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

## TL;DR

This study compares four methods for extracting oil from fragrant Semen Trichosanthis, finding that each method affects the oil's composition, antioxidant activity, and aroma differently.

## Contribution

The study provides a comprehensive comparative analysis of four extraction methods for fragrant Semen Trichosanthis oil, highlighting their impact on physicochemical properties and volatile profiles.

## Key findings

- Subcritical n-butane extraction yielded oil with the highest unsaturated fatty acids and oxidative stability.
- Cold pressing produced oil with the highest phytosterol and antioxidant activity.
- Gas chromatography-ion mobility spectrometry identified 108 volatile compounds, with subcritical n-butane and supercritical CO2 methods showing more complex profiles.

## Abstract

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 n-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.

•Four extraction methods for fragrant Semen Trichosanthis oils (FSTOs) were compared.•FSTOs are rich in UFAs, particularly trichosanic acid and linoleic acid.•Cold pressing oil exhibited the highest phytosterol content and antioxidant activity.•Subcritical n-butane extracted oil had the highest phenolics and oxidative stability.•Gas chromatography-ion mobility spectrometry identified 108 volatile compounds.

Four extraction methods for fragrant Semen Trichosanthis oils (FSTOs) were compared.

FSTOs are rich in UFAs, particularly trichosanic acid and linoleic acid.

Cold pressing oil exhibited the highest phytosterol content and antioxidant activity.

Subcritical n-butane extracted oil had the highest phenolics and oxidative stability.

Gas chromatography-ion mobility spectrometry identified 108 volatile compounds.