changed. The crystalline structure of JFSS was converted from A-type to V-type. Increasing the temperature and screw speed during the treatment significantly increased the medium and short chains and Rg, while it decreased the long chains, amylose, Mn, Mw, PI, and Rc. However, the opposite effect was observed when increasing the moisture content. The in vitro digestibility of JFSS was significantly improved after IECT, due to destruction of starch supramolecular structure according to principal component analysis.

Keywords: Improved extrusion cooking technology; Jackfruit seed starch; Principal component analysis; Starch digestibility; Supramolecular structure.