Efficient production and multiscale characterization of amorphous granular potato starch by microwave-assisted ethanol treatment.

Amorphous granular starch (AGS), characterized by loss of crystalline order while retaining granular morphology, exhibits altered hydration and digestibility compared to native starch; however, conventional production methods often rely on strong alkaline reagents. This study developed a green and rapid approach to prepare AGS from potato starch using microwave-assisted ethanol treatment (55-70% v/v). X-ray diffraction confirmed a pronounced loss of crystalline order, with relative crystallinity decreasing from 21.81% to 3.20%. Scanning electron microscopy revealed ethanol-dependent morphology, with deformation and agglomeration at lower ethanol concentrations and higher integrity at elevated levels. Rheological properties showed reduced shear-thinning behavior and increased viscosity, indicating a shift toward Newtonian flow. Rapid visco analyzer profiles demonstrated disappearance of typical pasting behavior. In vitro digestion indicated that rapidly digestible starch increased from 6.12% to 26.19%, accompanied by accelerated hydrolysis kinetics. Overall, microwave-ethanol treatment provides a clean-label and efficient approach for producing AGS with tunable properties.