Deodorization of coconut oil using activated charcoal and charcoal regeneration

Abstract

The deodorization of virgin coconut oil using activated charcoal was studied. Deodorization carried out at different coconut/active charcoal ratio (1:2 to 1:8 w/w charcoal:oil ratio). The effect of agitation, vacuum, and size of active charcoal (granular 2.36 mm, middle size 1 mm and powder 0.45 mm) were investigated. The sensory and gas chromatography methods were used to evaluate the deodorization efficiency. The results of deodorization have shown that active charcoal powder is the most effective for deodorization compared to granular and middle size charcoal. Within 1 day the virgin coconut oil could be deodorized after applying 1:2 w/w active charcoal powder:oil. Decreasing the charcoal to oil ratio prolong the deodorization time. The GC analysis of deodorized coconut oil have shown that nearly all composition of virgin coconut oil remain unchanged during deodorization using active charcoal. Used active charcoal containing oil was subjected to oil extraction and regeneration. Extraction of used charcoal using hexane solvent and subsequent evaporation of hexane residue in oven yielded up to 80% reactivation of used active charcoal. Further increasing the activity of used regenerated charcoal could be achieved using chemical charcoal activation by means of ZnCl 2 . Up to 100% recovery of activity could be achieved after ZnCl 2 reactivation of regenerated active charcoal. Subcritical water (at 200°C, 30 min) as physical and environmentally friendly method was suitable for regeneration of used charcoal. Nearly up to 90% recovery of activity could be achieved after subcritical water treatment.