The Efficient Extraction of β-Carotene from Sea Buckthorn Berries Using a Novel Solvent, Fatty Acid Ethyl Esters, and a Combination of Ultrasound and Microwave

The move towards environmentally friendly processing has been a driving force for research into green methods for the extraction of bioactive compounds from plant materials. In this study, a green and efficient process for the extraction of β-carotene from sea buckthorn berries through the simultaneous use of ultrasound and microwave, using a novel green solvent, fatty acid ethyl esters (FAEE), is described. For the same extraction time (45 min), the β-carotene content in the extract was significantly increased (according to ANOVA analysis—p < 0.05) by the simultaneous use of ultrasound and microwave, compared with the separate use of these technologies—an increase of 15 and 89% compared with ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE), respectively. The resulting extract can be used directly, without further purification, as a food supplement because the solvent itself is safe for consumption. Furthermore, FAEE contains omega-3 and omega-6 fatty acids which add to the health benefits of the extract. When β-carotene is extracted from the plant matrix, it is subjected to degradation due to oxidation, but the addition of the antioxidant vitamin E (13 mg/mL of extract) to the extract extends its stability to more than 90 days at room temperature even when exposed to light. The addition of vitamin E also enhances the health benefits of the extract.