Evaluation of Some Plant Oils Quality Commonly Sold in Ghana

Fats and oils are a class of organic compounds called lipids and are usually a mixture of triacylglycerols with their fatty acids in varying proportions. While large types of fatty acids are found in natural fats and oils, only a few of them are important to the body. Vegetable oils are an important part of an energetically balanced and healthy diet. The objective of this study was to evaluate the quality properties of three commonly consumed oils in Ghana. The chemical properties of the three oil samples, vegetable oil (Frytol), palm kernel oil, and coconut oil were analyzed to determine the peroxide value, saponification value, free fatty acid value, iodine value and moisture content. The moisture contents of the oil samples were 0.40%, 3.33% and 0.14% for vegetable oil, palm kernel oil and coconut oil respectively. Palm kernel oil recorded the highest value (11.64%) for free fatty acid and the least value of 0.17% being vegetable oil. Coconut oil recorded the least peroxide value of 0.59 mEqv·O2/kg followed by palm kernel oil (0.78 mEqv·O2/kg) and vegetable oil (0.80 mEqv·O2/kg). A high saponification value was recorded for all the oil samples with coconut oil recording the highest value of 292.12 mg/g KOH. The iodine value of the oil samples ranged from 102.59 to 237.27 mg I2/g). The high iodine values reported in this study is an indication that these oils have a high degree of unsaturation.