Optimisation of concurrent Calophyllum oil-resin extraction and separation

Abstract

This research optimised the application of a hexane-methanol mixture as a binary solvent for the concurrent oil-resin extraction and separation from Calophyllum seeds on a pilot scale, in a direct stage. The optimum oil and resin yields were determined by optimising the extraction conditions using response surface methodology and a second order polynomial model. The extraction conditions affected the oil and resin yields, with the extraction time as the biggest influencing factor. Optimum oil (65%) and resin (16%) yields were predicted to be obtained at 5.2 h and 433 rpm. The model validation with these extraction conditions showed that the predicted results and actual oil (62%) and resin (15%) yields were in passable agreement. The oil was composed of 75.4% triglycerides with a density of 0.874 g.cm-3, a viscosity of 26.4 mPa.s-1, an acid value of 46.4 mg KOH.g-1, an iodine value of 98.0 g iodine.100 g-1, trace water and sediment contents, and zero ash content. The resin had a viscosity of 4 694.8 mPa.s-1, a total phenolic content of a 4.51% gallic acid equivalent, an antioxidant activity of an 8.82 mg ascorbic acid equivalent.g-1, and an acid value of 126.2 mg KOH.g-1.

Keywords

• binary
• n-hexane
• methanol
• phenolic
• antioxidant