Liquefied Petroleum Gas Extraction: An Innovative, Green, and Sustainable Approach for Extracting Natural Lipophilic Compounds

As an emerging green technique, liquefied petroleum gas (LPG) extraction demonstrates significant advantages for extracting natural lipophilic compounds, including high extraction efficiency, low-temperature operation, minimal solvent residue, easy solvent recovery, low energy consumption, environmental friendliness, and economic viability. This article systematically reviews the principles, equipment, key influencing factors, application cases, and comparisons with other extraction technologies, while also analyzing its safety, sustainability, and industrial potential. LPG (primarily composed of propane and butane) enables efficient extraction under mild pressure (0.5–3.5 MPa) and low temperature (20–40°C) due to its low polarity, low boiling point, and high diffusivity, effectively preserving thermolabile compounds. In contrast to supercritical CO₂ extraction, LPG reduces equipment costs by 30–50% and energy consumption by 40%. Compared with n-hexane, LPG exhibits lower toxicity and minimal solvent residue. Although LPG has limitations in extracting polar compounds, its applicability can be expanded by adding polarity modifiers (e.g., ethanol) or optimizing process parameters (e.g., temperature and pressure). Future research should focus on developing LPG polarity modification techniques, improving safety measures, integrating with other green technologies, and overcoming industrialization barriers to facilitate large-scale applications in food, pharmaceutical, and cosmetic industries.