Physicochemical and Rapid Visco Analyzer Profiling of Oxidized Maize Starch

Abstract

The impact of an oxidation process was examined relative to the physicochemical, functional, and structural characteristics of maize starch. Raw maize starch (RMS) was extracted via wet milling, while oxidized maize starch (OMS) was produced through controlled oxidation. Gelation behavior, pasting characteristics using Rapid Visco Analyzer (RVA), water and oil absorption capacities, structural change analyses, and swelling power were examined. The oxidation process significantly increased the water and oil absorption capacities of (1.5±0.01 g/g and 1.2±0.02 g/g) in OMS compared with RMS (0.9±0.01 g/g and 0.6±0.01 g/g) respectively, signifying increased hydrophilicity and exposure of non-polar sites. RVA results exhibited reductions in trough, peak, final, and setback viscosities, suggesting decreased retrogradation tendency and enhanced paste stability under heat and wear. OMS showed improved swelling power across all temperatures (55 to 95 °C), indicating increased hydroxyl accessibility and disruption of crystalline regions. Fourier transform infra-red spectra exhibited shifts in carbonyl and hydroxyl functional groups, while scanning electron microscopy showed granule alteration and surface roughening. Overall, the oxidation process enhanced thermal, hydration, and structural properties of maize starch, signifying its potential for industrial applications requiring better solubility, reduced retrogradation, and improved paste stability.