Physicochemical, structural, digestive properties, and interaction mechanism of Tartary buckwheat starch-Rutin-calcium hydroxide complex

Int J Biol Macromol. 2024 Nov 5;282(Pt 5):137269. doi: 10.1016/j.ijbiomac.2024.137269. Online ahead of print.

Abstract

Tartary buckwheat is rich in starch and rutin, with Ca(OH)2 often used to improve the quality of buckwheat-extruded noodles. This study investigated the properties of a system combining tartary buckwheat starch (TBS), fixed Ca(OH)2 (0.6 %), and varying rutin addition (R, 2-10 %) to understand their interactions. Rutin addition in the presence of Ca(OH)2 significantly affected the structural and physicochemical properties of TBS in a dose-dependent manner. Microscopy showed that rutin particles precipitated on the gel walls of the TBS-R-Ca complexes at high rutin doses, more noticeably without Ca(OH)2. Rutin decreased gelatinization viscosity, whereas Ca(OH)2 alleviated this reduction in viscosity and gel structure. Ca(OH)2 and 2 % rutin significantly reduced the gelatinization and retrogradation enthalpies, relative crystallinity, short-range order degree, and TBS digestion rate. 1H NMR spectroscopy revealed interaction sites between rutin and TBS. Molecular dynamics results indicated that rutin and TBS can form effective hydrogen bonds and hydrophobic interactions, with Ca(OH)2 helping to maintain system stability.

Keywords: Ca(OH)(2); Interaction mechanism; Rutin; Structural and digestive properties; Tartary buckwheat starch.