Optimization of corn soaking conditions in wet milling through the application of protease enzymes

Conventional wet milling of corn relies on extended steeping with sulfur dioxide, which is energy intensive and generates solute losses as well as environmental concerns. This study explored the potential of enzyme-assisted soaking as an alternative approach to improve efficiency and product quality. Yellow corn was subjected to traditional steeping (48 h with 2000 ppm sulfur dioxide) and to treatments with the protease ProEx FG at varying concentrations (1–4 mL/100 g) for shorter durations (2–8 h). Key parameters evaluated included starch yield and purity, fiber content, germ and oil recovery, protein composition, and soluble solids. Traditional soaking produced 68% starch with 98.1% purity and 6.4% soluble losses. In contrast, enzyme-assisted soaking shortened processing time, increased starch purity to 99.4%, and reduced soluble losses to 0.72%. Higher enzyme concentrations enhanced protein solubilization but could lower starch and oil recovery due to excessive degradation or limited hydration. The most effective treatment was 2 mL enzyme/100 g corn for 8 h, which balanced starch purity and oil recovery. Overall, enzyme-assisted soaking provides a promising alternative to conventional corn steeping by reducing time and solute losses while improving product quality, with process optimization being crucial for industrial application.