Effect of microwave treatment (low power and varying time) on potato starch: Microstructure, thermo-functional, pasting and rheological properties

Abstract

The present study focused on the effect of microwave treatment (300 W for 1, 3 and 5 min) on the physicochemical, morphological, structural and rheological properties of potato starch. Significant effect (p < 0.05) of treatment time was observed on water activity and moisture content while non-significant effect occurred on color. Water absorption capacity increased from 0.82–1.16 g/g with treatment time while oil absorption capacity decreased from 0.63–0.53 g/g. Dynamic and loss moduli, pasting temperatures and final viscosities were positively correlated with treatment time. The peak and pasting viscosity incremented till 3 min treatment but decreased at 5 min. Onset temperature of gelatinization ranged from 53.8 to 57.4 °C with treatment time. SEM micrographs showed unaffected starch granules at 1 min of treatment while fissures and indentations developed at 3 and 5 min. The X-Ray diffraction patterns indicated the transformation of starch crystals from B crystallite to amorphic type.