PHYSICOCHEMICAL ANALYSIS, PHYTOCHEMICAL SCREENING AND ANTIMICROBIAL ACTIVITIES OF SOME VEGETABLE OILS FROM OGUN STATE, NIGERIA

The study was carried out to assess the physicochemical properties, phytochemical screening and antimicrobial activities of twenty five different edible vegetable oil samples collected from Ota, Ogun state in Nigeria for their domestic and commercial applications. The moisture contents (0.02 – 0.13%), acid values (0.46 – 1.73 mg KOH/g), saponification values (226.19 – 310.19 mg KOH/g), iodine values (0.06 – 1.17 mg I2/g) and the low pH values (0.0 – 2.49) generally make these vegetable oils to be more useful in industrial applications than consumed directly or indirectly as ingredients in food. The results of the phytochemical screening of these oil samples indicated the presence of terpenoids, deoxysugar, steroids and cardenolides. The microbial sensitivity tests showed that most of the vegetable oil samples exhibited no inhibitory power against candida, Klebsiella pneumonia, Escherichia coli but only sample 25 (soya bean oil) was sensitive to these three microbes and its inhibition of these microbes was concentration dependent. The mineral contents of these oils showed detectable levels of Zn (2.57 –21.43 ppm), Mn (0.12 – 0.98 ppm), Fe (2.21 – 97.41 ppm), Cu (0.49 – 61.70 ppm), Cd (0.42 – 0.74 ppm) and Pb (0.14 – 31.09 ppm) which were found to be above the WHO permissible limits for these metals in drinking water