ABSTRACT

A Central Composite Design (CCD) consisting three factors (solvent composition, temperature and lime of extraction) at five levels was used to study the solvent extraction of Neem oil from its seed using n-hexane and ethanol. Neem oil yield, pH, refractive index, acid value, iodine value and saponification value were evaluated as the responses. Forty-two experimental runs resulted from the CCD with a minimum oil yield of 12% and maximum of 41%. Responses surface methodology was used to analyze the results of the CCD of the extraction processes. The optimum values for yield, pH, refractive index, acid value, iodine value and saponification value from the surface plot were 43.48%, 4.99,156, 1.411glg, 89.35glg and
176.64mglg predicted percentage yield was 43.48% at solvent composition of
80.77% n-hexane, 34.930c and 6 hours duration of extraction. The five validation experiments had optimum oil yield ranged between 32.85% and 37.20% while their accompanying quality characteristics were not significantly different from the simulated values at p < 0.05.

Keywords: Neem oil, response surface methodology, central composite design, oil yield