Optimization of The Bleaching Process of Sunflower Oil

Abstract

Bleaching is a crucial step in oil refining that removes unwanted pigments and oxidative products, which degrade oil quality. This study evaluated the effects of temperature (75–115 °C), adsorbent concentration (1–3 wt%), and time (20–40 minutes) on sunflower oil bleaching using a Box-Behnken factorial design in Minitab 21. Responses were divided into two groups: (I) peroxide value and spectroradiometric-based chroma and hue-angle, and (II) peroxide value and spectrophotometric-based bleaching efficiency. Under optimal conditions (approximately 78 °C, 2.95 wt% adsorbent, and 20 minutes), peroxide value decreased from 1.8 meq/kg to 0.398 meq/kg, chroma reduced from 45.89 to 9.61, hue-angle increased from 92.69 to 105.55, and bleaching efficiency reached 71.86%. Composite desirability was higher in the first group (0.97 vs 0.89), primarily due to the more objective nature of spectroradiometric parameters (hue-angle and chroma).

Keywords: Oil bleaching, Optimisation, Response Surface Method, Sunflower oil