No abstract

The purpose of this study was to determine the chemical composition of the essential oil of Lavandula officinalis from Morocco using the GC-MS technique and assess the antibacterial effects against seven pathogenic bacteria strains isolated from the food origins of Salmonella infantis, Salmonella kentucky, Salmonella newport, three serotypes of Escherichia coli (O114H8K11, O127K88ac, O127H40K11) and Klebsiella. Tests of sensitivity were carried out on a solid surface using the Disc Diffusion Method. Results showed that E. coli and S.newport were sensitive to Lavandula officinalis essential oil. Minimum inhibitory concentrations (MIC) were determined using the method of agar dilution. The antibacterial results showed that four strains (three serotypes of E. coli, and S. newport) were remarkedly sensitive to Lavandula officinalis essential oil, giving MIC values of 88.7 µg/mL and 177.5 µg/mL. The molecular docking of the main oil products with the E. coli target protein 1VLY, showed that eucalyptol and linalyl acetate bind efficiently with the active site of the target protein. In particular, eucalyptol showed a higher activity than gentamicin used as positive control with a binding energy of −5.72 kcal/mol and −5.55 kcal/mol, respectively.

Microbial adhesion to surfaces is thought to involve physicochemical interactions between the substrate and microbial cells. Understanding the physicochemical aspects involved in the adhesion phenomenon, as a critical step in biofilm formation, is essential to finding ways to prevent their formation and control biocontamination risks. The aim of this study was to investigate the relation between the adhesion behavior of 12 Escherichia coli strains isolated from food and their surface hydrophobicities using qualitative ( θ w ) and quantitative (ΔGiwi) approaches. The surface physicochemical properties of both bacterial cells and glass material were estimated through contact angle measurements. The adhesive behavior of E. coli strains on a glass surface was assessed. The results showed a good logarithmic relation between the percentage of the adhered cells and their surface hydrophobicity with the quantitative approach ΔGiwi; however, qualitative hydrophobicity ( θ w ) appeared to demonstrate no effect regarding adhesion behavior. This work lays the foundation for future studies and opens an important debate on the mechanisms underlying the adhesion behavior of E. coli strains by using the thermodynamic approach (ΔGiwi) as an important model of hydrophobicity that could explain and predict better bacterial adhesion ability.

Figs are a traditional pantry staple for healthy eating in Middle Eastern and North African countries as fig trees grow abundantly in such hot and dry climates. Despite the importance of this species, chemotypic diversity has gone unheeded and therefore its valorization pathways remain poorly documented. For this reason, high-pressure liquid chromatography (HPLC) alongside vibrational spectroscopy were used to investigate the changes of antiradical potency and primary and secondary metabolites in fresh figs with regard to the combined effect of the cultivar factor and the fruit peel chromatic coordinates. Fourier-transform infrared spectroscopy (FTIR) fingerprinting displayed six major peaks assigned to functional groups of the investigated samples with significant differences in their vibration intensities. Biochemical screening revealed highly significant variability (p < 0.05) among the investigated cultivars. Antioxidant activity was found to be higher in free radical scavenging using 2,2-diphenyl-1-picrylhydrazyl (DPPH) compared to ferric reducing ability (FRAP). Chemometric investigations of both biochemical and FTIR fingerprinting showed satisfactory resolutions, and the total phenol contents and chromatic coordinates had the highest scores in the dataset. However, the cultivars’ geographical origin seemed not to have a clear impact on the clustering results. The aforementioned analytical procedures were found to be equally important and can be jointly used for high-resolution screening and discrimination of fig trees.

Citrus peels are known as rich source of bioactive compounds. Therefore, the establishment of an appropriate and innovative extraction method is a major interest to the food processing industry. The aim of this work is to assess the total phenolic content (TPC) and antioxidant activity (AA) of peels extracts prepared from five Moroccan clementine varieties. Extracts were prepared with microwave-assisted extraction (MAE) technique using acetone and methanol solvents. The evaluation of the antioxidant activity was performed by DPPH and ABTS- free radical scavenging. The extraction conditions had significant effects on total phenolic content (TPC) and antioxidant activity (AA). In fact, the highest TPC amount of clementine varieties (730.850±0.004mg GAE/100g DM) was obtained with acetone solvent for the Sidi Aissa variety. Regarding antioxidant activity, results with DPPH method showed an important antiradical and antioxidant activities for Sidi Aissa variety with methanol solvent (46.30± 1.01%) . However, ABTS method showed a good antioxidant activity for Ain Taoujdat with methanol solvent (3.02 mg/100g DM). This work provided to study the biochemical quality of Moroccan clementine extracts obtained by two microwave-assisted extraction processes in order to investigate further industrial potential uses in agro-food and pharmaceutical industries