Supercritical CO2 Extraction and Purification of Bioactive Compounds in Olive Leaf with Molecularly Imprinted Polymers
Annually, a huge amount of leaves is generated and discarded away as a by-product of the olive oil production. Since, olive leaves are very rich in bioactive compounds, their extraction and isolation could generate added value products useful in the food, chemical and pharmaceutical industries.
Insituto Politécnico de Bragança research in the frame of OLEAF4VALUE project combines the extraction of bioactive compounds in olive leaf using supercritical CO2 with the subsequent processing of the extracts by sorption/desorption in Molecularly Imprinted Polymers (MIPs), aiming at the isolation and purification of target compounds. Supercritical CO2 extractions are performed in a range of operation conditions with temperature between 35 and 50 °C and pressure changing from 100 to 170 bar. Additionally, the presence of a co-solvent is also considered for assessment of their effect on the profile of the extracted compounds. HPLC-DAD and LC-MS are used for the identification/quantification of the bioactive compounds extracted with the different supercritical operation conditions. In this extract, oleuropein and luteolin/luteolin-glucosides are the majority compounds but oleoside, verbascoside and oleanolic acid, among others, are also identified in the different extracts produced.
Moreover, due to the specificity of MIPs towards target compounds and their efficient isolation/purification of bioactive compounds in plant extracts, namely in olive leaf extracts, they are being considered in sorption processes to retain analytes of interest. This research designs and synthesises MIPs to target compounds in olive leaf extracts considering the combination of different functional monomers.
In conclusion, the results obtained show the feasibility of the proposed approach for the valorisation of the olive leaf by-products.
Author: Catarina Gomes, Instituto Politécnico de Bragança