Consumption of wild mushrooms has increased in recent years; however, not all of them are edible and there is no precise information on those that may cause poisoning. Therefore, studies to obtain ...data about their toxicity are needed. For this purpose, we used the brine shrimp Artemia franciscana, a crustacean employed in toxicity tests and with wide application in the toxin detection, including mycotoxins. Mushrooms were collected in the state of Jalisco, Mexico, with which aqueous extracts were prepared. Dilutions of the stock solution of each extract were made to final concentrations of 50, 100, 250, 500, and 1000 µg/mL. Potassium dichromate (PD) was used as positive control and artificial seawater as negative control. The median lethal dose (LD50) of extracts on nauplii of A. franciscana was calculated. The aqueous extracts obtained from Amanita amerivirosa, A. muscaria, Chlorophyllum molybdites, and Leucopaxillus amarus showed a LD50 < 70 µg/mL, similar to PD (LD50 = 37 µg/mL). This is the first indication of the probable toxicity of Leucopaxillus amarus in humans. Cantharellus cibarius and Scleroderma texense caused the lower toxicity to the nauplii. The brine shrimp bioassay was effective in evaluating the toxicity of Basidiomycota. Scleroderma texense has been reported to be toxic, but it was not for this crustacean nauplii, and probably not to humans either, as recent literature has reported.
The Argentine Tierra del Fuego comprises part of the roughly east‐west trending southern end of the Andean Cordillera intensely deformed since the Mesozoic. Mesostructures have been measured in Late ...Jurassic to Miocene rocks. Taking into account statistical criteria to provide a representative stress tensor from a fault population, this study defines 28 paleostress tensors pertaining to 22 sites. The orientation of σ1 shows two main modes trending E‐W to ESE‐WNW and NE‐SW. In addition, extensional sites reveal N‐S, NE‐SW, ESE‐WNW, and NW‐SE horizontal σ3 and vertical σ1. The stress fields obtained are congruous with a regional NE‐SW compressive stress direction active in the study zone since the Late Cretaceous. Shortening was coeval with a 30° counterclockwise rotation of the Patagonian orogenic curve and the indentation of the orogenic wedge against a basement high, the Río Chico Arch, up to the early Miocene. The indentation caused a modification in the orientation of the compressive stress trajectories, showing NE‐SW direction in Sorondo Range sector and NW‐SE in Mitre Peninsula area. Since the late Miocene, left‐lateral activity along the Magallanes‐Fagnano Fault System produced local deviations of the NE‐SW compressive stress toward an E‐W direction. The present‐day stress field is also characterized by NE‐SW subhorizontal P axis derived from earthquake focal mechanisms and geodetic studies.
Key Points
Brittle mesostructures analysis contributes to establish the geodynamic evolution of the Fuegian Andes area
The stress fields establish are congruous with a regional NE‐SW compressive stress direction active in the zone since the Late Cretaceous
Deflection of the regional stress field by large crustal heterogeneities controlled the local structures
Tea (Camellia sinensis) is an evergreen shrub that is recognized worldwide for its functional properties. The current global production of green tea is approximately 5.3 million tons per year. Green ...tea processing has severely affected the generation of agro-industrial waste. One strategy for reducing waste accumulation is the revalorization of agro-industrial wastes via solid-state fermentation (SSF). The aim of this study was to valorize green tea processing residues to produce tannase under SSF using an endemic strain from Western Ghats, Aspergillus niger TBG 28A. SSF was performed in Erlenmeyer flasks with spent green tea leaves inoculated with spores of A. niger TBG 28A. Bioprocess optimization was carried out by employing the Box–Benkhen experimental design, achieving a high enzymatic yield of 246.82 (U/g). The present study shows the complexity of the degradation of tannins and the different patterns of expression of fungal tannase obtained from A. niger TBG 28 A. The enzyme was further purified to obtain a fold purification of 16.35% and a molecular mass of 150 kDa. Producing tannase with a novel strain of A. niger TBG 28A is an interesting strategy to revalorize green tea waste.
The frost of olives on the tree due to drops of temperature can produce sensory defects in virgin olive oil (VOO). Temperature changes can be abrupt with freeze–thaw cycles or gradual, and they ...produce sensory and chemical variations in the oil. This study has analyzed the quality parameters (free fatty acids, peroxide value, UV absorption, and fatty acid ethyl esters) and phenols of VOOs described with the ‘frostbitten olives’ sensory defect. The phenol profiles allowed grouping these VOOs into two types. One of them, characterized with “soapy” and “strawberry-like” aroma descriptors, had higher values of 1-acetoxypinoresinol, pinoresinol, and aldehydic form of the ligstroside aglycon. The other one, characterized with “wood” and “humidity” descriptors, had higher concentrations of luteolin and apigenin. Most VOOs (75%) from the first group, associated with abrupt drops of temperature, have concentration of phenols higher than the value established by the health claim on olive oil polyphenols approved by the European Commission.
Abstract
The organoleptic assessment (Panel test) is the only procedure within the official methods for determining the quality of virgin olive oils that involves an expert panel. There is an urgent ...need for analytical methodology that can reliably measure volatile compounds in virgin olive oils that is capable of supporting and anticipating the official Panel test. For this reason, a new method based on solid‐phase microextraction–gas chromatography with the choice of two possible detectors (FID or MS) was subjected to a large international interlaboratory validation study. The study involved a two‐stage process: first, a pretrial phase in which 7 participants were exposed to the method for the first time to identify any initial problems with the methodology; then, a formal validation stage (trial proper), which involved 20 laboratories from Europe, USA, Japan and China. The performance of the different detectors was investigated. While both methods have advantages, the method using FID provided better results for 11 compounds, in terms of reproducibility, compared to MS. This information will allow to implement the method with accurate information of the method performance depending on the detector used.
Practical applications: This study provides information from an interlaboratory validation of a method for measuring volatile compounds in virgin olive oils conducted with laboratories (from industry and academia) working in the olive oil sector. The information on the expected analytical errors in the determination of each volatile compound is necessary to apply this method for supporting the official Panel test (sensory analysis). The SPME‐GC‐MS/FID methods proposed in this work can be used for the internal quality control of a company/distributor/quality control laboratory and could also be used in cases of difficult/contradictory organoleptic assessment, or to confirm results from sensory panels in cases of disputes/disagreement (Reg. EU 2022/2105).
Key Points
A continuous high‐density body is regarded as exhumed mantle rocks beneath the Basque‐Cantabrian Basin extending along the Northern Pyrenees
Pedreira et al. () doubts our 3‐D gravity ...model, the view of the high‐density body as exhumed mantle, and the proposed geodynamic model
We defend point by point our model that offers important keys to understand the extension and inversion of the North Iberian Margin
Virgin olive oil (VOO) decays in quality properties during aging, so aged VOOs may have detectable undesirable sensory descriptors in comparison with oils recently extracted. For that reason, ...freshness has become a parameter of paramount importance to maintain the highest standard levels within the period indicated in the “best before” date. However, it is important to note that freshness of VOOs is not necessarily related to its sensory quality. Pigments have been suggested for tracing aging of VOO, and pyropheophytin a (PPP) seems to be the most promising molecule for this task. A predictive model has been used to estimate %PPP in VOO stored at different worldwide locations characterized with different temperatures. The recorded average temperatures, on a monthly basis, were inputs of the predictive model. The results show the influence of temperature in %PPP and how this molecule could serve as a better monitor of the storage period of VOOs. The initial value of %PPP in the oil could help to carry out the storage traceability. This information would be of interest for producers, sellers, and inspection agencies.
In this work, we present an electrochemical study of the boron cage monomercaptoundecahydro-
-dodecaborate B
H
SH
in solution and in a self-assembled monolayer over a polycrystalline gold electrode. ...Cyclic voltammetry of the anion B
H
SH
in solution showed a shift in the peak potentials related to the redox processes of gold hydroxides, which evidences the interaction between the boron cage and the gold surface. For an Au electrode modified with the anion B
H
SH
, cyclic voltammetry response of the probe Fe(CN)
/Fe(CN)
showed a ΔEp value typical for a surface modification. Electrochemical impedance spectroscopy presented
and C
values related to the formation of a self-assembled monolayer (SAM). A comparison of electrochemical responses of a modified electrode with thioglycolic acid (TGA) reveals that the boron cage B
H
SH
diminishes the actives sites over the Au surface due to the steric effects. Differential capacitance measurements for bare gold electrode and those modified with B
H
SH
and (TGA), indicate that bulky thiols enhance charge accumulation at the electrode-solution interface. In addition to electrochemical experiments, DFT calculations and surface plasmon resonance measurements (SPR) were carried out to obtain quantum chemical descriptors and to evaluate the molecular length and the dielectric constant of the Boron cage. From SPR experiments, the adsorption kinetics of B
H
SH
were studied. The data fit for a Langmuir kinetic equation, typical for the formation of a monolayer.
Competition and interaction phenomena among volatiles during their adsorption process by solid phase microextraction (SPME) fibers in static headspace sampling procedure (SHS) cast doubt on its ...ability to quantify virgin olive oil volatiles. SPME fibers being excellent traps, their use was analyzed with a new device allowing the concentration of volatiles in a dynamic headspace sampling procedure (DHS). A central composite experimental design optimized the main variables of the device (4 g sample weight, 40 °C temperature, 150 mL/min flow rate, 50 min adsorption time), while values of the analytical quality control parameters of the method (repeatability, limits of detection and quantification, working range, sensitivity, and resolution) were compared with those ones from static headspace. DHS shows better precision results for aldehydes and alcohols than SHS and allowed analyzing higher concentrations with no problem of saturation. In 19 of 28 compounds analyzed in 50 samples the chromatographic areas were higher when running DHS. The concentration values of volatile compounds in these samples after applying SHS and DHS are discussed together with the ability of the new method for distinguishing virgin olive oil by their categories (extra virgin, virgin, and lampante) by the volatiles quantified in commercial oils.
•A new differential temperature sensor topology is proposed.•New features: digital offset compensation.•May offer both wide dynamic range and high sensitivity.•Suited applications (but not restricted ...to): test/characterization of RF and MMW analogue circuits, measurement of temperature gradients within integrated circuits.•Detailed characterization of thermal offset is presented.
The goal of this paper is twofold: first to add together all different causes that can alter the offset of a differential temperature sensor and, second, to present a new differential temperature sensor architecture that can digitally compensate for this behavior and therefore extends the sensor dynamic range. Measurements performed on a 65nm CMOS differential temperature sensor are presented to illustrate the discussion. As evolution of the state of the art, an automatic calibration procedure and the new sensor topology is presented. With this new topology, not only the thermal offset can be digitally calibrated, but the application field of differential temperature sensors is widened, being now suitable for use in measurements where both wide input range and high differential sensitivity are required.
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