Publicação
Development of tailored materials for the valorization of olive leaf and olive oil subproducts through sorption processes
| Resumo: | The increasing demand for sustainable strategies to recover high-value compounds from agro-industrial subproduct has highlighted the potential of olive leaf as a rich yet underexploited resource. This thesis presents the development of cellulose-based molecularly imprinted polymers (MIPs) functionalized with pyridyl groups, designed for the selective extraction of bioactive compounds from olive leaf extracts. Through surface-initiated atom transfer radical polymerization, a total of ten MIPs were synthesized using quercetin and oleanolic acid as templates, along with their corresponding non-imprinted polymers (NIPs), prepared under identical conditions but in the absence of template molecules. Functional monomers were selected based on their compatibility with the target compounds. Characterization of the synthesized sorbents through FTIR, SEM and BET confirmed successful functionalization and surface grafting. The materials were tested in both solid phase extraction and recirculating column systems. Results showed that quercetin-imprinted MIPs exhibited high retention capacity and selectivity for flavonoids, especially in low-polarity solvents like acetonitrile, with statistically significant imprinting factors. In polar media (ethanol/water), retention remained structure-dependent but was largely driven by non-specific interactions. Application with industrial extracts (NATAC OPA 20 and VR2 SS1) demonstrated the capacity of the MIPs to enrich flavonoid glycosides, such as luteolin-7-O-glucoside, with enrichment factors up to 5 in gradient desorption steps. MIP3 was further scaled up and validated under continuous flow, confirming stability, efficiency, and reusability. A second imprinting strategy targeting triterpenoids using oleanolic acid as template was also explored. Although no molecular recognition was observed under tested conditions, the functionalized polymers still improved retention compared to unmodified cellulose, indicating potential for optimization under pH-adjusted systems. Overall, this work proposes a modular and sustainable approach to sorbent design for the valorization of olive leaves. It contributes to the advancement of selective extraction technologies and provides a framework for future applications in circular bioeconomy contexts. |
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| Autores principais: | Gaspar, Rita Martins |
| Assunto: | Molecularly imprinted polymers Olive leaf Selective sorption Bioactive compounds Circular bioeconomy |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Instituto Politécnico de Bragança |
| Idioma: | inglês |
| Origem: | Biblioteca Digital do IPB |
| Resumo: | The increasing demand for sustainable strategies to recover high-value compounds from agro-industrial subproduct has highlighted the potential of olive leaf as a rich yet underexploited resource. This thesis presents the development of cellulose-based molecularly imprinted polymers (MIPs) functionalized with pyridyl groups, designed for the selective extraction of bioactive compounds from olive leaf extracts. Through surface-initiated atom transfer radical polymerization, a total of ten MIPs were synthesized using quercetin and oleanolic acid as templates, along with their corresponding non-imprinted polymers (NIPs), prepared under identical conditions but in the absence of template molecules. Functional monomers were selected based on their compatibility with the target compounds. Characterization of the synthesized sorbents through FTIR, SEM and BET confirmed successful functionalization and surface grafting. The materials were tested in both solid phase extraction and recirculating column systems. Results showed that quercetin-imprinted MIPs exhibited high retention capacity and selectivity for flavonoids, especially in low-polarity solvents like acetonitrile, with statistically significant imprinting factors. In polar media (ethanol/water), retention remained structure-dependent but was largely driven by non-specific interactions. Application with industrial extracts (NATAC OPA 20 and VR2 SS1) demonstrated the capacity of the MIPs to enrich flavonoid glycosides, such as luteolin-7-O-glucoside, with enrichment factors up to 5 in gradient desorption steps. MIP3 was further scaled up and validated under continuous flow, confirming stability, efficiency, and reusability. A second imprinting strategy targeting triterpenoids using oleanolic acid as template was also explored. Although no molecular recognition was observed under tested conditions, the functionalized polymers still improved retention compared to unmodified cellulose, indicating potential for optimization under pH-adjusted systems. Overall, this work proposes a modular and sustainable approach to sorbent design for the valorization of olive leaves. It contributes to the advancement of selective extraction technologies and provides a framework for future applications in circular bioeconomy contexts. |
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