Ozone-Aided Corn Steeping Process

The present research evaluated the feasibility of using ozone (O ₃) to replace sulfur dioxide (SO₂) in corn steeping. Traditionally, steep water contains 0.1-0.2% sulfur dioxide to promote starch-protein separation and high starch yields, and to control microbial growth. However, residual SO₂ in starch products affects product quality and jeopardizes the "organic products" claims. Also, SO ₂ discharged to the environment pollutes water and air. Ozone is a strong oxidant and disinfectant with a capability to control the growth of putrefactive microorganisms in steeping systems, and to break down the endosperm protein matrix and, hence, improve starch release. This study demonstrates that an ozone-aided steeping (OAS) process had starch yields as high as conventional SO₂ steeping. OAS processes can be conducted at a lower temperature (20°C vs. 50°C) and for shorter times (36 hr vs. 48 hr) than the conventional SO₂ processes, suggesting significant energy savings and increased productivity. We have found that the timing of ozone application is of great importance to the performance of the OAS process.