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Background Oleuropein, the main bitter phenolic glucoside responsible for green olive bitterness, may be degraded by the β-glucosidase enzyme to release glucose and phenolic compounds. Results Lactobacillus plantarum FSO1 and Candida pelliculosa L18 strains, isolated from natural fermented green olives, were tested for their β-glucosidase production and activity at different initial pH, NaCl concentrations, and temperature. The results showed that strains produced extracellular and induced β-glucosidase, with a molecular weight of 60 kD. The strains demonstrated their biodegradation capacity of oleuropein, associated with the accumulation of hydroxytyrosol and other phenolic compounds, resulting in antioxidant activity values significantly higher than that of ascorbic acid. The highest production value of β-glucosidase was 0.91 U/ml obtained at pH 5 and pH 6, respectively for L. plantarum FSO1 and C. pelliculosa L18. The increase of NaCl concentration, from 0 to 10% (w/v), inhibited the production of β-glucosidase for both strains. However, the β-glucosidase was activated with an increase of NaCl concentration, with a maximum activity obtained at 8% NaCl (w/v). The enzyme activity was optimal at pH 5 for both strains, while the optimum temperature was 45 °C for L. plantarum FSO1 and 35 °C for C. pelliculosa L18. Conclusions L. plantarum FSO1 and C. pelliculosa L18 strains showed their ability to produce an extracellular and induced β-glucosidase enzyme with promising traits for application in the biological processing of table olives.

Two novel symmetrical macrocycles containing four pyrazolic units, with two different side arms were synthesized and characterized. Their antibacterial activity was investigated by determining the ...

The aim of the present study was to evaluate some technological properties and potential probiotic of 14 Lactobacillus strains isolated from brines of natural fermenting Moroccan Picholine green olive. The brine samples, collected from industrial environments, were analyzed for their Physico-chemical and microbiological properties. The Lactobacillus strains were characterized for their technological and physiological properties. The results obtained showed that the olive brines have an average pH of 4.32, an acidity of 0.61% and chloride contents of 6.42%. LAB and yeasts are the most dominant microorganisms in olive brine samples. The selected Lactobacillus (14 strains) showed low resistance to pH 2 and high resistance to bile salts (up to 2%), with values ranges from 1.98%-4.70% and 63.12%-86.48%, respectively. All the Lactobacillus strains displayed high levels of acidification and can produce β-glucosidase, protease, and cellulase in large amounts. The diacetyl production is detected in five Lactobacillus strains.

Fermented green olives process, occurring in extreme environment characterized by low nutrients and high polyphenols and sodium chloride contents, is dominated by lactic acid bacteria (LAB) and yeasts. The probiotic LAB strains, mostly isolated from various fermented Mediterranean olive varieties and different countries, were Lactobacillus plantarum, Lactobacillus pentosus, Lactobacillus paracasei, Lactobacillus rhamnosus, and Lactobacillus coryniformis. Deep studies on probiotic and safety properties of yeasts need to be developed. Probiotic LAB isolated from fermented olives demonstrated, basing in vitro and in vivo tests, various health beneficial effects, mainly the antibacterial, antifungal, and antiadhesive effects against pathogens, the protective effect against virus infections, anticancer, and metals detoxification activities. Autochthonous or nonautochthonous LAB strains improved the fermentation process, the storage conditions, and the functional property of olives and other food products. The optimization of probiotics selection and application conditions may enhance their health-beneficial effects and technological properties.

International audience; The objective of this work is to study the oleuropein (OLP) biodegradation by a strain of Lactobacillus plantarum FSO175 under conditions (pH 4.5, NaCl 5% and glucose 1%), during 7 days of incubation at 30 °C, in modified MRS broth containing OLP as carbon source. The results obtained, by HPLC analyses, showed that the biodegradation of OLP by L. plantarum FSO175, is accompanied with increase of hydroxytyrosol (HT) content and acidity values. The yields of OLP degradation and HT accumulation are depending on carbon sources, stress conditions and time of incubation. So that, the drastic reduction in OLP biodegradation, obtained at pH 6.7 (trial B), decreased significantly (p

The synthesis of new bipyrazolic ligands functionalized by carboxyl groups, namely 3-Bis(3′-carboxyl-5′-methyl-l'-pyrazolyl) propan-2-ol (L1) and 1,3-Bis(3′-carboxyl-5′-methyl-l '-pyrazolyl),2-methyl propane (L2) is reported. Their corresponding [C13H15CuN4O5] (CuL1) and [C14H16CuN4O4] (CuL2) copper (II) complexes are also elaborated and characterized by elemental analysis, FTIR an UV–visible spectroscopy. The crystal structure of the CuL1 complex confirms that copper atom is 4-coordinated, in a distorted square planar geometry within the molecule, and achieves its coordination through weak intermolecular interactions leading to two dimensional slabs. This geometry is in agreement with UV–visible results which also evidence that structure of complexes are affected in DMSO in contrast to methanol. No antibacterial activity against all the tested bacterial strains has been found for the Cu (II) complexes. By contrast, CuL1 is characterized with good catalytic properties in the air-oxidation of catechol substrate to quinone.