Heating-cooling extrusion cycles as a method to improve the physicochemical properties of extruded corn starch

This work proposed a controlled method to modify the physicochemical properties of corn starch through heating and cooling extrusion (HCE) cycles. It was used native corn starch adjusted to 60% moisture. It was then subjected to 5 HCE cycles at 100 and 125 °C, at 10 rpm. Water absorption index (WAI), water solubility index (WSI), resistant starch (RS), thermal properties, viscosity, FTIR, and X-ray were evaluated. For WAI and WSI, a gradual increase was observed on each HCE cycle. Thermal properties shown that enthalpy decrease with each HCE cycles due to more gelatinization. Viscosity properties shown a thermally stable starch conditions being directly proportional to HCE cycles. The RS increased for each 5 HCE. XRD revealed that HCE cycle changed the starch structure from an orthorhombic structure to V-type crystalline structure. Finally, it was concluded that HCE cycles is a method to produce corn starch with controlled physicochemical properties. •Extrusion heating-cooling cycles (EHCC) change and sharpen the crystalline structure of corn starch.•HCE cycle modifies the resistant starch (RS) percentage.•HCE cycle increases the starch's water absorption and solubility indexes.•HCE cycles decreased the gelatinization enthalpy.•HCE cycles produced a retrograded thermally stable starch.