Enhancing sustainability and quality: A comparative study of sunflower seed oil extraction methods and physico-chemical characterization

Abstract

This study explores the potential of supercritical carbon dioxide (SC-CO₂) as a sustainable alternative to conventional solvent-based extraction for sunflower seed oil. SC-CO₂ extraction provides a safer, cleaner approach, yielding high-quality oil without using toxic solvents. This research compares the physico-chemical properties and fatty acid composition of sunflower seed oil extracted using SC-CO₂ and hexane. SC-CO₂ extraction achieved a higher oil recovery (44.580 ± 0.572 %) than hexane extraction (41.783 ± 0.377 %). Notable differences in oil properties were observed. SC-CO₂-extracted oil had a higher specific gravity (0.949 ± 0.001) than hexane-extracted oil (0.913 ± 0.003), indicating improved functional characteristics. It also demonstrated superior thermal stability, with a higher flash point (320.224 ± 2.128 °C) and fire point (342.325 ± 2.248 °C) compared to hexane-extracted oil (flash point: 317.477 ± 0.467 °C; fire point: 340.786 ± 3.742 °C), making it suitable for food and industrial applications. Additionally, SC-CO₂ extraction preserved a higher total phenolic content (56.730 ± 0.904 mg GAE/100 g) than hexane extraction (49.532 ± 2.077 mg GAE/100 g), leading to greater antioxidant activity (39.140 % vs. 36.553 %). Gas Chromatography analysis confirmed a high unsaturated fatty acid content (89.679 ± 0.079 %), mainly linoleic and cis-oleic acids. SC-CO₂-extracted oil contained more cis-oleic and behenic acids, enhancing oxidative stability and nutritional value. The high cis-oleic acid content (57.713 ± 0.068 %) highlights its versatility in food, pharmaceuticals, and industrial formulations. These results establish SC-CO₂ extraction as a superior method for producing stable, bioactive-rich sunflower oil, reinforcing its role in sustainable processing.