Optimization of palm kernel oil extraction using the SC-CO₂ technique from palm oil mill by-products in Thailand

This study investigates the variables influencing the quality of supercritical carbon dioxide (SC-CO2) extraction and the lipid composition in virgin palm kernel oil sourced from Thailand. Palm kernel oil was extracted using the SC-CO2 technique at temperatures ranging within 35–100 °C and pressures of 74–300 bar for durations of 30–90 min. At a temperature of 35 °C, a pressure of 300 bar, and an extraction time of 60 min, the carbon dioxide density was 929.64 kg/m³, and the solvent to feed ratio was 10.68 kg CO₂/kg dry weight of sample. These conditions resulted in the highest palm kernel oil yield of 42.13 ± 0.15%. The peroxide value was 0.71 ± 0.02 meq O2/kg oil, which is below that achieved with compression extraction, namely 0.83 ± 0.03 meq O2/kg oil. Additionally, SC-CO2 extraction is an efficient and selective extraction method, yielding more lauric acid (C12:0) than hexane solvent extraction or compression, with the lauric acid content reaching up to 50.10%. These findings provide valuable insights into the potential applications and nutritional properties of palm kernel oil in various industries, including food and cosmetics.