Kinetic Studies on the Ability of Wines to Produce Hydrogen Sulfide (HS) and Methanethiol (MeSH).

Twelve wines have been stored in anoxia to monitor hydrogen sulfide (HS) and methanethiol (MeSH) emitted. Emissions were studied for 3 months at 75 °C, 10 months at 50 °C, and 18 months at 35 °C. HS emissions followed first-order kinetics with half-lives of 0.

Age-related characteristics in differentiated thyroid cancer: a 20-year single-center retrospective analysis in pediatric and adolescent patients.

Objective: To characterize a cohort of pediatric thyroid cancer patients, focusing on clinical features and outcomes stratified by age. Subjects and.

Methods: This retrospective analysis included 63 pediatric differentiated thyroid cancer patients treated at a Portuguese pediatric reference hospital over a period of 20 years.

The role of polyphenols in oxygen consumption and in the accumulation of acetaldehyde and Strecker aldehydes during wine oxidation.

This study explores the role of polyphenols in preventing oxidative deterioration of wine aroma. Wine models containing polyphenols extracted from grapes were fortified with delphinidin-3G (DELF) or catechin (CAT), and oxidized. DELF increased oxygen consumption rates (OCRs) and reduced the Strecker aldehydes (SAs) formation, while CAT decreased OCRs and increased SAs.

Central retinal vein occlusion after infliximab therapy in a young patient with ulcerative colitis.

Inflammatory bowel disease (IBD) is a chronic condition, characterized by recurrent inflammation of the gastrointestinal tract. While the primary focus of IBD management consists in controlling gastrointestinal symptoms, IBD also presents an increased risk of thromboembolic complications. Tumor necrosis factor alpha (TNF-α) inhibitors, namely infliximab, have become increasingly common in the management of multiple chronic inflammatory diseases such as IBD.

A two-run heart-cut multidimensional gas chromatography method using flame ionization and mass spectrometry for automated and robust determination of nearly complete wine aroma-volatile profiles.

A quantitative analytical method capable of determining the concentrations of 81 aroma-relevant wine volatiles covering nine orders of magnitude was developed and validated in this study. The method is based on stir bar sorptive extraction (SBSE) of 200 μL of wine diluted with 1.8 mL NaCl brine with pH 3.

Kinetics of aroma formation from grape-derived precursors: Temperature effects and predictive potential.

This study investigates the accumulation and degradation of aroma molecules released by acid hydrolysis of aroma precursors in winemaking grapes. A first-order kinetics model effectively interprets this accumulation, including subsequent degradation. Experimentation at three temperatures categorizes specific grape-derived aroma molecules into three stability-based groups: labile molecules from labile precursors, stable molecules from labile precursors, and stable molecules from stable precursors.

Optimization and Validation of a Method to Determine Enolones and Vanillin Derivatives in Wines-Occurrence in Spanish Red Wines and Mistelles.

Understanding the chemical nature of wine aroma demands accurate quantitative determinations of different odor-active compounds. Quantitative determinations of enolones (maltol, furaneol, homofuraneol, and sotolon) and vanillin derivatives (vanillin, methyl vanillate, ethyl vanillate, and acetovanillone) at low concentrations are complicated due to their high polarity. For this reason, this paper presents an improved and automated version for the accurate measure of these common trace wine polar compounds (enolones and vanillin derivatives).

Combination of SPE and fluorescent detection of AQC-derivatives for the determination at sub-mg/L levels of biogenic amines in dairy products.

Biogenic amines (BAs) are compounds generated by decarboxylation of their amino acid precursors. Their intake, even at low concentrations, can lead to several types of health problems in sensitive individuals. As they can be easily formed in fermented dairy products, their quantitative determination is very relevant.

Expanding the diversity of Chardonnay aroma through the metabolic interactions of cocultures.

Yeast co-inoculations in winemaking are often studied in the framework of modulating the aromatic profiles of wines. Our study aimed to investigate the impact of three cocultures and corresponding pure cultures of on the chemical composition and the sensory profile of Chardonnay wine. Coculture makes it possible to obtain completely new aromatic expressions that do not exist in the original pure cultures attributed to yeast interactions.

Accurate quantitative determination of the total amounts of Strecker aldehydes contained in wine. Assessment of their presence in table wines.

Strecker aldehydes (SAs) are key determinants of wine shelf-life and can be present in unoxidized wines in odorless forms, such as hydroxyalkylsulfonates, imines or acetals. A robust and accurate method for the determination of total forms of SAs, based on the classical derivatization with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) and in the selective solid phase extraction of derivatives has been optimized and validated. Matrix effects have been solved by the use of adequate internal standards and by large-enough equilibration times under anoxic conditions.

Factors That Affect the Accumulation of Strecker Aldehydes in Standardized Wines: The Importance of pH in Oxidation.

Strecker aldehydes (SA) can be formed in wine from the degradation of Strecker and, to a lesser degree, via the oxidation of higher alcohols. The objective of this article is to assess the magnitude of the differences introduced by wine compositional factors other than amino acids and Fe, in the accumulation of SA during oxidation. Eight red, two rosé and two white wines were oxidized.

Generation of intra- and interspecific Saccharomyces hybrids with improved oenological and aromatic properties.

Non-wine yeasts could enhance the aroma and organoleptic profile of wines. However, compared to wine strains, they have specific intolerances to winemaking conditions. To solve this problem, we generated intra- and interspecific hybrids using a non-GMO technique (rare-mating) in which non-wine strains of S.

Maturation of Moristel in Different Vineyards: Amino Acid and Aroma Composition of and Wines with Particular Emphasis in Strecker Aldehydes.

The aim of this article was to assess the influence of the harvest date on the composition of amino acids and derived aromatic compounds in grape- and wine of the Moristel variety, in different vineyards. Two vineyards were sampled in 2016 and another one in 2017. At each sampling point, grapes were collected, destemmed, crushed and divided into four aliquots.

Modulation of aroma and chemical composition of Albariño semi-synthetic wines by non-wine Saccharomyces yeasts and bottle aging.

Saccharomyces yeasts from different origins and species fermented in a semi-synthetic must containing aroma precursor of cv. Albariño and polyfunctional mercaptans precursors. The resulting wines were subjected to accelerate anoxic aging.

An Index for Wine Acetaldehyde Reactive Potential (ARP) and Some Derived Remarks about the Accumulation of Acetaldehyde during Wine Oxidation.

The amount of acetaldehyde accumulated during wine oxidation was very small, far less than expected. The existence of polyphenols specifically reactive to acetaldehyde was postuled. In order to assess the acetaldehyde reactive potential (ARP) of wines, different reactive conditions have been studied: acetaldehyde concentration, temperature and pH.

Effect of non-wine Saccharomyces yeasts and bottle aging on the release and generation of aromas in semi-synthetic Tempranillo wines.

Interest in the use of non-conventional yeasts in wine fermentation has been increased in the last years in the wine sector. The main objective of this manuscript was to explore the aromatic diversity produced by wild and non-wine strains of S. cerevisiae, S.

Can aldehyde accumulation rates of red wines undergoing oxidation be predicted in accelerated conditions? The controverted role of aldehyde-polyphenol reactivity.

Background: The accumulation of acetaldehyde and Strecker aldehydes during wine oxidation is detrimental to quality and often determines wine shelf-life. Knowing in advance the specific tendency of a wine to accumulate these compounds would help decision making during winemaking. An accelerated test based on a forced oxidation procedure at 45 °C (5 days) to measure aldehyde accumulation rates (AARs) is proposed and assessed by comparing results with those obtained by oxidation at 25 °C (36 days).

Role of Grape-Extractable Polyphenols in the Generation of Strecker Aldehydes and in the Instability of Polyfunctional Mercaptans during Model Wine Oxidation.

Polyphenolic fractions from Garnacha, Tempranillo, and Moristel grapes were reconstituted to form model wines of identical pH, ethanol, amino acid, metal, and varietal polyfunctional mercaptan (PFM) contents. Models were subjected to a forced oxidation procedure at 35 °C and to an equivalent treatment under strict anoxia. Polyphenolic profiles significantly determined oxygen consumption rates (5.

Oxidative and osmotolerant effects in Salvator merianae (Squamata: Teiidae) red blood cells during hibernation.

Hibernation is a natural condition of animals that lives in the temperate zone, although some tropical lizards also experience hibernation annually, such as the lizard native from South America, Salvator merianae, or "tegu" lizard. Even though physiological and metabolic characteristic associated with hibernation have been extensively studied, possible alterations in the red blood cells (RBC) integrity during this period remains unclear. Dehydration and fasting are natural consequences of hibernating for several months and it could be related to some cellular modifications.