CO₂ Supercritical Fluid Extraction of Oleoresins from Sea Buckthorn Pomace: Evidence of Advanced Bioactive Profile and Selected Functionality

Abstract

The processing of sea buckthorn generates a significant amount of pomace, seeds and skin considered valuable sources of health-promoting macromolecules, such as carotenoids, pectin, flavonoids, phytosterols, polyunsaturated fatty acids and tocopherols. In this study, the bioactives from sea buckthorn pomace (SBP) were extracted using supercritical carbon dioxide (SFE-CO2), at different temperatures and pressures, allowing for obtaining four fractions according to separators (S40 and S45). The highest carotenoid content of 396.12 ± 1.02 mg/g D.W. was found in the S40 fraction, at extraction parameters of 35 °C/45 MPa, yielding an antioxidant activity of 32.10 ± 0.17 mMol TEAC/g D.W. The representative carotenoids in the extract were zeaxanthin, β-carotene and lycopene, whereas all enriched SFE-CO2 extracts contained α-, β- and δ-tocopherol, with α-tocopherol representing around 82% of all fractions. β-sitosterol was the major phytosterol in the fractions derived from S45. All fractions contained significant fatty acids, with a predominance of linoleic acid. Remarkably, the enriched extracts showed a significant palmitoleic acid content, ranging from 53 to 65 µg/g. S40 extracts showed a good antibacterial activity against Staphylococcus aureus and Aeromonas hydrophila ATCC 7966, whereas S45 extracts showed a growth inhibition rate of 100% against Aspergillus niger after three days of growth. Our results are valuable, and they allow identifying the different profiles of extracts with many different applications in food, pharmaceutics, nutraceuticals and cosmeceuticals.

Keywords

• sea buckthorn pomace
• oleoresins
• CO₂ supercritical fluid extraction
• antioxidant activity
• antimicrobial activity