Comparative evaluation of extraction methods for fragrant semen Trichosanthis oil: Cold pressing, conventional solvent, subcritical n-butane and supercritical CO2

The physicochemical properties, chemical compositions, antioxidant activities, and volatile profiles of fragrant Semen Trichosanthis oil (FSTO) extracted by cold pressing (CP), solvent extraction (SE), subcritical <i>n</i>-butane extraction (SBE), and supercritical CO₂ extraction (SPE) were systematically investigated. Unsaturated fatty acids predominated in the oils (89.57-92.73 %), primarily trichosanic acid, linoleic acid, and oleic acid, with SBE oil containing the highest proportion (92.73 %). CP oil showed the highest phytosterol content (434.72 mg/100 g) and total flavonoid content, alongside the strongest antioxidant activity. In contrast, SBE oil had the greatest total phenolic content (62.08 μg GAE/g) and oxidative stability (1.24 h). All oils exhibited Newtonian flow behavior, with SBE and SPE oils exhibiting the lowest activation energy. A total of 108 volatile organic compounds were identified by gas chromatography-ion mobility spectrometry, with SBE and SPE oils displaying more complex and abundant profiles, while CP oil better retained natural aroma compounds. These results demonstrate that extraction method significantly influences the composition, functionality, and volatile profile of FSTOs. SBE achieved a favorable balance between oil yield, quality, and sustainability.