Effect of grinding methods on quality characteristics of corn flour

In the process of grinding, the corn grain structure was broken and ground into powder under the action of shear force and friction force. shear force, friction force, and thermal effect caused by mechanical action of corn grain are different, which leads to different quality characteristics of the finally prepared corn flour, but there are few studies reports on the influence of grinding methods on the quality characteristics of corn flour. To investigate the impact of grinding methods on the quality characteristics of corn flour, three distinct grinding methods-hammer mill, ultrafine grinder, and disc mill-were employed to mill degermed corn grits. Notably, the disc mill was operated at three different rotor speeds (1 500, 3 000, and 4 500 r/min) to study the effects of various quality indicators of the resulting corn flours, including physicochemical properties, color, particle size distribution, gelatinization characteristics, thermodynamic properties, and microstructure. The results indicated that: corn flour prepared using the hammer mill exhibited the least moisture loss, the largest average particle size, and the yellowest color; corn flour produced by the ultrafine grinder had small particle sizes but high damaged starch content, the highest water absorption index, and the lowest gelatinization temperature and gelatinization enthalpy; corn flour made with the disc mill showed the lowest damaged starch content and setback value, as well as the highest oil-holding capacity, peak viscosity, trough viscosity, and gelatinization enthalpy. When comparing the corn flours prepared by the three grinding methods, those from the disc mill were found to have small particle sizes and low damaged starch content, making them suitable for use in steamed food products.