Physicochemical Characteristics and the Effect of Packaging Materials on the Storage Stability of Selected Cucurbits Oils

Abstract

Physicochemical properties and the effect of packaging materials on the quality of oil extracted from Cucumeropsis manni, Lagenaria sicceraria and Citrullus lanatus were studied in this work. Oil was extracted from Lagenaria sicceraria (bottle gourd), Cucumeropsis manni (white melon) and Citrullus lanatus (watermelon) seeds, some physicochemical attributes of the oil extracted were determined. The three samples of oil were stored in amber glass bottle, transparent glass bottle and transparent plastic bottle at ambient temperature for 12 weeks during which stability of the oil to oxidative and hydrolytic deterioration was assessed by determining peroxide value and free fatty acid value at 2weeks interval. The results show that the physicochemical characteristics of oil samples extracted from Lagenaria sicceraria, Cucumeropsis manni and Citrullus lanatus seeds were: specific gravity 0.89, 0.90, 0.87; refractive index 1.517, 1.520, 1.518; iodine number 97.16 mgI2/g, 101.52 mgI2/g, 98.26 mgI2/g; saponification value 215.99 mgKOH/g, 221.60 mgKOH/g, 183.73 mgKOH/g; thiobabituric acid number 4.45 mgMA/Kg, 2.03 mgMA/Kg, 2.19 mgMA/Kg; free fatty acid value 18.80%, 0.57%, 5.31% and peroxide value 0.02 Meq/kg, 0.14 Meq/kg, 0.09 Meq/kg respectively. The result of storage stability shows that the oil samples may be relatively stable to oxidation and hydrolysis when properly stored in a good packaging material. Oil samples stored in plastic transparent bottle recorded highest lipid peroxidation values while amber glass bottle gave the maximum protection against lipid peroxidation.