Fractionation, characterisation and optimisation of refined, bleached and deodorised palm oil using progressive freeze concentration

Abstract

The aims of this experimental work were to study the influence of operating condition on progressive freeze concentration (PFC) of refined, bleached and deodorised palm oil (RBDPO) using coil crystalliser and to determine the optimum condition based on the response of effective partition constant (K) and triglyceride (TG) of olein. The operating condition of circulation flowrate (CF, 2000 to 3000 mL/min), coolant temperature (CTemp, 24 to 29 ºC), circulation time (CTime, 40 to 60 minutes), and initial iodine value (IIV, 50 to 55 wijs) could affect the efficiency of RBDPO fractionation process where mass and heat transfer study and economic analyses were carried out. The results indicated that CF of 2800 mL/min, CTemp of 28 °C, CTime of 60 minutes, and IIV of 55 wijs gave high value of iodine value (IV) and low value of slip melting point (SMP) for olein in the range of 56.97 to 55.84 wijs and 21.57 to 23.04 °C, respectively. The optimization process found that the operating parameter of CF, CTemp and CTime were not significant as indicated by the p value of less than 0.05 from the Pareto chart, meanwhile IIV was significant. Furthermore, the optimum condition for low K and high olein‟s TG found using software assisted response surface methodology (RSM) were in the following range: 2502 to 2537 mL/min for CF, 26 to 27 °C for CTemp, 53 to 54 minutes for CTime, and 56.8 to 56.9 wijs for IIV. For energy and cost analysis, it was found that the fractionation of RBDPO through PFC is cheaper than the conventional fractionation as it has been calculated that the energy usage and production cost for PFC are 0.025465 kW/hr/kg and RM0.03/kg of RBDPO respectively. All the analyses supported the objectives of this study and gave enough evidence of good performance and quality of olein as well as low cost of operation in PFC fractionation.