Optimizing Bleaching Process Parameters of Distillers Corn Oil for edible applications using a response surface methodology

The bleaching process is aimed at removing pigments, traces of metals, and residual phospholipids to improve the color, stability, and quality of the oil. Distillers corn oil (DCO) contains lots of β-carotene that are beneficial but no study has focused on optimizing the removal of pigments while minimizing the loss of β-carotene. Hence, a response surface methodology with the Box-Behnken design was used to study the effect of the process parameters during bleaching. The process parameters were dosage of bleaching clay (1 − 3%), time (5 − 25 min), and temperature (90 − 110 °C) for neutralized DCO on the laboratory scale. The optimal parameters were bleaching clay dosage of 1.2%, time of 23.2 min, and temperature of 99.1 °C. The β-carotene reduced from 0.2% to 36%, red color reduced from 27% to 88%, and yellow color reduced from 0% to 83%. The PV values of the bleached oil sample ranged from 1.7 to 9.4 meq O₂/kg. The quality of DCO at the optimal bleaching level was compared with conventional edible corn oil. The models developed was used to identify the precise balance between enhancing color removal and maintaining beneficial nutritional values.