Microwave irradiation of corn kernels: Effects on structural, thermal, functional and rheological properties of corn flour

The current study investigated the impact of microwave treatment on the physicochemical properties of corn kernels. Three microwave powers (2, 3, 4 W/g) and three treatment times (2, 3, 4 min) were used to treat the corn kernels. The findings indicate that heat treatment increased gelatinization temperature and gelatinization enthalpy. Moreover, relative crystallinity was reduced by 17.89% in the microwave-treated flour in comparison to untreated samples, and alterations were observed in the protein secondary structure, ordered structure, and functional properties of corn flour. Microwave treatment caused the darkening of the sample and a larger particle size distribution. Higher radiation times and microwave powers exhibited more intensive treatment outcomes. Rheological tests indicated that the elastic and viscous moduli of the microwave treated corn gels were higher than those of the control group, and their large-amplitude oscillatory shear curves exhibited a strain-weak strain overshoot (type III). The results of this study suggest that microwave treatment can potentially be utilized as a technique to regulate the technical functional properties and viscoelasticity of corn flour.