Effect of Processing Method on Carotenoid Profiles of Oils from Three Varieties of Nigerian Palm Oil (Elaise guinensis)

Abstract

This study assessed the effect of processing method on the carotenoid profile of oil from three varieties of Nigerian oil palm fruits (Elaise guinensis). Specific varieties of the Elaise guinensis, which are the dura, pesifera and tenera were obtained from National Institute for Oil Palm Research (NIFOR) in Edo state, Nigeria. The samples were divided into two and processed using two different methods as commonly practiced in south-eastern Nigeria, the hot and cold processes. The oil extracted from each of the processes was then analyzed for oil characteristics using standard analytical methods while the carotenoid profile was analyzed using HPLC C-21 column. The results generated were subjected to the one-way analysis of variance (ANOVA). The results of carotenoid constituent identified include: lutein, neurosporene (trans), neurosporene (cis), α-Zeacarotene(cis), α-Zeacarotene(trans), phytoene, phytofluene, β-zeacarotene, 13 and 13’ cis α-carotene, 13 cis β-carotene, trans α-carotene, 9 cis α-carotene, trans β-carotene, αcarotene a(cis), α-carotene b(cis), α-carotene (trans), γ-carotene (trans), γ-carotene b(cis), lycopene (cis) and lycopene (trans). The results of physicochemical characteristics of the oil samples extracted range from 0.922 ± 0.004 - 0.916 ± 0.001 for specific gravity (SG), 8.10 ± 0.17 - 4.88 ± 0.04 mg KOH/g for acid value, 4.29% ± 0.02% - 2.44% ± 0.02% for free fatty acid value (FFA), 6.00 ± 0.21 to 204.67 ± 0.98 mgKOH/g for saponification value and 9.53 ± 0.23 - 5.25 ± 0.33 mEq/kg; for peroxide value while the carotenoids values were between 53.735 ± 0.10 and 123.389 ± 0.20 mg/100g. From the result, we can observe that the main constituent of the palm oil carotenoid is the β-carotene which makes up to about 80% of the total carotene. Statistical analysis revealed that no significant difference exists between the mean of each of the processing methods on the carotenoid profile of the oil sample analyzed.