Life cycle assessment of refined sunflower oil production for food industry: Exploring hexane-free alternative using supercritical CO2 for processing pressed cake

Sunflower oil, valued for its high polyunsaturated fatty acid content and antioxidant properties, is primarily extracted using a two-stage process involving mechanical pre-pressing and hexane extraction. Despite its efficiency, hexane extraction raises significant environmental and health concerns. Supercritical carbon dioxide offers a green alternative with advantages in safety and regulatory compliance. This study conducts a comparative Life Cycle Assessment (LCA) of conventional hexane extraction versus Supercritical Fluid Extraction using carbon dioxide (SFE-CO2), where in the case of SFE-CO2 two methods for regeneration of CO2 after the extraction step are considered: conventional decompression and a novel membrane separation technique. The LCA, performed using the ReCiPe 2016 methodology and SimaPro software, evaluates environmental impacts across 18 midpoint and 3 endpoint categories. The results show that SFE-CO2 with decompression recovery has higher environmental impacts than hexane extraction (due to higher energy consumption) but the use of membrane filtration for CO2 regeneration significantly reduces these impacts. Compared to hexane extraction, SFE-CO2 with regeneration by membrane achieves a 95 % reduction in environmental impact and a 99.3 % reduction compared to conventional CO2 extraction. These results highlight the potential of SFE-CO2 using membrane filtration as a sustainable alternative for industrial sunflower oil production, addressing both environmental and health concerns associated with the use of hexane.