A green approach to phenolic compounds recovery from olive mill and winery wastes

• Published in: The Science of the total environment Vol. 835; p. 155552
• Main Authors: Tapia-Quirós, Paulina, Montenegro-Landívar, Maria Fernanda, Vecino, Xanel, Alvarino, Teresa, Cortina, José Luis, Saurina, Javier, Granados, Mercè, Reig, Mònica
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 20.08.2022
• Subjects: Circular economy; Olive pomace; Phenolic compounds; Solid-liquid extraction; Wine lees; Circular economy; Phenolic compounds; Solid-liquid extraction; Olive pomace; Wine lees
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.155552

The aim of this study was to evaluate the recovery of phenolic compounds from olive mill and winery wastes by conventional solid-liquid extraction (SLE) using water as the extraction solvent. The studied variables were extraction time (5–15 min), temperature (25–90 °C), solid-to-liquid ratio (1:10–1:100 (kg/L)), pH (3−10) and application of multiple extractions (1–3). The extraction efficiency was evaluated in terms of total phenolic content (TPC), determined by high performance liquid chromatography (HPLC-UV), but also from the recovery of some representative phenolic compounds. The optimized conditions were one extraction step, 10 min, 25 °C, 1:30 (kg/L), pH 5 for olive pomace, and one extraction step, 10 min, 70 °C, 1:100 (kg/L), pH 5 for winery residues. The extraction method is simple and suitable for scaling-up in industry, and the aqueous extracts are fully compatible with further purification schemes based on the use of membranes or resins. The optimized technique was applied to a set of different representative residues from olive mill and winery industries, to assess their suitability as sources for phenolic compounds recovery. The phenolic content in the extracts was evaluated by chromatographic analysis and by the Folin–Ciocalteu assay (FC). Furthermore, the antioxidant capacity was determined by 2,2-azinobis-3-etilbenzotiazolina-6-sulfonat (ABTS), 2,-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Because of their high contents in phenolic compounds and great antioxidant capacity, olive pomace and lees filters were identified as especially suited sources for phenolic compounds recovery. [Display omitted] •Phenolic compounds were recovered from olive mill and winery wastes.•A sustainable and simple solid-liquid (S/L) extraction with water was proposed.•10 min, 25 °C, 1:30 (w/v), pH 5 were the optimal conditions for olive pomace.•The optimized conditions for wine waste were 10 min, 70 °C, 1:100 (w/v), pH 5.•The antioxidant capacity of the recovered phenolic compounds was determined.