Fractionation of Fatty Acid in Palm Kernel Oil using Supercritical CO₂ at Different Pressures and Temperatures

Abstract

Application of supercritical carbon dioxide (SC-CO₂) to fractionate shorter-medium (C8-C14) and longer chain (C16-C18:2) triglycerides in terms of fatty acids constituent in palm kernel oil (PKO) was studied for formulating possible cocoa butter replacer blends. The extraction of dehulled ground PKO was carried out at 40 and 80°C and pressures ranging from 20.7 to 48.3 MPa with a flow type apparatus. The PKO was extracted successively into four fractions. At higher temperatures (80°C) the total yield of PKO increased with pressure. The highest yield (99.6%) was obtained at 48.3 MPa and 80°C with minimum CO₂ used. Much shorter chain C8, C10, C12 fatty acids constituents were extracted fraction 1. Longer chain 16, C18:0, C18:1 and C18:2 fatty acid constituents were extracted in fraction 4. The slip melting points were reduced to 6 - 8°C for fractionated PKO in the later fractions. The latter fractions had composition and slip melting points close to that of cocoa butter replacer blends.