Research Article
K. K. Adama and M. O. Edoga
Abstract
This work compared the extraction of oil from the pericarp (peels) of avocado apples using two different solvents namely n–hexane and anhydrous ethanol. Direct and indirect leaching methods were used to extract the oil from the pericarp of the apples. The extraction was carried out at different particle sizes, times, and boiling points of the solvents. These were as follows: 0.75mm,1.00mm, 1.59mm and 2.00mm; 30, 60, 90 and 120 minutes; 600C and 780C for n–hexane and anhydrous ethanol respectively. The oil extract (active principle) was further refined. The crude and refined oils were characterized to define their physicochemical properties and hence their suitability for industrial applications. Comparative analysis of the results at optimal thermodynamic conditions of reaction time (120minutes), particle size (0.75mm), boiling point of solvents used (n–hexane, 600C and anhydrous ethanol, 780C) revealed an optimum oil yield of 21.2% and 23.9% for indirect and direct extraction using n–hexane, 35.9% and 42.0% for indirect and direct extraction using anhydrous ethanol respectively. Physicochemical analysis of the refined oil showed a saponification value of 196.4, iodine value of 5.653, free fatty acid value of 0.0872, specific gravity of 0.90261, refractive index of 1,600, viscosity of 181.180cp, and boiling point of 890C. Based on the conformity of these properties to the international standard (ISO/TR 21092, ISO/TR 210,ISO 212, AOCS), the present oil is a potential substitute for most oils used for cosmetics and health care production.