The diverse effects of yeast on the aroma of non-sulfite added white wines throughout aging

Semi-synthetic must containing standard nutrients, a phenolic and aromatic fraction extracted from Albariño grapes and synthetic precursors of 3-mercaptohexanol (MOH) and 4-mercapto-4-pentan-2-one (MMP) were fermented with three different selected commercial S. cerevisiae yeasts. Wines were subjected to anoxic aging at 50 °C for 1, 2, 5 and 8 weeks, and their volatile composition was comprehensively determined by the analysis of 86 different aroma compounds using five different GC methods. Yeasts exert a strong influence on wine aroma throughout the whole aging period. Their effects extend beyond the well-known actions on yeast secondary metabolites, including the formation of little amounts of Strecker aldehydes or the formation of acids precursors of fruity esters, and on the enzymatic actions on the different grape aroma precursors. Additionally, yeasts influence wine aroma; first, by producing SO2 which reacts with ß-damascenone and increases Strecker aldehyde production in fermentation; second, by inducing the differential accumulation of Strecker aldehydes during anoxic aging; and third, by determining the stability of MOH, likely because of its reaction with vinylphenols or other yeast-related electrophiles

Impact of two yeast strains on tempranillo red wine aroma profiles throughout accelerated ageing

This study aimed at determining the changes induced by two S. cerevisiae strains, (IONYS wf™ and Lalvin ICV D254™) on the sensory and chemical aroma profiles of Tempranillo wine, after fermentation and after ageing. The 64 aroma molecules determined were grouped attending to sensory and chemical similarity into 17 aroma vectors. Sensory studies included a sorting task and a descriptive analysis by flash profile with a trained panel. Results revealed that, even if ageing is the dominant factor, the strain of yeast introduces significant and consistent differences, both in sensory and aroma vector profiles (11 out 17 affected). Wines made with D254 contained higher levels of ethyl esters, acetic acid, cinnamates and ethyl acetate and lower levels of linear fatty acids, ß-damascenone, acetaldehyde, higher alcohols and lactones than those made with IONYS. The first profile was related to black and fresh fruit notes, while the second to white and compote fruits. © 2021 International Viticulture and Enology Society-IVES

The Olfactory Threshold of Rotundone in Brandy is Ten-fold Higher than in Wine and does not Increase with the Complexity of the Matrix

Rotundone is the only known aroma compound imparting a peppery aroma to wine. Its presence hasrecently been documented in spirits, notably those aged in oak barrels. However, the sensory contributionof rotundone in such alcoholic beverages remains hard to predict, given their high ethanol level. The aimof this study was to estimate olfactory thresholds for rotundone in brandy using three different matrices.Rotundone concentrations in the unspiked samples were 50 ng/L for wine distillate and 135 ng/L for brandy,demonstrating for the first time the presence of rotundone in such spirits and a possible endogenous origin.The olfactory detection threshold was estimated at 103 ng/L in 40% (v/v) ethanol solution, while differencethresholds were 171 ng/L and 189 ng/L in fresh wine distillate and young French brandy, respectively, bothstandardised at 40% (v/v). These thresholds were 10-fold higher than in wines and did not significantlydiffer according to the complexity of the matrix. Our results, which are still preliminary and would deserveto be validated with a larger number of samples and using a higher number of panellists, open new fieldsof investigation for a deeper exploration of the concentration range of rotundone in brandies, particularlythose that underwent a longer ageing period in barrels

Towards Translational ImmunoPET/MR Imaging of Invasive Pulmonary Aspergillosis: The Humanised Monoclonal Antibody JF5 Detects Aspergillus Lung Infections In Vivo

This is the final published versionAvailable from Ivyspring International Publisher via the DOI in this recordInvasive pulmonary aspergillosis (IPA) is a life-threatening lung disease of hematological malignancy and bone marrow transplant patients caused by the ubiquitous environmental fungus Aspergillus fumigatus. Current diagnostic tests for the disease lack sensitivity as well as specificity, and culture of the fungus from invasive lung biopsy, considered the gold standard for IPA detection, is slow and often not possible in critically ill patients. In a previous study, we reported the development of a novel non-invasive procedure for IPA diagnosis based on antibody-guided positron emission tomography and magnetic resonance imaging (immunoPET/MRI) using a [64Cu]DOTA-labeled mouse monoclonal antibody (mAb), mJF5, specific to Aspergillus. To enable translation of the tracer to the clinical setting, we report here the development of a humanised version of the antibody (hJF5), and pre-clinical imaging of lung infection using a [64Cu]NODAGA-hJF5 tracer. The humanised antibody tracer shows a significant increase in in vivo biodistribution in A. fumigatus infected lungs compared to its radiolabeled murine counterpart [64Cu]NODAGA-mJF5. Using reverse genetics of the pathogen, we show that the antibody binds to the antigenic determinant 1,5-galactofuranose (Galf) present in a diagnostic mannoprotein antigen released by the pathogen during invasive growth in the lung. The absence of the epitope Galf in mammalian carbohydrates, coupled with the enhanced imaging capabilities of the hJF5 antibody, means that the [64Cu]NODAGA-hJF5 tracer developed here represents an ideal candidate for the diagnosis of IPA and translation to the clinical setting.This work was supported by the European Union Seventh Framework Programme FP7/2007-2013 under Grant 602820, the Deutsche Forschungsgemeinschaft (Grant WI3777/1-2 to SW), and the Werner Siemens Foundation. We thank Sven Krappman for use of the A. fumigatustdTomato strain, and acknowledge the Imaging Centre Essen (IMCES) for assistance with optical imaging of lungs

Germline MC1R status influences somatic mutation burden in melanoma

The major genetic determinants of cutaneous melanoma risk in the general population are disruptive variants (R alleles) in the melanocortin 1 receptor (MC1R) gene. These alleles are also linked to red hair, freckling, and sun sensitivity, all of which are known melanoma phenotypic risk factors. Here we report that in melanomas and for somatic C>T mutations, a signature linked to sun exposure, the expected single-nucleotide variant count associated with the presence of an R allele is estimated to be 42% (95% CI, 15-76%) higher than that among persons without an R allele. This figure is comparable to the expected mutational burden associated with an additional 21 years of age. We also find significant and similar enrichment of non-C>T mutation classes supporting a role for additional mutagenic processes in melanoma development in individuals carrying R alleles

Dispositif d'étude des décharges électriques

We present a device for the pulse regime study in electrical discharge in liquids and gases ; it allows us to measure the pulse charge Qi and to determine the elapsed time Δt between two successive pulses. We obtain the charge Qi by measuring the voltage variation ΔV across a known capacitor C in series with the test cell. The measured values are transfered and processed in a microcomputer. We thus obtain histograms of Qi and Δt, and then the mean pulse charge value, the mean pulse frequency and the corresponding standard deviations. Simultaneous seizure of 4 000 values of Qi and Δt leads us to research a correlation between the two quantities.Nous présentons un dispositif pour l'étude du régime impulsionnel de décharge dans les liquides et les gaz, à la fois pour la mesure de la charge Qi de chaque impulsion et pour la détermination de l'intervalle de temps Δt écoulé entre deux impulsions successives. La valeur de la charge est obtenue en mesurant la variation ΔV de la tension aux bornes d'une capacité C montée en série avec la cellule d'étude. Les intervalles de temps Δt sont mesurés par un ensemble comprenant une horloge et des compteurs. Les valeurs mesurées sont transférées et traitées dans un micro-ordinateur. On obtient les histogrammes de Qi et Δt, donc la charge moyenne des impulsions et leur fréquence moyenne ainsi que les écarts-types correspondants. La saisie simultanée de 4 000 valeurs de Qi et Δt nous permet de rechercher une corrélation entre les deux grandeurs

Spectral analysis of the light emitted by streamers in hydrocarbon liquids

International audienc

Mobility of non thermal electrons and ions in very high density and purified nitrogen corona discharge

WOS:000471052300021International audienceThe mobility of nonthermal electrons and ions have been determined in very high and purified nitrogen corona discharge. Corona discharge was generated by plasma generator system with point-to-plane electrodes geometry configuration. Charateristic I-V has been done by using stabilized DC high voltage generator high up to 20 kV. Graph current of saturation corona unipolar for variation voltage and the distance between electrodes is curved with the semi-parabolic equation. We used I-V characteristic to determine charge patricles mobilities. In this research high purified and slighly purified nitrogen gas. For negative corona, we found that the mobility of charged particles is greater than negative ions and smaller than thermal electron mobility. Particles engaging and moving in the corona with high purification the gas are nonthermal electrons, positive ions for positive corona. From the current-voltage characteristic, we can conclude that the regime of our discharge in very pure gases (N2) corresponds to the current regime limited by space charge. By analogy with what has been observed in a "discharge tube" this regime is similar to an abnormal glow discharge regime. We have seen previously that the variation with the density of the ionic mobility is in good agreement with the direct measurements by the time of flight metho

Light emission from corona discharge in SF

A spectroscopic investigation of corona discharges in SF6/N2 gas mixtures has been undertaken using an optical multichannel analyser (OMA). A point-to-plane geometry has been used with point radii varying from 3 to 10 μm. Spectra are measured for high pressures ranging from 0.2 MPa up to 1.4 MPa and for different concentrations of SF6 in the gas mixture. The spectra in the 200–850 nm spectral range are mainly made of molecular bands, which is indicative of a low temperature discharge. It has been noted that SF6 emits in the region of 420 nm to 510 nm in positive and negative polarities, although in negative polarity the emission is weaker. For SF6/N2 mixtures, the main source of light emission is from N2. The resultant spectra are used to evaluate the rotational Tr and vibrational Tv temperatures of excited N2, Tr being considered, due to the high pressure, to be equal to the kinetic temperature Tkin in the corona discharge. Tr and Tv are determined by comparing the experimental spectrum of the second positive system ($C^{3}\Pi_{u}\to B^{3}\Pi_{g})$ of N2 and the simulated one, which is obtained using a convolution method. As expected, the results show that the measured rotational temperature Tr increases steadily with the mean discharge current, while its increase with gas pressure is less pronounced. The values of Tr are higher for the positive corona discharge than the negative and also for mixtures having higher amounts of SF6. In all conditions, we found $T_{v}>T_{r}$ and Tv is less sensitive to the variation of the current