Effect of refining processes on antioxidant capacity, total contents of phenolics and carotenoids in palm oils.

Antioxidant capacity (AC), total phenolic content (TPC) and total carotenoid content (TCC) in palm oils at various stages of the refining process from two technological modes were determined. The obtained mean FRAP and DPPH values for the methanolic extracts of palm oils from mode 1 (19.5-102.8μmol TE/100g and 18.8-103.0μmol TE/100g) were lower than for oils from mode 2 (25.6-134.8μmol TE/100g and 25.4-135.4μmol TE/100g). The total phenolics (4.1-12.4mg GA/100g) and carotenoids (0.18-45.8mg/100g) in the studied oils were correlated with their antioxidant capacities determined by FRAP and DPPH methods (r=0.6623-0.9878). During the refining process, for both technological modes resulted in a loss of AC by 80%, TPC by 26-55% and TCC by 99%. The bleaching step caused the highest losses of AC as determined by FRAP 41% and 46%, DPPH by 43% and 48%, while TPC loss was 45% and 23% and loss of carotenoids was 49% and 56%, in mode 1 and mode 2, respectively.