Clean Extraction Methodologies for High-Added-Value Olive Oil Production and Whole Valorization of the Olive Fruit

Olive oil production is an economically and culturally important agro-industrial activity, particularly in Mediterranean regions, but conventional extraction processes generate significant quantities of by-products and may lead to the loss of valuable bioactive compounds. In this context, improving extraction efficiency while preserving oil quality and promoting sustainable processing has become a major research focus. This review examines the composition of virgin olive oil with particular attention to minor bioactive compounds and discusses how conventional processing technologies influence their distribution and retention. The environmental implications of traditional extraction systems, especially the generation of olive mill wastewater and solid residues, are also addressed. Furthermore, emerging and alternative extraction technologies are analyzed, including screw press (expeller) and supercritical CO2 extraction, highlighting their potential to enhance the recovery of bioactive compounds and reduce environmental impacts. Particular emphasis is placed on water-free or reduced-water extraction approaches and on the valorization of olive mill by-products as part of a circular economy strategy. Overall, innovative extraction technologies can reconcile efficiency, sustainability and quality by minimizing polyphenol losses and wastewater generation, requiring further industrial optimization.