Circular economy in the olive sector: valorization of pruning waste using sustainable processes based on the use of high-pressure technology

Resumen

The generation of agri-food waste is a global concern that generates problems for the economy,the environment, human health and society. The olive (Olea europaea L.) industry generates largevolumes of solid waste from olive trees, including seeds, pulp, and pruning residues. The growingolive trees and oil extraction produce substantial quantities of olive leaves throughout the year. Anaverage, 25 kg of by-products (leaves and twigs) are produced annually per olive tree [1], and alarge amount (about 10 % of fruit weight) is separated from the fruits during oil extraction [2]. Oliveleaves are mainly used for animal consumption, biomass production or incineration. However, theyare rich in numerous bioactive compounds such as oleuropein, hydroxytyrosol, oleoside, luteolinand phenolic acids (i.e., verbascoside) that have demonstrated important biomedical propertiessuch as antiviral, antimicrobial, anti-inflammatory, antioxidant, and anti-Alzheimer activities [3, 4].Therefore, considering the valuable profile of olive leaves as a source of compounds withtherapeutic properties, sustainable practices to promote the reuse of olive leaf waste from olive oil production towards the extraction of these compounds are in demand. The objective of this work was to analyze the use of pruning residues to obtain extracts with potent biological activity using high-pressure techniques. In turn, this extract was the raw material in the impregnation process to obtain new materials with antioxidant and antimicrobial properties that can be applied in the food and/or biomedical industry. The transfer of the results obtained to the Andalusian olive sector will allow minimizing the volume of waste and introducing new lines of business in the agri-food sector.