Valorization of olive processing by-products via drying technologies: a case study on the recovery of bioactive phenolic compounds from olive leaves, pomace, and wastewater

Malekjani, Narjes; Jafari, Seid Mahdi

doi:10.1080/10408398.2022.2068123

Cited by 11 publications

(4 citation statements)

References 107 publications

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“…The total phenolic content of OP is significantly high, exhibiting inevitable biotoxicity and phytotoxicity when it is disposed into the environment. Up to now, OP has been used as biofuel or animal feedstock in line with the current regulations, but the increasing demands for olive oil and related products make the amount of biowastes that are accumulated difficult to handle [ 1 , 2 ]. Meanwhile, the market of olive polyphenols is ever growing.…”

Section: Introductionmentioning

confidence: 99%

Valorization of Olive Pomace Using Ultrasound-Assisted Extraction for Application in Active Packaging Films

Fotiadou,

Fragkaki,

Pettas

et al. 2024

IJMS

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Bioactive compounds that can be recovered by the solid wastes of the olive oil sector, such as polyphenols, are known for their significant antioxidant and antimicrobial activities with potential application in nutraceutical, cosmetic, and food industries. Given that industrial demands are growing, and the polyphenol market value is ever increasing, a systematic study on the recovery of natural antioxidant compounds from olive pomace using ultrasound-assisted extraction (UAE) was conducted. Single-factor parameters, i.e., the extraction solvent, time, and solid-to-liquid ratio, were investigated evaluating the total phenolic content (TPC) recovery and the antioxidant activity of the final extract. The acetone–water system (50% v/v, 20 min, 1:20 g mL−1) exhibited the highest total phenolic content recovery (168.8 ± 5.5 mg GAE per g of dry extract). The olive pomace extract (OPE) was further assessed for its antioxidant and antibacterial activities. In DPPH, ABTS, and CUPRAC, OPE exhibited an antioxidant capacity of 413.6 ± 1.9, 162.72 ± 3.36 and 384.9 ± 7.86 mg TE per g of dry extract, respectively. The antibacterial study showed that OPE attained a minimum inhibitory activity (MIC) of 2.5 mg mL−1 against E. coli and 10 mg mL−1 against B. subtilis. Hydroxytyrosol and tyrosol were identified as the major phenolic compounds of OPE. Furthermore, active chitosan–polyvinyl alcohol (CHT/PVA) films were prepared using different OPE loadings (0.01–0.1%, w/v). OPE-enriched films showed a dose-dependent antiradical scavenging activity reaching 85.7 ± 4.6% (ABTS) and inhibition growth up to 81% against B. subtilis compared to the control film. Increased UV light barrier ability was also observed for the films containing OPE. These results indicate that OPE is a valuable source of phenolic compounds with promising biological activities that can be exploited for developing multifunctional food packaging materials.

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Section: Introductionmentioning

confidence: 99%

Valorization of Olive Pomace Using Ultrasound-Assisted Extraction for Application in Active Packaging Films

Fotiadou,

Fragkaki,

Pettas

et al. 2024

IJMS

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“…It is estimated that each liter of olive oil generates 6.23 kg of pruning waste (branches and leaves). The latter represents between 3% and 5% of the biomass that is processed in this industry worldwide, which could exceed 18 million tons per year 2,3 . Currently, the most widespread practice in olive production for disposal of the leaves is to burn them in the field, which significantly increases the risk of fire and environmental pollution.…”

Section: Introductionmentioning

confidence: 99%

Gastrointestinal digestion of olive leaf waste from olive mill production chain in a simulator of the gastrointestinal tract

Martínez‐Navarro,

Escobar‐Talavera,

Cebrián‐Tarancón

et al. 2024

J Sci Food Agric

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BACKGROUNDCurrently, olive leaves are considered waste, although their high phenolic content makes them a source of antioxidants that could be used directly. The aim of this work was to study the behavior of phenolic compounds contained in olive leaf from the olive mill production chain during their gastrointestinal digestion.RESULTSPhenolic compounds in the gastric digestion analyzed by high‐performance liquid chromatography–diode array detection–mass spectrometry increased by 58% to 314.5% compared to the meal, while in the intestinal stage they ranged from 1.87 to 9.04 times higher. An increase of between 187% and 903% in bioaccessibility of phenolic compounds in the intestinal phase was observed, except for verbascoside. Furthermore, such compounds were fully bioavailable, except for apigenin‐7‐O‐glucoside, which showed a bioavailability of 56%.CONCLUSIONThe current study showed that the concentration of oleuropein, apigegin‐7‐O‐glucoside, hydroxytyrosol hexoside and hydroxytyrosol contained in olive leaf continued to be extracted during the gastrointestinal digestion process. Furthermore, the results obtained with respect to their bioaccessibility and bioavailability suggest a good disposition to pass into the bloodstream where they could exert beneficial effects. Therefore, these results are promising for olive leaf becoming a consumable by‐product that could be directly ingested through a simple infusion. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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“…In recent years, agri-food by-products have been increasingly considered for the extraction of bioactive compounds such as antioxidants, vitamins, minerals, dietary fiber, essential fatty acids, oligosaccharides and oligopeptides [3,4]. In the Mediterranean area, a huge amount of waste is generated during the olive oil production process [5].…”

Section: Introductionmentioning

confidence: 99%

Characterization and Biological Activities of In Vitro Digested Olive Pomace Polyphenols Evaluated on Ex Vivo Human Immune Blood Cells

et al. 2023

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Olive pomace (OP) represents one of the main by-products of olive oil production, which still contains high quantities of health-promoting bioactive compounds. In the present study, three batches of sun-dried OP were characterized for their profile in phenolic compounds (by HPLC-DAD) and in vitro antioxidant properties (ABTS, FRAP and DPPH assays) before (methanolic extracts) and after (aqueous extracts) their simulated in vitro digestion and dialysis. Phenolic profiles, and, accordingly, the antioxidant activities, showed significant differences among the three OP batches, and most compounds showed good bioaccessibility after simulated digestion. Based on these preliminary screenings, the best OP aqueous extract (OP-W) was further characterized for its peptide composition and subdivided into seven fractions (OP-F). The most promising OP-F (characterized for its metabolome) and OP-W samples were then assessed for their potential anti-inflammatory properties in ex vivo human peripheral mononuclear cells (PBMCs) triggered or not with lipopolysaccharide (LPS). The levels of 16 pro-and anti-inflammatory cytokines were measured in PBMC culture media by multiplex ELISA assay, whereas the gene expressions of interleukin-6 (IL-6), IL-10 and TNF-α were measured by real time RT-qPCR. Interestingly, OP-W and PO-F samples had a similar effect in reducing the expressions of IL-6 and TNF-α, but only OP-W was able to reduce the release of these inflammatory mediators, suggesting that the anti-inflammatory activity of OP-W is different from that of OP-F.

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Valorization of olive processing by-products via drying technologies: a case study on the recovery of bioactive phenolic compounds from olive leaves, pomace, and wastewater

Cited by 11 publications

References 107 publications

Valorization of Olive Pomace Using Ultrasound-Assisted Extraction for Application in Active Packaging Films

Valorization of Olive Pomace Using Ultrasound-Assisted Extraction for Application in Active Packaging Films

Gastrointestinal digestion of olive leaf waste from olive mill production chain in a simulator of the gastrointestinal tract

Characterization and Biological Activities of In Vitro Digested Olive Pomace Polyphenols Evaluated on Ex Vivo Human Immune Blood Cells

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