Alternative oil extraction methods from Echium plantagineum L. seeds using advanced techniques and green solvents

- New eco-friendly oil extraction methods using hexane-free processing of Echium seeds.
- PLE using ethanol (10 min) achieved same echium oil yields than hexane Soxhlet.
- UAE optimized method provided a high oil yield under mild conditions (55 °C).
- MAE is a fast alternative achieving acceptable results in only 1-2 min.
- No reduction in omega-3 content in oils was found using advanced extraction techniques.

The edible oil processing industry involves large losses of organic solvent into the atmosphere and long extraction times. In this work, fast and environmentally friendly alternatives for the production of echium oil using green solvents are proposed. Advanced extraction techniques such as Pressurized Liquid Extraction (PLE), Microwave Assisted Extraction (MAE) and Ultrasound Assisted Extraction (UAE) were evaluated to efficiently extract omega-3 rich oil from Echium plantagineum seeds. Extractions were performed with ethyl acetate, ethanol, water and ethanol:water to develop a hexane-free processing method. Optimal PLE conditions with ethanol at 150 °C during 10 min produced a very similar oil yield (31.2%) to Soxhlet using hexane for 8 h (31.3%). UAE optimized method with ethanol at mild conditions (55 °C) produced a high oil yield (29.1%). Consequently, advanced extraction techniques showed good lipid yields and furthermore, the produced echium oil had the same omega-3 fatty acid composition than traditionally extracted oil.

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