Simultaneous Determination of Ethanol and Methanol in Wines Using FTIR and PLS Regression.

Accurate quantification of ethanol and methanol is essential for regulatory compliance and product quality assurance. Fourier Transform Infrared Spectroscopy (FTIR) offers rapid, non-destructive analysis with minimal sample preparation, making it a promising tool for wine analysis. In this exploratory study, the use of FTIR and PLS regression for the simultaneous quantification of ethanol and methanol in wine samples of 11 different Portuguese mono-varietal wines and different vintages deriving from the same winery in Lisbon was investigated.

First Approach to the Aroma Characterization of Monovarietal Red Wines Produced from Varieties Better Adapted to Abiotic Stresses.

Adaptation strategies in the wine sector consist of the use of cultural techniques to limit damages caused by climate change, using, among other resources, varieties better adapted to the scenarios of abiotic stress exacerbation, namely water and thermal stress, as well as those more tolerant to heatwaves. With the intention to determine the aromatic characterization of ten monovarietal wines produced from cultivars with high productive performance in a global warming scenario ('Petit Verdot', 'Marselan', 'Merlot', 'Touriga Franca', 'Syrah', 'Vinhão', 'Bobal', 'Preto Martinho', 'Trincadeira', and 'Alicante Bouschet'), grown in Esporão vineyard (Alentejo, Portugal) and submitted to deficit irrigation (Ks ± 0.5), their aromatic character has been analyzed.

Use of Oak and Cherry Wood Chips during Alcoholic Fermentation and the Maturation Process of Rosé Wines: Impact on Phenolic Composition and Sensory Profile.

There is a lack of knowledge about the use of different wood species on rosé wine production. Thus, this work focused on the impact of the addition of wood chips from oak and cherry trees during the alcoholic fermentation and maturation process on rosé wine characteristics. Therefore, phenolic composition and sensory characteristics were monitored during the rosé wines' production.

Grape Flavonoid Evolution and Composition Under Altered Light and Temperature Conditions in Cabernet Sauvignon (Vitis vinifera L.).

The evolution of flavonoids under altered temperature and light conditions in the fruit zone was followed in Cabernet Sauvignon ( L.) grapes during ripening. The study was conducted over two consecutive seasons in 2010/2011 and 2011/2012 comprising two main treatments in which the light quantity was manipulated in the bunch zone: (1) standard (STD) with no lateral shoot or leaf removal and (2) leaf removal west (LRW) treatment with leaf removal on the western side of the bunch zone.

Climate effects on physicochemical composition of Syrah grapes at low and high altitude sites from tropical grown regions of Brazil.

The major areas of the world where viticulture is practiced enjoy temperate or cool temperature climates. When wine grapes are grown in tropical regions, edaphoclimatic factors result in distinct grape quality attributes, and production techniques also require significant adjustment. The objective of this study was to characterize the chemical compositions, in particular of phenolic compounds, of Syrah grapes grown in two location in northeast Brazil - these are also at widely different altitudes.

Chemical characteristics of grapes cv. Syrah (Vitis vinifera L.) grown in the tropical semiarid region of Brazil (Pernambuco state): influence of rootstock and harvest season.

Background: Obtaining two or more successive annual vintages from the same vineyard is characteristic of regions with a tropical climate, such as the Submédio of the São Francisco Valley, Brazil. The present study aimed to characterize the chemical composition of grapes in four production cycles (i.e.

Acacia, cherry and oak wood chips used for a short aging period of rosé wines: effects on general phenolic parameters, volatile composition and sensory profile.

Background: There is a restricted knowledge about the potential impact of the use of different wood chip species on the rosé wine aging process. Thus, the aim of this work was to evaluate the general phenolic parameters, aroma composition and sensory profile of rosé wines during a short maturation (20 aging days) in contact with wood chips from oak, acacia and cherry. In addition, the different wood chips were added to a rosé wine without a previous clarification process (unfined wine) and to a rosé wine submitted to a clarification process (fined wine).

Effect of on the Formation of Polymeric Pigments during Sequential Fermentation with and .

Anthocyanins in red grape musts may evolve during the winemaking process and wine aging for several different reasons; colour stability and evolution is a complex process that may depend on grape variety, winemaking technology, fermentative yeast selection, co-pigmentation phenomena and polymerization. The condensation of flavanols with anthocyanins may occur either with the flavylium ion or with the hemiacetal formation in order to produce oligomers and polymers. The kinetics of the reaction are enhanced by the presence of metabolic acetaldehyde, promoting the formation of pyranoanthocyanin-type dimers or flavanol-ethyl-anthocyanin structures.

Effect of Wood Aging on Wine Mineral Composition and Sr/Sr Isotopic Ratio.

The evolution of mineral composition and wine strontium isotopic ratio Sr/Sr (Sr IR) during wood aging were investigated. A red wine was aged in stainless steel tanks with French oak staves (Quercus sessiliflora Salisb.), with three industrial scale replicates.

Kinetics of odorant compounds in wine brandies aged in different systems.

The odorants compounds of aged wine brandies comprise compounds deriving from the wood, from the distillate and from the reactions that occur inside the barrel. The aim of this work was to study the kinetics of the odorant compounds of a wine brandy during two years of ageing in two ageing systems. The odorant compounds in the analysed brandies changed significantly over the time, but with different evolution patterns.

Comparative study of the phenolic composition of seeds and skins from Carménère and Cabernet Sauvignon grape varieties (Vitis vinifera L.) during ripening.

The phenolic composition of skins and seeds from Vitis vinifera L. cv. Carménère and Cabernet Sauvignon grapes during ripening was evaluated by high-performance liquid chromatography-diode array detection and spectrophotometric analysis.

Chemical characterization and antioxidant activities of oligomeric and polymeric procyanidin fractions from grape seeds.

Two procyanidin fractions, namely oligomers and polymers isolated from grape seed methanolic extract were characterized. Phenolic composition and procyanidin purity of these fractions were determined by normal-phase and reverse-phase HPLC, thioacidolysis-HPLC, ESI-MS analyses, formaldehyde-HCl precipitation and elemental analysis. Antioxidant activities of these fractions and other well-known antioxidants were measured using xanthine-xanthine oxidase system for generating superoxide radical ({O2(-)}), the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical method and the Fenton system for generating hydroxyl radical (HO).

Monomeric, oligomeric, and polymeric flavan-3-ol composition of wines and grapes from Vitis vinifera L. Cv. Graciano, Tempranillo, and Cabernet Sauvignon.

The monomeric, oligomeric, and polymeric flavan-3-ol composition of wines, grape seeds, and skins from Vitis vinifera L. cv. Graciano, Tempranillo, and Cabernet Sauvignon has been studied using (1) fractionation by polyamide column chromatography followed by HPLC/ESI-MS analysis, (2) fractionation on C(18) Sep-Pak cartridges followed by reaction with vanillin and acid-catalyzed degradation in the presence of toluene-alpha-thiol (thiolysis).

Effects of cultivar and processing method on the contents of catechins and procyanidins in grape juice.

The aim of the presented work was to study the effect of pressing method, pasteurization, cultivar, and vintage on the content of (+)-catechin, (-)-epicatechin, and nine procyanidins in grape juice. The results showed that the concentration of these flavan-3-ols in the juice was influenced, in decreasing order of importance, by pressing method, cultivar, pasteurization, and vintage. Cold pressing without maceration was the least and hot pressing after maceration at 60 degrees C for 60 min the most effective method for extracting the flavan-3-ols.