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<sup>–3</sup>, a viscosity of 26.4 mPa·s<sup>–1</sup>, an acid value of 46.4 mg KOH·g<sup>–1</sup>, an iodine value of 98.0 g iodine·100 g<sup>–1</sup>, trace water and sediment contents, and zero ash content. The resin had a viscosity of 4 694.8 mPa·s<sup>–1</sup>, a total phenolic content of a 4.51% gallic acid equivalent, an antioxidant activity of an 8.82 mg ascorbic acid equivalent·g<sup>–1</sup>, and an acid value of 126.2 mg KOH·g<sup>–1</sup>.