Nixtamalization application as a quality improvement of corn flour

The corn is very potential to be processed as a flour and a starch material in food industry as a food ingredients and other industries. However, the functional properties of corn flour are less favored to be applied in processed products because of its unpleasant texture and short shelf life due to its fat content. One way to improve its quality is by nixtamalization process, it is a process of boiling the corn grains in lime water followed by soaking for several hours, then washing and milling to forming a dough. The purpose of this study was to evaluate the effect of nixtamalization on corn flour physicochemical properties and rheology. The experiments were prepared by a single treatment, with variation nixtamalization/ immersion duration in lime solution (control, 8, 16, 24, and 32 hours). This treatment was repeated 3 times. The results indicated that the nixtamalization time had an effect on the corn flour proximate value and rheology, the protein content increased (3.1766% - 4.4055%) and the moisture content increased (6.9986% - 8.3217%), however the fat content decreased (4.5179% - 3.2317%) and ash content decreased (1.6674% - 1.3558%) as an increasing nixtamalization time. In general, the corn flour paste characteristics are gelatinization were changed as the nixtamalization time increased, the initial temperature decreased (84.4 °C - 80°C), the maximum viscosity decreased (136 BU - 123 BU), and the paste stability decreased (14 BU – 6 BU), but its reverse viscosity increased (69 BU – 120 BU). The different nixtamalization period had no effect on the formation of corn starch gel. The corn flour dough expansion volume increased as the nixtamalization time increased, and the structure of corn starch granules is changed/damaged as the nixtamalization time increased.