An original approach for lipophilic natural products extraction: Use of liquefied n-butane as alternative solvent to n-hexane

- An original system was developed for using liquefied gases as extraction solvent.
- n-butane is a potential food-compatible solvent for extraction of natural products.
- Computational predictive and experimental studies were compared.
- Safety and efficiency are two essential factors for n-butane extractions.
- Extracts obtained using n-butane are qualitatively equal but quantitatively lower.

Recent trends in food extraction techniques have largely focused on finding solutions that minimize the use of toxic solvents or to find alternatives for n-hexane. As an original solution, a new process for extraction of natural product using liquefied gases has been developed at laboratory scale. The applicability of this new process was demonstrated using n-butane as alternative solvent to n-hexane. Extraction of lipophilic natural products such as carrot oleoresin, caraway aromas and sunflower oil was assessed using liquefied n-butane. COSMO-RS simulations allowed determination of the relative solubility of the lipophilic compounds in liquefied n-butane and n-hexane. This theoretical approach was validated with extraction experiments on carrots, caraway seeds and sunflower seeds. Compositions of the extracts were comparable but the extract yields were lower using n-butane. For example the extraction yields were, with n-butane and with n-hexane respectively, 36.9% and 53.4% for sunflower seeds oil, 10.9% and 15.0% for caraway seed essential oil, 25.7% and 55.8% for carrots oleoresin. However the extracts obtained by using n-butane are directly free of solvents and also food grade, as it is an authorized solvent for foodstuff production.