Teses de Mestrado ESTiG
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Browsing Teses de Mestrado ESTiG by advisor "Abdelkader, Benhlima"
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- Evaluation of moist olive pomace as an antimicrobial agent envisaging leather treatmentsPublication . Kebaili, Khadidja; Crugeira, Pedro; Barreiro, M.F.; Abdelkader, BenhlimaThe leather industry faces significant losses due to the impact of antimicrobial resistance on leather products, leading to issues like discoloration, unpleasant odors, and decreased performance. Antimicrobial resistance is a complex problem with implications for public health and various sectors of society, associated with increased morbidity and mortality. The olive oil industry discards valuable compounds found in moist olive pomace, including bioactive polyphenols, presenting an opportunity to utilize them as green, safe, and natural antimicrobial agents. This study aimed to assess the antimicrobial capacity of the moist olive pomace (MOP) and its potential application on leather specimens. The research involved the extraction of three extracts using different concentrations of pasteurized MOP with water as the solvent. The minimum inhibitory concentration against Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538 were determined through microdilution with a colorimetric assay (INT). The study also quantified the effective microbial reductions achieved with promising MOP concentrations and evaluated the antimicrobial activity of the most effective MOP concentration on leather specimens. By investigating the antimicrobial potential of MOP against E. coli and S. aureus, this research aimed to introduce this waste product into the sustainable production chain while improving extraction techniques and exploring its applications in the leather industry. This study investigated the effect of different extracts of moist olive pomace (MOP) on the total phenolic compounds (TPC) content. The dried olive pomace was found to have a TPC of approximately 18315 mg.kg-1 GAE (gallic acid equivalent). The main compound identified was oleuropein, which accounted for around 78% of the TPC, followed by hydroxytyrosol and tyrosol, contributing about 19% of TPC. The extraction of MOP was conducted under different concentrations (128, 31.3, and 24 mg/mL) and optimized conditions (45°C and 180 min), using water as the extraction solvent. The extraction yields obtained were 29.5%, 64%, and 83% for the ratios of 1:5, 1:15, and 1:20 w/v respectively. The extracts' antimicrobial effects on Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus) were evaluated using the minimum inhibitory concentration determined by the microdilution technique. The results showed that both bacteria were inhibited at a concentration of 31.3 mg/ml of MOP extract. Furthermore, the MOP extract at 128 mg/ml concentration demonstrated a maximum microbial reduction of 90.22% for S. aureus and 85.45% for E. coli. Therefore, this concentration was considered the most effective MOP concentration. The antimicrobial activity of the MOP extract at the aforementioned concentration was also evaluated on leather specimens. It was found to exhibit bactericidal activity against both E. coli and S. aureus. Overall, these findings highlight the potential antimicrobial properties of MOP extracts and their potential application in various fields, including the leather industry.