Mechanistic insights into the role of hydrocolloids in modulating the rheological properties and flow behavior of alkaline-treated cassava starch

Abstract

This study investigated the effects of blending alkaline-treated cassava starch (ATS) with hydrocolloids-guar gum (GG), carrageenan (C), locust bean gum (LBG), konjac powder (KP), and sodium alginate (SA)-on the physicochemical, pasting, thermal, and structural properties of cassava starch (CS). Alkaline treatment disrupted starch crystallinity, increasing its susceptibility to modification. Hydrocolloid incorporation enhanced the peak viscosity, holding capacity, and final viscosity of ATS, while reducing setback viscosity, indicating improved resistance to retrogradation. ATS + SA and ATS + KP exhibited the highest stabilization effects, as reflected in their increased viscosities and reduced amylopectin reassociation. Differential scanning calorimetry (DSC) revealed increased gelatinization temperatures and reduced enthalpy values in the composites, suggesting enhanced thermal stability. Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) confirmed hydrocolloid-induced structural modifications via hydrogen bonding. Scanning electron microscopy (SEM) and low-field nuclear magnetic resonance (LF-NMR) analyses demonstrated the formation of a hydrated matrix that improved water retention and minimized syneresis. These findings highlight the potential of ATS-hydrocolloid composites for enhancing the stability, texture, and shelf life of starch-based systems, providing insights for optimizing hydrocolloid use in starch modification and functional food applications.

Keywords: Alkaline treatment; Cassava starch; Gelatinization; Hydrocolloids; Retrogradation; Stabilization; Structural modification.