Concentration of minor components in crude palm oil

This study deals with the enrichment of minor constituents from crude palm oil with supercritical CO2. Direct extraction of carotene using CO2 is not very practical, so the main component of crude palm oil, triglyceride, has to be transesterified. Fatty acid ester has a solubility magnitudes higher than triglyceride in CO2. The beginning material is crude palm oil, which has a concentration of free fatty acid up to 4%, 600 ppm tocochromanols and 500 ppm carotene. The free fatty acid was first separated, and the crude palm oil was then transesterified to fatty ester methyl esters (FAME) with methanol using base catalyst. Afterwards, the glycerol was separated and the product was washed with water to remove catalyst and methanol. In a pilot counter-current extraction apparatus, which was built according to the mixer-settler principle, fatty acid methyl esters were extracted at 60 °C and 140 bar. The apparatus was operated with a CO2 flow rate of 20 kg/h. With three steps of extraction, an enrichment of 200-fold for carotenoids and 100-fold for tocochromanols was found. Theoretical description of the extraction experiments are also discussed. The five-stage mixer-settler apparatus achieved approximately four theoretical separation stages. It is demonstrated that SFE can be an alternative method to recover minor constituents in crude palm oil.