title: Optimization of a green extraction method for the recovery of polyphenols from olive leaf using cyclodextrins and glycerin as co-solvents.
abstract: Olive leaf, an agricultural by-product, was studied for the valorization of its biophenols using green extraction techniques; i.e. non-toxic and eco-friendly extraction solvents were used, involving water and glycerol. 2-hydroxypropyl-β-cyclodextrin (CD), was also employed as an enhancer of the extraction, since cyclodextrins (CD's) are known to improve the extractability of olive leaf polyphenols by forming water soluble inclusion complexes. The process was optimized by implementing a central composite (Box-Behnken) experimental design and response surface methodology, taking into consideration the following independent variables: glycerol concentration (Cgl), CD concentration (CCD) and temperature (T). The evaluation of the extraction model was based on two responses: the total polyphenol yield (YTP) and the antiradical activity (AAR). Optimum values for the extraction process were obtained at 60% (w/v) glycerol content, T = 60 °C and 7% (w/v) CD content. LC-MS analysis was also applied in order to characterize the polyphenolic composition of extracts containing cyclodextrins. The main polyphenols present were oleuropein and oleuropein derivatives. Olive leaf aqueous extracts containing glycerol and cyclodextrins may be used as raw materials/ingredients for several end-users in the food, cosmetic and pharmaceutical industries.
authors.affiliation: Department of Food Science and Technology, Faculty of Agriculture, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Mourtzinos
authors.affiliation: Department of Food Science and Technology, Faculty of Agriculture, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Anastasopoulou
authors.affiliation: Department of Food Science and Technology, Faculty of Agriculture, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
authors.forename: Athanasios
authors.initials: A
authors.lastname: Petrou
authors.affiliation: Food Quality and Chemistry of Natural Products, Mediterranean Agronomic Institute of Chania (M.A.I.Ch.), 73100 Chania, Greece.
authors.forename: Spyros
authors.initials: S
authors.lastname: Grigorakis
authors.affiliation: School of Environment, University of the Aegean, Mitr. Ioakim Street, Myrina, 81400 Lemnos, Greece.
authors.forename: Dimitris
authors.initials: D
authors.lastname: Makris
authors.affiliation: Department of Food Science and Technology, Faculty of Agriculture, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
authors.forename: Costas G
authors.initials: CG
authors.lastname: Biliaderis
keywords: Cyclodextrins; Extraction; Inclusion complex formation; LC–MS analysis; Polyphenols