Valorization of Olive Leaves through Polyphenol Recovery Using Innovative Pretreatments and Extraction Techniques: An Updated Review
Espérance Debs,
Anna-Maria Abi-Khattar,
Hiba N. Rajha,
Roula M. Abdel-Massih,
Jean-Claude Assaf,
Mohamed Koubaa,
Richard G. Maroun,
Nicolas Louka
Affiliations
Espérance Debs
Department of Biology, Faculty of Arts and Sciences, University of Balamand, P.O. Box 100, Tripoli 1300, Lebanon
Anna-Maria Abi-Khattar
Unité de Recherche Technologies et Valorisation Agro-Alimentaire, Centre d’Analyses et de Recherche, Faculté des Sciences, Université Saint-Joseph de Beyrouth, Riad El Solh, P.O. Box 17-5208, Beirut 1104 2020, Lebanon
Hiba N. Rajha
Unité de Recherche Technologies et Valorisation Agro-Alimentaire, Centre d’Analyses et de Recherche, Faculté des Sciences, Université Saint-Joseph de Beyrouth, Riad El Solh, P.O. Box 17-5208, Beirut 1104 2020, Lebanon
Roula M. Abdel-Massih
College of Medicine, Central Michigan University, 1280 East Campus Dr, Mount Pleasant, MI 48858, USA
Jean-Claude Assaf
Department of Chemical Engineering, Faculty of Engineering, University of Balamand, P.O. Box 100, Tripoli 1300, Lebanon
Mohamed Koubaa
ESCOM, TIMR (Integrated Transformations of Renewable Matter), Centre de Recherche Royallieu-CS 60319, Université de Technologie de Compiègne, CEDEX, 60203 Compiègne, France
Richard G. Maroun
Unité de Recherche Technologies et Valorisation Agro-Alimentaire, Centre d’Analyses et de Recherche, Faculté des Sciences, Université Saint-Joseph de Beyrouth, Riad El Solh, P.O. Box 17-5208, Beirut 1104 2020, Lebanon
Nicolas Louka
Unité de Recherche Technologies et Valorisation Agro-Alimentaire, Centre d’Analyses et de Recherche, Faculté des Sciences, Université Saint-Joseph de Beyrouth, Riad El Solh, P.O. Box 17-5208, Beirut 1104 2020, Lebanon
Olive leaves are naturally generated as a by-product during olive harvesting and olive oil production. Usually discarded with no specific use, they are a valuable source of bioactive compounds that should not be overlooked. Their valorization must therefore be achieved through the recovery of their polyphenols using an ecological strategy. Conventional extraction is commonly known as an energy- and solvent-consuming process, whereas emerging and innovative extraction technologies, such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), pulsed-electric-field-assisted extraction (PEF), high-voltage-electric-discharge-assisted extraction (HVED), supercritical fluid extraction (SFE), infrared-assisted extraction (IAE), and “Intensification of Vaporization by Decompression to the Vacuum” (IVDV), are considered more sustainable and environmentally friendly. The aim of this review is to provide a comprehensive and updated overview of the valorization of olive leaves through both pretreatment and extraction techniques via an analysis of the recovered polyphenols and their potential applications.
