To analyse the oil content in the emulsion and aqueous phase from combined extraction, 20 ml of petroleum ether 40/60 was added to freeze dried samples and mixed by vortex for 30 s. The samples were incubated overnight, followed by centrifugation at 3000 × g (4◦
C, 20 min). Two phases, petroleum ether contain-ing extracted oil at the top and remaining solid at the bottom, were formed and separated. Petroleum ether was removed from the collected oil using rotary evaporator. Oil content was deter-mined by weighing. Oil content of the residue was calculated by difference