The Effect of Soaking on the Biochemical and Nutritional Properties of Corn and Millet Flours

Abstract

This study aims to evaluate the effect of soaking three types of flour, based on white and yellow hybrid corn 'Zea mays (L.)' and millet 'Pennisetum glaucum (L.)', on physicochemical parameters. The soaking times were 0; 6; 12; 24; 48; 72, and 168 hours for the corn varieties, and 0 and 6 hours for the millet. Two corn flours from grains soaked for 168 hours were produced, one of which was marked by the addition of potash. In total, 18 flours were produced. The analyzed physicochemical parameters showed a significant decrease, particularly after 168 hours of soaking. The minimum and maximum values were observed in the pH of white flour (4.73%) and the ash content of yellow flour (75%), respectively. Similarly, the protein, lipid, and carbohydrate contents decreased significantly. A significant decrease in carbohydrate content of yellow flour (77.28%) is observed. Adding potash further reduces protein, lipid, and carbohydrate levels. In white flour, significant decreases in content were observed for magnesium (91.10%), manganese (64.32%), and zinc (81.32%) without the addition of potash. However, a significant increase in iron (146.13%) and calcium (78.39%) content is observed in yellow flour. Similarly, increases in pH and ash content are observed in potash flours. A significant increase was observed in the potassium content of white flour (120%). For millet flour, reductions were predominantly observed in the carbohydrate (12.03%), potassium (32.72%), and fiber (33.61%) contents. The nutritional profile of flours varies depending on the technique used, with soaking having an impact on their biochemical composition.