Recovery of Bioactive Phenolic Compounds from Lemon (Citrus limon (L.) Burm. f.) and Orange (Citrus Sinensis L. Osbeck) Pomaces

Abstract

Supercritical Fluid Extraction (SFE) from lemon (Citrus limon (L.) Burm. f.) and orange (Citrus Sinensis L. Osbeck) pomaces was applied to obtain extracts with high phenolic content and potent antioxidant activity. The effects of extraction conditions on SFE were analyzed, temperature (40 – 60°C), pressure           (100 – 200 bar), co-solvent (25% (v/v), ethanol) for lemon pomace and pressure effect (100 – 200 bar) on SFE was investigated at 40°C in the presence of 25% (v/v) ethanol for orange pomace using the samples were 100 – 200 µm of average particle size. Moreover, in order to compare experimental data obtained by SFE, Soxhlet extractions were performed using methanol. Total phenolic contents, total flavonoid contents and antioxidant potential of extracts were assessed with Folin-Ciocalteu method, AlCl₃/NaNO₂ colorometric procedure and DPPH method, respectively. Experimental results showed that SC-CO₂ extraction allows obtaining phenolic extracts have antioxidant activity but it presents lower yield than soxhlet extraction. In SFE process, the highest extraction yield determined at the conditions of 100 bar, 50°C and 200 bar, 40°C for lemon and orange pomaces, respectively. Despite the lower extraction yields, SFE is considered as an alternative green technology which provides extensive advantages on the extraction of natural compounds.

Keywords: Lemon, Orange, Supercritical fluid extraction, Antioxidant activity, Phenolic content, Reuse of waste