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This work studies the influence of the thickness of oak alternatives on the composition and quality of red wines. A red wine was aged in control conditions and also in contact with oak chips, and with thin and thick oak staves for 12 months. As expected, all the wines aged in contact with all the oak alternatives were enriched in total polyphenols and had a higher colour intensity. In addition, the contact with all the oak alternatives enriched the wine in furfural and total furans, vanilla and total aldehydes and ketones, eugenol and total volatile phenols, and in β-methyl-γ-octalactones. However, the thickness of the oak alternative seems to play an important role in the composition and quality of the wine. Specifically, the wines aged in contact with the two types of staves had a more intense colour than the wine aged with oak chips, as well as a higher total phenolic index and higher eugenol concentration. Moreover, the β-methyl-γ-octalactones concentration was higher in the wine supplemented with thick staves. Finally, the wines supplemented with the two types of staves had a higher intensity of the spicy attribute than the wine aged with oak chips. The wine supplemented with thick staves had a higher intensity of candy/pastry, toasted, smoked, complexity, aromatic intensity, sweetness, structure, and persistence. Finally, the panel preferred the wine aged with thick staves followed by, in descending order, the wines aged with thin staves, oak chips, and the control. [ABSTRACT FROM AUTHOR]

Sulfur dioxide is the most used additive today for preventing browning in grape musts and wines. However, since wine consumers are increasingly interested in healthier wines, the wine industry is keen to reduce its use. Some promising alternatives to sulfur dioxide have been proposed in recent years, including glutathione, both pure and in the form of inactivated yeasts, and Metschnikowia pulcherrima used as a bioprotective agent. Some information exists about the protective effect against oxidation of glutathione but there is very few about the use of bioprotection for that purpose. Supplementation with glutathione, regardless of the commercial form, reduced oxygen consumption and browning intensity when laccase was not present in the grape juice. Metschnikowia pulcherrima also reduced browning intensity in the absence of laccase but increased the total oxygen consumption. However, in the presence of laccase, glutathione and Metschnikowia pulcherrima were not effective enough to adequately prevent the grape juice from browning. Glutathione, both pure and in the form of inactivated yeasts, and Metschnikowia pulcherrima are interesting tools for protecting grape must against browning, and thus reducing the use of sulfur dioxide. [ABSTRACT FROM AUTHOR]

The aim of this research was to determine the effectiveness of the substitution of grape juice of grapes with different maturation degree and prefermentative hot maceration to obtain Pinot Noir and Tannat red wines with lower alcohol content and pH and higher color and phenolic compound concentrations. Immature grape juice was extracted of grapes harvested in veraison and kept at 4 °C until its use. In technological maturity, the grapes harvested were destemmed, crushed and distributed in 12 containers per cultivar. Six were controls while in the other six 3 L of the original grape juice were substituted by 3 L of unripe grape juice. Next, three containers from each experimental group were traditionally macerated, while the other three were submitted to a prefermentative hot maceration (one hour at 60–70 °C). All treatments performed a fermentative maceration of 7 days. Wines produced from substituted musts had lower alcohol content (14% off) and pH (9% off) and higher titratable acidity (48% more), but no other important changes in wine components were detected. Prefermentative hot maceration increased wine color intensity (50%), total phenolic compounds (66%), total anthocyanin (42%), proanthocyanidin (65%) and polysaccharide (95%) concentrations. The joint consideration of both techniques is an interesting tool to simultaneously mitigate the problems caused by climate change with respect to the maturity of the grape and improve the color of the wine and its concentration in polysaccharides and phenolic compounds. [ABSTRACT FROM AUTHOR]

The analytical and sensory analysis of wines aged in barrels of French and American oak with three different levels of toasting was performed to determine the relationship between the volatile substances released by oak wood and sensory appreciation by a trained panel. For that purpose, a discolored white wine of Macabeo and a red wine of Cabernet Sauvignon from 2012 vintage were aged for 12 months in new barrels. Similar wines from the following vintage were aged in the same barrels for knowing how the use of the barrels affects their capacity to release volatile substances and its organoleptic impact. A significant correlation was found between the appreciation of coconut and smoked/toasted notes by the panel and the theoretical sensory impact of β-methyl-γ-octalactone and volatile phenols, respectively, in two different wines aged in new oak barrels. Vanillin correlated significantly in only one of the wines tasted. The panelists generally preferred wines aged in medium-toasted new barrels for both oak species. In a triangle test, tasters could distinguish between wines aged in new American and French oak barrels when the toasting level was light or medium but not when it was heavy. They were also able to distinguish between wines aged in new and 1-year-used barrels. It can be concluded that the botanical origin of the oak, the toasting level of the staves and the number of times that the barrels have been used previously have a real impact on the volatile composition of the wine and in its sensory impact. [ABSTRACT FROM AUTHOR]

In a previous study, we reported that sequential inoculation of Torulaspora delbrueckii (strain TD291) and a specific strain of Saccharomyces cerevisiae during the first fermentation increased the protein concentration and improved the foaming properties of a base wine. Since effervescence and foam of sparkling wines are key quality factors, the interest of this practice for sparkling wine industry is obvious. In this paper, we study whether the foaming properties of the sparkling wines produced from the base wines obtained by sequential inoculation with these strains of T. delbrueckii and S. cerevisiae remain better than those of their controls produced from base wines fermented only with S. cerevisiae. The obtained results confirmed that sequential inoculation in the production of the base wine originated sparkling wines with significantly higher maximum heights of foam than conventional inoculation, probably because autolysis of the T. delbrueckii (strain TD291) cells in the base wine released higher amounts of proteins, especially of the low molecular weight fraction. [ABSTRACT FROM AUTHOR]

The use of non- Saccharomyces yeasts for the production of quality wine has become increasingly frequent in recent years. Several studies of the influence of Torulaspora delbrueckii and Metschnikowia pulcherrima on chemical composition have been reported, especially in aspects concerning aroma. The aim of this article was to study the influence of sequential inoculation of these non- Saccharomyces yeasts and Saccharomyces cerevisiae on the composition and quality of base wine for sparkling wine production. The results indicate that sequential inoculation with non- Saccharomyces yeasts may be an interesting tool for obtaining base wines with different characteristics. On the one hand, T. delbrueckii Biodiva™ strain increased glycerol concentration, reduced volatile acidity and exerted a positive effect on foaming properties improving foamability (Hm) and foam persistence (Hs). On the other hand, M. pulcherrima Flavia strain also increased foam persistence (Hs) and changed the aromatic profile, increasing smoky and flowery notes. [ABSTRACT FROM AUTHOR]

The rapid development of display technologies has raised interest in arrays of self-emitting, individually controlled light sources atthe microscale. Gallium nitride (GaN) micro-light-emitting diode (LED) technology meets this demand. However, the current technology is not suitable for the fabrication of arrays of submicron light sources that can be controlled individually. Our approach is based on nanoLED arrays that can directly address each array element and a self-pitch with dimensions below the wavelength of light. The design and fabrication processes are explained in detail and possess two geometries: a 6 × 6 array with 400 nm LEDs and a 2 × 32 line array with 200 nm LEDs. These nanoLEDs are developed as core elements of a novel on-chip super-resolution microscope. GaN technology, based on its physical properties, is an ideal platform for such nanoLEDs. Tiny lights enable molecular-scale imaging: Arrays of nanoscale light-emitting diodes (LEDs) offer an energy-efficient means for achieving microscopic imaging with resolution below the diffraction limit. Microscale LEDs are already poised to have a transformative impact on display technology, but it remains challenging to construct arrays of individually controllable LEDs at the nanometer scale. Daria Bezshlyakh of the Technische Universität Braunschweig in Germany and colleagues have developed a fabrication approach that enabled them to manufacture a compact super-resolution imaging system based on such arrays. Their device employs gallium nitride nano-LEDs that generate precisely structured patterns of illumination, which make it possible to image specimens at spatial resolutions smaller than the wavelength of light. Based on the performance and stability of this initial prototype, the authors conclude that similar devices could offer a promising platform for future molecular imaging applications. [ABSTRACT FROM AUTHOR]