Extraction of palm oil from palm mesocarp using sub-critical R134a

Abstract

Experiments involving extraction of palm oil from treated palm fleshy mesocarp were carried out using a dynamic method to determine palm oil yield and solubility in sub-critical 1,1,1,2-tetrafluoroethane (R134a). Effects of crucial process parameters including R134a pressure, temperature and flowrate as well as sample pre-treatment on palm oil yield and solubility were examined. R134a pressure was varied from 60 to 100 bar whereas temperature, from 40o to 80oC. The palm oil extracts were analyzed using gas chromatography (GC) analysis and ultraviolet-visible (UV-Vis) Spectrophotometer to determine the compositions of fatty acids and ß-carotene extracted. The experiments were designed using response surface methodology (RSM) to model the extraction yield of palm oil as a function of pressure and temperature. The experimental palm oil solubility data was successfully correlated using Chrastil model, density-based model and temperature-pressure (T-P) model by means of multiple regressions for prediction purposes. The coefficient of determination, R2, values for the empirical models were 93.68%, 96.38% and 93.97%, respectively. Analysis of variance (ANOVA) showed that palm oil yields and solubility were highly temperature-dependent and moderately pressure-dependent, with p-value of <0.05 at 95% significant level. Sub-critical R134a was a suitable solvent for palm oil extraction since the degree of extraction (defined as the ratio of yield by R134a to Soxhlet) was 93.34%. Substantial oil yields and solubility at much lower pressure than those required by supercritical carbon dioxide proved that sub-critical R134a is an alternative solvent for palm oil extraction even though supercritical carbon dioxide leads to higher oil yields.