OPTIMIZATION OF OIL YIELD AND PHYSICOCHEMICAL PROPERTIES OF AFRICAN ALMOND (Terminallia catappa L.) NUT OIL USING THE RESPONSE SURFACE METHODOLOGY

The stock of African almond (Terminallia catappa L.) nut cultivated at Umudike Abia State, Nigeria was cracked and the seeds removed, and reduced to different particle sizes according to the central composite design (CCD) of the response surface methodology (RSM). Oil from the samples was extracted using the Soxhlet extraction method and ethyl ether as solvent. Yield and physicochemical properties of the oil samples were analyzed using the AOAC methods, the experimental design by and the data obtained from the experiment was analyzed using the Design Expert Version 8.0. Stalactitical analysis of experimental data showed that extraction time, temperature and particle size were significant (p<0.05) on oil yield, pH, saponification value, peroxide value, free fatty acid and iodine value. Variability between oils from the samples arose from terms of the process variables, variations from earlier works was attributed to interspecies, method of experiment, reagents and geography of the plant materials. Optimization analysis of experimental data showed that extraction time of 6 hours, extraction temperature of 54.61ºC, and particle size of 355.00 µm produced oil yield 28.17%, pH value, saponification value, peroxide value, free fatty acid value, iodine value and of 6.29, 151.08 mgKOH/g, 1.41 meq/kg, 35.82 g/100 g and 2.74 mgKOH/g of the samples respectively. Further work should be done on the oil to ascertain safety and nutritional potential.