Bioactive extracts of orange (Citrus sinensis L. Osbeck) pomace obtained by SFE and low pressure techniques: Mathematical modeling and extract composition

The objective of this study was to obtain orange (Citrus sinensis L. Osbeck) pomace extract using supercritical fluid extraction (SFE) with CO₂ and with CO₂ and co-solvent. In order to evaluate the high pressure method in terms of process yield, extract composition and biological activity, low pressure methods were also applied to obtain orange extracts, such as ultrasound (UE) and soxhlet (SOX), with different organic solvents, and hydrodistillation (HD). The SFE conditions were temperatures of 313.15 K and 323.15 K and pressures from 100 to 300 bar. The SFE kinetics and mathematical modeling of the overall extraction curves (OEC) were also investigated. The antioxidant potential of the extracts was evaluated by the DPPH method, by the Folin-Ciocalteau method and by the β-carotene/linoleic acid bleaching method. The antimicrobial activity of the extracts was also studied. The main compounds identified were l-limonene, palmitic and oleic acids, n-butyl benzenesulfonamide and β-sitosterol.