Determination Of Deterioration And Antioxidant Activity Of Vegetagle Oils Marketed In South Eastern Nigeria

ABSTRACT

The degree of deterioration and antioxidant activity of seven edible oil from different sources as marketed in retail outlets or open market were investigated using acceptable biochemical indicators. Different brands of oils; Processed Palm oils (3 brands), olive oil, soya bean, groundnut, and cod liver oil were used for the study. Antioxidant activity was determined spectrophotometrically by measuring tile disappearance of 2,, 2-diphenyl-1- picrythydrazyl (DPPH) at 517nrn; and the degree of deterioration by iodine number and spectrophotometric determination of malonidialdehyde (a by product of lipid peroxidation. There were evidence of deterioration in all the oils as indicated by their contents of malonialdehyde and iodine numbers. Also all the oils showed varying degrees of antioxidant activity with olive oils having the highest and processed palm oil tile lowest antioxidant activity. A negative' correlation (-0.51) between tile contents of malonialdehyde and iodine number of the oils was also observed. The varying of concentration of triaclyglycerol content of the oils gave support to both the varying degree of deterioration and tile antioxidant activities of the oils.