IMPROVING THE QUALITY OF USED FRYING OILS BY TREATMENT WITH ACTIVATED CARBON AND SILICA.

This study was undertaken to investigate the effectiveness of activated carbon and silica in removing the degradation products present in used frying oils. Two batches of canola oil were treated with mixtures of activated carbon and silica. Three levels of activated carbon (3%, 6%, 9%, wt/wt) were blended with three levels of a silica compound (2%, 4%, 6%, wt/wt) in all nine possible combinations. Oil 1 was prepared by continuous heating in the lab, and oil 2 was obtained from a small potato-frying operation. For each treatment combination of silica and carbon, the average percent decrease for acid value, peroxide value, photometric color, polar compounds, saturated carbonyls and unsaturated carbonyls were obtained.