Polyphenol Contents of Skin-Contact Fermented White Wines

Skin-contact fermented white wines, the so-called orange or qvevri wines, have been gaining international attention from winemakers, importers, sommeliers, consumers, and journalists over the last 10 years. Sommeliers are now regularly pairing orange wines with fine cuisine. This new culinary trend is part of a general move by the consumer wishing to respect the existence of traditions and innovation, combined with a growing interest in environmental awareness and healthy options. Orange wines are made from white grapes using ancient Georgian techniques. The essence of this method is the long skin-contact fermentation in amphorae without any chemicals or specific yeast. In our work, the polyphenol content of orange wines, in particular total polyphenol and catechin content, as well as colour intensity were measured to ensure safe winemaking technology without oxidized components

Interactions between large molecules pose a puzzle for reference quantum mechanical methods

Quantum-mechanical methods are used for understanding molecular interactions throughout the natural sciences. Quantum diffusion Monte Carlo (DMC) and coupled cluster with single, double, and perturbative triple excitations [CCSD(T)] are state-of-the-art trusted wavefunction methods that have been shown to yield accurate interaction energies for small organic molecules. These methods provide valuable reference information for widely-used semi-empirical and machine learning potentials, especially where experimental information is scarce. However, agreement for systems beyond small molecules is a crucial remaining milestone for cementing the benchmark accuracy of these methods. We show that CCSD(T) and DMC interaction energies are not consistent for a set of polarizable supramolecules. Whilst there is agreement for some of the complexes, in a few key systems disagreements of up to 8 kcal mol−1 remain. These findings thus indicate that more caution is required when aiming at reproducible non-covalent interactions between extended molecules

Enhancing Phenolic Maturity of Syrah with the Application of a New Foliar Spray

Climate change is inducing earlier grape ripening, especially in warm vintages. This phenomenon isresulting in unbalanced wines an alcohol concentration that is too high and titratable acidity that is low,along with a high pH level without the desired level of phenolic maturity. Final wine quality notably dependson the phenolic composition of the grapes and the extractability of these compounds. This research wasdesigned to test a new foliar spray, called LalVigne® MATURE, for its capacity to create a balance betweensugar development and phenolic maturity. It is a formulation of 100% natural, inactivated wine yeastderivatives. This foliar spray was tested on Syrah vines in two vintages (2012 and 2013) in a cool-climatewine region (Eger, Hungary). The spray acted as an elicitor, stimulating the synthesis of several secondarymetabolites. The changes in anthocyanin extractability and texture characteristics of the grape berrieswere followed during ripening. Experimental wines were made at three separate harvest times in eachvintage. Standard analytical parameters were evaluated for grapes and wines, as well as for resveratrol.Grapes from the treated vines had thicker skins than the controls at all sampling dates in both vintages.The phenolic potential (especially anthocyanin concentration and extractability) of the foliar spray-treatedgrapes was greatly improved. Our experiment showed that phenolic ripening can be enhanced using thefoliar spray, and that its application was useful in different vintages

The effect of yeast on the anthocyanin characteristics of fermented model solutions

The sensory quality of red wines is basically determined by the colour, which depends on the amount and on the evolution of anthocyanins and other phenolic compounds extracting from the berries into the wine during wine-making. The anthocyanin-monomers are responsible for the development of the red colour, and their acylated derivatives provide stability for the colour of the wines. The anthocyanin profile of wines is affected by several factors: the grape variety, the conditions during wine-making, and also the yeast culture used for the fermentation. In our experiments a self-compiled model solution was fermented by spontaneous fermentation, as well as by four commercial yeasts under laboratory conditions. After fermentation total polyphenolics, anthocyanins, anthocyanin monomer profile, colour intensity, hue, and the ratio of polymeric anthocyanins were studied. Our results show that the spontaneous yeast fermentation resulted in a higher anthocyanin concentration in the fermented model solution, but the commercial yeast strains provided a more advantageous colour characteristic compared to the spontaneous fermentation. After the spontaneous fermentation less sediment was left than in the commercial yeast fermented samples

Compatibilidad de variedades de cerezo húngaras sobre Adara y otros patrones Prunus

3 Págs. Contribución de los autores originalmente presentada, como comunicación,en el XIII Congreso Nacional de Ciencias Hortícolas (SECH 2012): “Convergencia de las Tecnologías Hortofrutícolas” (Almería, abril 2012)El presente trabajo tiene como objetivo determinar el grado de compatibilidad que presenta el ciruelo Adara y otros patrones Prunus para su utilización con variedades de cerezo húngaras. Entre las variedades estudiadas figuran: ‘Aida’, ‘Alex’, ‘Carmen’, ‘Kavics’, ‘Krupnoplodnaja’, ‘Rita’, ‘Sandor’ y ‘Vera’. El estudio se desarrolla sobre árboles injertados en viveros experimentales establecidos en la Estación Experimental de Aula Dei y fincas privadas comerciales. Para determinar los posibles casos de incompatibilidad del tipo ‘traslocada’ se realizaron observaciones visuales en campo durante el primer período vegetativo del árbol. Hasta la fecha no se han observado síntomas de incompatibilidad ‘traslocada’ para las combinaciones evaluadas. El diagnóstico de la incompatibilidad ‘localizada’ se realizará en años sucesivos mediante el examen macroscópico de las uniones de injerto y la determinación del grado de discontinuidad encontrado en corteza y madera.Este trabajo ha sido financiado por la acción integrada hispano-húngara del Ministerio de Ciencia e Innovación español (MICINN) (proyecto HH2008-0012) y de la ‘National Innovation Office’ húngara (NIH) (proyecto ES-27/2008), así como por el proyecto AGL-2008-00283 cofinanciado por FEDER, y el Gobierno de Aragón (A44).Peer reviewe

Effects of aging in oak barrels on the trans-resveratrol and anthocyanin concentration of red wines from Hungary

Polyphenol compounds in grapes and wines are of paramount importance: they have a key role in determining wine quality, and also the beneficial health effects of moderate red wine consumption are well-known. The polyphenol concentration of wines is determined mostly by: a) their concentration in the grapes and b) the production technology, particularly the time and type of aging. Our goal was to determine the trans-resveratrol and anthocyanin contents of Hungarian red wines under different manufacturing conditions, by monitoring the 24-month aging process – using barrique and oak barrels - with semi-annual sampling, without considering vintage. We have chosen to determine polyphenol components that could originate from either the grapes, or be produced during the wooden barrel aging. Both the aging time and the wine variety had non-negligible effects on the changes in the concentrations of the studied components, whereas the wooden barrel type had not

The effect of fine lees as a reducing agent in sur lie wines, aged with various sulphur dioxide concentrations

During the ageing in barrels, the contact with the fine lees triggers several processes in wine. Lees has a reductive effect by absorbing dissolved oxygen and reducing the amount, which will remain in the wine. At present, minimizing the addition of sulphur dioxide is the trend in all viticultural areas. In this study, the effect of various sulphur dioxide levels was monitored in presence of the lees to determine which dose is appropriate to provide the protection of susceptible white wine against oxidation. Without SO2 protection, the rH and redox potential changed slightly, so the level of dissolved oxygen seemed to be controlled during the ageing period by the lees, though the antioxidant effect of lees in itself was not appropriate to protect the polyphenol content from chemical oxidation, which led to considerable browning. With the addition of a lower amount of SO2 — 40 mg l2, the lees is already able to protect the white wine samples in all aspects

Performance of ab initio and density functional methods for conformational equilibria of CnH2n+2 alkane isomers (n=2-8)

Conformational energies of n-butane, n-pentane, and n-hexane have been calculated at the CCSD(T) level and at or near the basis set limit. Post-CCSD(T) contribution were considered and found to be unimportant. The data thus obtained were used to assess the performance of a variety of density functional methods. Double-hybrid functionals like B2GP-PLYP and B2K-PLYP, especially with a small Grimme-type empirical dispersion correction, are capable of rendering conformational energies of CCSD(T) quality. These were then used as a `secondary standard' for a larger sample of alkanes, including isopentane and the branched hexanes as well as key isomers of heptane and octane. Popular DFT functionals like B3LYP, B3PW91, BLYP, PBE, and PBE0 tend to overestimate conformer energies without dispersion correction, while the M06 family severely underestimates GG interaction energies. Grimme-type dispersion corrections for these overcorrect and lead to qualitatively wrong conformer orderings. All of these functionals also exhibit deficiencies in the conformer geometries, particularly the backbone torsion angles. The PW6B95 and, to a lesser extent, BMK functionals are relatively free of these deficiencies. Performance of these methods is further investigated to derive conformer ensemble corrections to the enthalpy function, $H_{298}-H_0$, and the Gibbs energy function, ${\rm gef}(T)\equiv - [G(T)-H_0]/T$, of these alkanes. While $H_{298}-H_0$ is only moderately sensitive to the level of theory, ${\rm gef}(T)$ exhibits more pronounced sensitivity. Once again, double hybrids acquit themselves very well.Comment: J. Phys. Chem. A, revised [Walter Thiel festschrift