Saturday, 24 March 2018

Modelling the isothermal degradation kinetics of metrafenone and mepanipyrim in a grape juice analog

Food Research International, 108, 339-346, 2018

Five photodegradation products of metrafenone (MTF) and six of mepanipyrim (MEP) were identified in synthetic grape juice at 25 °C and the structures of the main reaction products established. The degradation of MTF and MEP was modelled by using three different strategies involving monitoring (a) the disappearance of the parent compound, (b) the conversion of the parent compound into its main structurally related reaction products and (c) the degradation of the parent compound to all intermediates and degradation end-products. The kinetic coefficients of degradation for these fungicides were determined and the corresponding half-lives found to be 20.8 h for MFT and 10.1 h for MEP. The proposed models afford reasonably accurate interpretation of the experimental data. Based on the results, modelling the kinetics of disappearance of the parent compound by itself does not ensure the best fit of the degradation behaviour of the fungicides.

Wednesday, 21 March 2018

Nutraceutical Potential of Phenolics from ′Brava′ and ′Mansa′ Extra-Virgin Olive Oils on the Inhibition of Enzymes Associated to Neurodegenerative Disorders in Comparison with Those of ′Picual′ and ′Cornicabra′

Molecules, 23, 722, 2018

The increasing interest in the Mediterranean diet is based on the protective effects against several diseases, including neurodegenerative disorders. Polyphenol-rich functional foods have been proposed to be unique supplementary and nutraceutical treatments for these disorders. Extra-virgin olive oils (EVOOs) obtained from ′Brava′ and ′Mansa′, varieties recently identified from Galicia (northwestern Spain), were selected for in vitro screening to evaluate their capacity to inhibit key enzymes involved in Alzheimer′s disease (AD) (acetylcholinesterase (AChE), butyrylcholinesterase (BuChE) and 5-lipoxygenase (5-LOX)), major depressive disorder (MDD) and Parkinson′s disease (PD) (monoamine oxidases: hMAO-A and hMAO-B respectively). ′Brava′ oil exhibited the best inhibitory activity against all enzymes, when they are compared to ′Mansa′ oil: BuChE (IC50 = 245 ± 5 and 591 ± 23 mg·mL−1), 5-LOX (IC50 = 45 ± 7 and 106 ± 14 mg·mL−1), hMAO-A (IC50 = 30 ± 1 and 72 ± 10 mg·mL−1) and hMAO-B (IC50 = 191 ± 8 and 208 ± 14 mg·mL−1), respectively. The inhibitory capacity of the phenolic extracts could be associated with the content of secoiridoids, lignans and phenolic acids.

Friday, 9 March 2018

Aldehydes as Additives in AOT-based Microemulsions: Influence on the Electrical Percolation

Tenside Surfactants Detergents, 55 (2), 2018, 110-115.

The influence of alkyl-aldehydes upon electric percolation of AOT-based microemulsions has been studied. The number of carbons in the hydrocarbon chain was varied between 0 and 5 atoms (chain length between 0 and 7.33 Å). Two different behaviors were found, while the presence in the microemulsion of short chains aldehydes implies a decrease in the percolation temperature, aldehydes with 4 or 5 carbon atoms in the hydrocarbon chain increase the percolation threshold. This opposite behavior has been justified in terms of aldehyde location in the microheterogeneous system.

Monday, 5 March 2018

Geochemical signatures of the groundwaters from Ourense thermal springs, Galicia, Spain

Sustainable Water Resources Management

Different hot springs and boreholes in the city of Ourense, Galicia, Spain, have been studied to determine the mineral equilibrium conditions of the discharged groundwaters and the reservoir temperatures predicted by the equilibrium conditions. Ourense is located in the Miño River’s valley. The area is characterized by two fault systems, which determine groundwater circulation. A NW trending fault system is the permeable system that transfers groundwater and heat to springs in the Miño River valley as it is evident from the location of the springs in the region. Groundwaters traveling and discharging from granitic and schistose rocks are mainly bicarbonate waters. In comparison, groundwaters traveling and discharging from granodiorite rocks can be bicarbonate, sulfate or chloride waters. Different equilibrium activity diagrams for the dominant cations in groundwater (Na+, K+, Ca2+, Mg2+) have been constructed to correlate water equilibrium conditions with the mineral assemblage, K-feldspar, clinochlore, muscovite, quartz, and calcite. Granites and schists are the rocks within which groundwater circulation approaches mineral equilibrium with equilibrium temperatures around 140–160 °C. Groundwaters circulating throughout granodiorite seem a little bit high in Mg2+ to reach equilibrium conditions. Miño River’s tectonic valley presents strong morphological contrasts in terms of faulting and rock types to the north of the river that allow increased longitude and depth of groundwater circulation. These conditions allow close achievement of water–mineral equilibrium conditions. More research is needed to know the extension of this energy resource and optimize its use.