Comparison of quinoa and highland barley derived dietary fibers influence on the physicochemical properties and digestion of rice starch

This study investigated the potential of highland barley and quinoa dietary fibers, rich in β-glucan and pectin respectively, as cost-effective and nutritionally valuable physical modifiers for rice starch (RS). HPAEC revealed differences between the monosaccharide composition of soluble and insoluble dietary fibers sourced from highland barley and quinoa (HSDF, HIDF, QSDF and QIDF). Results from both RVA and DSC analysis revealed that the addition of low amounts of dietary fiber significantly modified the pasting properties of RS. Notably, the addition of quinoa soluble dietary fiber (QSDF) significantly inhibits the formation of a stable gel network in rice starch, even at low concentrations (0.1 %), as confirmed by rheological measurements. Furthermore, the incorporation of QSDF effectively reduces the content of rapidly digestible starch in rice starch by 15.6 % and increases the content of slowly digestible starch, from 23.36 % ± 3.02 % to 31.07 % ± 3.98 %. By leveraging the compositional richness of these fibers, this research opens up novel opportunities for developing functional food products with improved nutritional profiles, as well as for improving texture and reducing glycemic index (GI) in starch-based foods.