Browsing by Author "Gomes, Vera"
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- Antioxidant activity of thyme waste extract in O/W emulsionsPublication . EL-GEUNDOUZ, Soukaina; AAZZA, Smail; Anahi Dandlen, Susana; MAJDOUB, Nesrine; Lyoussi, Badiaa; Raposo, Sara; Antunes, Maria Dulce; Gomes, Vera; Miguel, MariaThymus vulgaris (thyme) is an aromatic plant and its essential oil has been applied as antimicrobial and antioxidant due to the presence of phenolic compounds. However, after steam distillation, the deodorized plant material is rejected, despite the possible presence of bioactive compounds. Ethanolic thyme waste extract revealed the presence of benzoic acid, 4-hydroxybenzoic acid, ferulic acid, caffeic acid, and sinapic acid. This waste thyme extract had the capacity for preventing the formation of primary and secondary lipid oxidation products in emulsions O/W (oil in water), constituted by diverse proportions of wheat and almond oils, without interfering with the viscosity parameters, for 10 weeks, at 37 °C. The increasing proportion of almond oil (≥50%) in the emulsion increases its resistance to oxidation, which is improved with the presence of an optimal concentration of tested thyme waste extract (0.02% and 0.04%). The waste thyme extract can, therefore, be used as an antioxidant either in food or pharmaceutical emulsions O/W, replacing the synthetic antioxidants.
- Batch studies on the biodegradation potential of Paracetamol, Fluoxetine and 17α-Ethinylestradiol by the Micrococcus yunnanensis Strain TJPT4 recovered from marine organismsPublication . Da Luz Palma, Tânia Cristina; Valentine, Julia; Gomes, Vera; Faleiro, L; Costa, MariaThe emerging pollutants paracetamol, fluoxetine and ethinylestradiol are inefficiently removed by conventional wastewater treatments, entering in aquatic environments in which they are hazardous. Aiming for the obtention of bacteria with the capacity for environmental bioremediation, eight bacteria were isolated from two consortia recovered from Hymedesmia versicolor and Filograna implexa marine organisms which exhibited a high-paracetamol-removal capacity. The isolates that displayed the ability to grow in the presence of 100 mg/L paracetamol as the sole carbon source were assigned to Paenibacillus, Micrococcus and Microbacterium genera. The isolate assigned to the Micrococcus yunnanensis strain TJPT4 presented the best performance, degrading 93 ± 4% of 15 mg/L paracetamol as the sole carbon source after 360 h, and was also apparently able to degrade the produced metabolites. This strain was able to remove 82.1 ± 0.9% of 16 mg/L fluoxetine after 504 h, mainly by adsorption, but apparently a biodegradation contribution also occurred. This strain was able to remove 66.6 ± 0.2% of 13 mg/L 17α-ethinylestradiol after 360 h. As far as is known, Micrococcus yunnanensis is for the first time recovered/identified in Filograna implexa, presenting a high drug removal efficiency, thereby becoming a great candidate for treatment processes (e.g., bioaugmentation), especially in the presence of saline intrusions.
- Natural antioxidants in emulsions O/WPublication . EL-GEUNDOUZ, Soukaina; Azza, S.; Dandlen, Susana Anahi; MAJDOUB, Nesrine; Lyoussi, Badiaa; Raposo, Sara; Gomes, Vera; Bankova, Vassya; Popova, Milena; Antunes, Maria Dulce; Miguel, Maria GracaThis study compared the capacity of propolis extract (PE) and thyme waste extract (TWE) to prevent the oxidation of oil in water (O/W) emulsion, as well as their impact on emulsion apparent viscosity (AV) in the presence of wheat germ and almond oils as lipid phase. For this, central composite design (CCD) and principal component analysis (PCA) were performed. Oxidation process was monitored by evaluating the formation of primary and secondary lipid oxidation products, at the same time the AV behavior was determined evaluating consistency index and flow behavior index. The results revealed that the increase of PE% and TWE% decreases TBARS (Thiobarbituric Acid Reactive Substances) and hydroperoxides formation. Viscosity increases with the rise of TWE% over (0.04%), whereas lower concentrations of PE% decreases it. Those results have been confirmed in the PCA analysis. TWE showed higher resistance to oxidation, although PE was more effective as antioxidant than TWE.