Chemical Changes in Crude Palm-Oil and Refined Palm Kernel-Oil Employed in Deep-Frying

Abstract Crude palm oil and refined palm kernel oil samples were used in the frying of plantain and were compared to same oil samples ordinarily heated without frying, these served as control. The chemical analyses covered free fatty acid, peroxide, anisidine, iodine and saponification values. These values measure the extent of the oil degradation, i.e oxidation, hydrolysis, splitting and polymerization. From the results, there is no noticeable change between the free fatty acid values of oil samples used for frying and the oil samples used as control. The much higher values of peroxide formation in refined palm kernel oil used as control compared to crude palm oil used as control may be due to the presence of some natural antioxidants in crude palm oil used as control. It is plausible to suggest that the higher rise in the anisidine values of oil samples used as control compared to those of oil samples used for frying is due to the absorption, by the fried plantain, of parts of the products of secondary oxidation formed in the oil samples used for frying. The data obtained for the iodine value of all the oil samples fall within the acceptable range for the respective oils. The saponification value of refined palm kernel oil sample used for frying decreases while that of refined palm kernel oil used as control decreases at the first instance then increases steadily. The data collected show the suitability of these two oil samples for frying purposes and indicate that, in terms of chemical composition, refined palm kernel oil (RPKO) performs more satisfactorily as frying oil, because it has higher oxidative stability than crude palm oil (CPO).

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Updated: May 6, 2017 — 10:21 am
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