Modification in Physicochemical, Structural and Digestive Properties of Potato Starch During Heat-Moisture Treatment Combined with Microwave Pre- and Post-Treatment

Abstract

The objective of this study was to investigate the effects of modification by heat-moisture treatment (HMT) combined with microwave pre- and post-treatment (MW) on the physicochemical, structural and digestive properties of potato starch. The light microscopy, scanning electron micros copy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) were used to determine the structural properties of starch. FT-IR and XRD spectra implied that MW and HMT destroyed the double helices and crystalline structure of potato starch. The relative crystallinity of modified starch granules (15.17–18.17%) was lower than that of native starch (19.39%). In the case of physicochemical properties, the modified starches had higher pasting temperature (68.8–93.0°C) and setback viscosity (807–3168 cP), but lower peak viscosity (1315–3662 cP) and breakdown viscosity (17.3–78.3 cP) than that of native potato starch, which were 68.5°C, 496 cP, 6598 cP and 2526 cP, respectively. The HMT and MW modifica - tions significantly increased the content of slowly digestible starch and resistant starch. The resistant starch content of starch obtained by HMT com bined with MW post-treatment was significantly higher than that of starch obtained by HMT combined with MW pre-treatment and single HMT. These results may promote good understanding of the effects of HMT combined with MW pre- and post-treatment on physicochemical properties and digest ibility of potato starch, and wide utilization of microwave and heat-moisture techniques in starch modification.