Combined molecular and supramolecular structural insights into pasting behaviors of starches isolated from native and germinated waxy brown rice

Abstract

In order to provide a theoretical basis on how germination treatment modulated the pasting behaviors of starches from native and germinated waxy brown rice, impacts of germination on the molecular and supramolecular structures and pasting behaviors were evaluated. Multiple analytical methods such as thermodynamics and spectroscopy were applied in this work for investigating the changes in starch multiscale structure and pasting behaviors. The results show that germination treatment contributed to an obvious increase in α- and β-amylase activities, which could degrade the starch chains and reduce the contents of double helices (50.9%–43.2%), short-range ordered degree (1.054–0.908), relative crystallinity (40.1%–30.5%), and lamellar ordering degree (dc, 6.09–5.46 nm) along with apparent erosion on starch granules. These structural amorphizations at the molecular and supramolecular levels could lead to the weakened entanglements and interactions among molecular chains, eventually reducing the characteristic viscosity (e.g., overall, peak, and final viscosity) of starch. This study may facilitate better development of germinated rice-based products.