Grinding of maize: The effects of fine grinding on compositional, functional and physicochemical properties of maize flour

The particle size of maize flour has a significant effect on its functional and physicochemical properties. In this study, maize grits were ground for various time intervals (3.5, 4, 5, 6, 10 and 14 min), and grinding effects on compositional, functional and physicochemical properties of maize flour were evaluated by using rapid visco analyzer (RVA), differential scanning calorimeter (DSC), sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and other chemical methods. The results showed that grinding could effectively pulverize the flour particles. As particle size decreases, the damaged starch and amylose content, gelatinization degree, hydration capacity, water solubility index and water absorption index were significantly (P < 0.05) increased. Grinding caused reduction in trough viscosity, final viscosity and peak time and an increase in peak viscosity and breakdown of maize flours. The starch isolated from different time treated maize flour exhibited a decrease in transition gelatinization temperature (To, Tp and Tc) and gelatinization enthalpy, whereas grinding treatments have no effects on protein content and protein primary structure of maize flour. Grinding treatment changes in the damaged granules and particle size distribution are responsible for the different maize flour properties.