Optimization of oil extraction from Hippophae salicifolia berries using supercritical CO2: Assessment of physicochemical, antioxidant, antibacterial, and thermal properties

Abstract

The oil of Hippophae salicifolia berry contains valuable phytochemicals such as carotenoids, tocopherols, and essential fatty acids, which inhibit microbial growth, chelate metals, and scavenge free radicals. Supercritical carbon dioxide (SC-CO2) is an eco-friendly alternative approach that allows quicker extraction at a reduced temperature. Parameters of SC-CO2 extraction of oil from H. salicifolia berries were optimized to obtain the best oil yield with maximum β-carotene and total tocopherol contents. The optimum extraction condition was found to be 27.02 MPa, 48.46 °C, 16.45 g/min. Extraction at optimum condition resulted in 12.82 ± 1.4% oil yield with 126.67 ± 2.9 mg/100 g oil β-carotene and 679.42 ± 1.3 mg/100 g oil total tocopherol. SC-CO2 and Soxhlet extracted oils contain 42.98% and 41.14% palmitoleic acid, respectively. the total phenolic content of SC-CO2 and Soxhlet extracted oils was 30.13 ± 1.1 mg GAE/g and 24.59 ± 0.09 mg GAE/g, respectively. The antioxidant activity of SC-CO2 oil (1.09 ± 0.06 mg/mL) in the DPPH assay was higher than Soxhlet extracted oil (1.22 ± 0.07 mg/mL). SC-CO2 and Soxhlet extracted oils demonstrated the highest bactericidal activity against S. aureus, with ZoI values of 8.5 ± 0.7 mm and 7 mm, respectively. SC-CO2 extracted oil demonstrated lower thermal stability up to 185 °C but stronger mechanical stress resistance than Soxhlet extracted oil. SC-CO2 extraction of sea buckthorn berry oil is a viable alternative to traditional solvent extraction for use in food, cosmetics, and pharmaceuticals.