Relationship between foaming properties and polysaccharide composition of sparkling wines

Póster presentado en las XI Carbohydrate Symposium (XI Jornadas de Carbohidratos), celebradas en Logroño del 28 al 30 de mayo de 2014.Peer Reviewe

Polysaccharide content of extracts obtained from unfermented skins from red varieties

Grape pomace is one of the main by-products generated by wine industry and contains several bioactive compounds such as polysaccharides. They are contained in the cell walls of the grape skins. The variety can be an important factor influencing the polysaccharide content of grapes. Actually, there is great interest in the revaluation of by-products and their incorporation into the production process. Therefore, the aim of this work was to evaluate the polysaccharide content of different extracts obtained from unfermented pomaces of different red grape varieties from Castilla y León. Eight different grape varieties were studied. The polysaccharides from grape pomace was obtained following a flash extraction process and the total polysaccharide content and the molecular weight distribution were estimated by High-Performance Size-Exclusion Chromatography with a Refractive Index Detector. Statistically significant differences were found in the content of total polysaccharides by grape variety varying between 112 and 200 mg/g. Only high and low molecular weight polysaccharide fractions were detected. All varietal extracts presented higher percentage of low molecular weight polysaccharides (50.8-64.3%) than of high molecular weight (35.7-49.2%)

Effect of grape maturity on the carbohydrate composition of red sparkling wines

Póster presentado en el 10th International Symposium of Enology (OENO 2015), celebrado en Burdeos del 19 de junio al 1 de julio de 2015.The authors thank the INIA for financing this study through the projects RTA2012-00092-C02-01 (with FEDER funds). Leticia Martínez thanks the Consejería de Educación del Gobierno de La Rioja for the FPI-CAR grant.Peer Reviewe

Influence of polysaccharide commercial product addition on volatile composition of white sparkling wines

Póster presentado en las XI Carbohydrate Symposium (XI Jornadas de Carbohidratos), celebradas en Logroño del 28 al 30 de mayo de 2014.Peer Reviewe

Kinetics of oxygen consumption, a key factor in the changes of young wines composition

Producción CientíficaThe oxygen that a wine receives during the winemaking process defines its properties. The aim of this work was to evaluate the oxygen consumption capacity of wines and its influence on the modification of their composition. This preliminary work evaluated the changes after 3 months in the chemical composition of twenty-seven Spanish commercial red, white and rosé wines after their air saturation and oxidation process at 35 °C for 7 days. All the wines studied were high oxygen consumers, while the white and rosé wines showed greater variability according to their chemical composition. Wines that consumed a lot of oxygen did so quickly or slowly, while wines that consumed little oxygen did so slowly. All the wines showed a significant decrease in ethyl esters of straight-chain fatty acids (50–58%), ethyl esters of branched-chain fatty acids (48–56%) and alcohol acetates (34–65%) content, and a significant increase in Strecker aldehydes (24%) because of oxygen consumption. This paper presents a preliminary approach to determine the oxidation tendency of different wines showing the importance of controlling the winemaking processes that can increase oxygen availability and of establishing the minimum appropriate level of free sulfur dioxide.Ministerio de Asuntos Económicos y Transformación Digital (AGL2017-87373-C3-2-R

Comparative study of red grape mustnanofiltration: Laboratory and pilot plant scales

Producción CientíficaA consequence of global warming is the early ripening of grapes which promotes, among others, a higher fermentablesugar (glucose and fructose) content. This leads to wines with an alcoholic degree higher than desired.In this work, the main differences between red grape must nanofiltration at laboratory and pilot plant scale werestudied in order to perform the scale-up of a nanofiltration process to reduce the sugar content. For this, previousresults of the nanofiltration of commercial red must using the SR3 membrane in a flat sheet crossflow module werecompared with those obtained for the filtration of natural red must using the same membrane in a spiral woundmodule at two different applied pressures.The aim of this publication is to analyze the main differences between red grape must nanofiltration at laboratoryand at pilot plant scale.Results: showed that the flow destabilization and eddy promotion caused by spacers in the spiral wound modulemitigate the rate at which the cake thickens and compacts on the membrane surface. This causes a less sharp fluxdecrease, less variable sugars rejection and osmotic pressure difference. Moreover, higher applied pressure promotesa higher membrane fouling and osmotic pressure that worsen the flux decayJunta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA248U13

Uso de diferentes técnicas enológicas para la preparación de vinos base tintos: Incidencia en la composición volátil

Póster presentado en el 37th World Congress of Vine and Wine, celebrado en Mendoza (Argentina) del 9 al 14 de noviembre de 2014.[EN] In recent years, the market of natural sparkling wines is growing quite fast in Spain due to the increase of both national consumption and export volume. Most of the sparkling wines elaborated in our country are white and rosé ones, being the production of red sparkling wines practically non-existent. However, these wines are elaborated in other countries like Australia, South-Africa, Argentina, Italy or Portugal, with a great acceptance by consumers. One of the initial problems is to obtain suitable base wines that should have moderate alcohol content, good colour intensity and good mouthfeel. Therefore, different winemaking techniques have been studied that allow to obtain suitable base wines for the elaboration of natural red sparkling wines, focused in this work on the volatile composition. Grapes from Tempranillo variety were harvested in two maturity moments: prematurity grapes (PM) with alcohol degree and acidity suitable to elaborate a sparkling wine, but that they do not have the adequate phenolic maturity, and grapes at their optimum degree of maturity (M). Then, two winemaking techniques were carried out for each type of grapes: pre-fermentative cold maceration with dry ice (PM-DI) and rack and return with partial removal of seeds (“delestage”) (PM-D) with the prematurity grapes; and removal of part of the sugar present in must (M-SR) and partial dealcoholisation of wine (M-AR) with the maturity grapes. In both moments, a control wine was also elaborated. All the elaborations were carried out in duplicate. The volatile compounds were analysed by gas chromatography coupled to a mass detector, after a previous liquid-liquid extraction. The analyses were carried out in triplicate. The wines obtained with prematurity grapes had an alcohol degree of 11 º, while those obtained with maturity grapes had 12.5º. Therefore, the M-SR y M-AR wines were reduced their a lcohol degree in 1.5º. In general, the wines obtained with maturity grapes showed the highest levels of ethyl esters, mainly ethyl hexanoate, ethyl octanoate and ethyl cinnamate, and of vanillin derivatives, with the exception of M-AR wine that showed a lower ethyl esters of straight-chain fatty acids. On the contrary, the wines elaborated with the prematurity grapes showed the highest concentrations of alcohol acetates and C6 alcohols, 1-hexanol and cis-3-hexenol, compounds responsible of herbaceous aromas. Taking into account these results, the base wines obtained with the maturity grapes could be more suitable than those obtained with prematurity ones for sparkling wine elaboration, although it should be considered other aspects.[ES] En los últimos años, el sector de los vinos espumosos naturales es uno de los que más está creciendo en España, tanto en consumo nacional como en volumen de exportaciones. La mayor parte de los vinos espumosos que se elaboran en nuestro país son blancos y rosados, siendo la elaboración de vinos espumosos tintos prácticamente inexistente. Sin embargo sí se elaboran en otros países como Australia, Sudáfrica, Argentina, Italia o Portugal, con una gran aceptación por parte de los consumidores. Uno de los problemas iniciales que se plantea es la obtención de un vino base adecuado, con una graduación alcohólica moderada, una buena intensidad de color, y una buena estructura en boca. Por ello, se ha estudiado el efecto de diferentes técnicas enológicas que permitan obtener vinos base idóneos para la elaboración de vinos espumosos tintos naturales, centrándose en este trabajo en la modificación de la composición volátil. Se vendimiaron uvas de la variedad Tempranillo en dos momentos de maduració n: uvas pre-maduras (PM) con valores de grado alcohólico y acidez adecuados para elaborar un vino espumoso, pero que todavía no tienen la madurez fenólica deseada, y uvas en su momento óptimo de maduración (M). Posteriormente, se llevaron a cabo dos técnicas enológicas con cada tipo de uva: maceración pre-fermentativa en frío con hielo seco (PM-DI) y “delestage” con una eliminación parcial de las semillas (PM-D) con las uvas pre-maduras; y reducción de azúcares en el mosto (M-SR) y desalcoholización parcial del vino (M-AR) con las uvas maduras. En ambos momentos de vendimia se elaboró también un vino testigo. Todas las elaboraciones se realizaron por duplicado.Los compuestos volátiles se han analizado por cromatografía de gases-masas, previa extracción líquido-líquido. Los análisis se llevaron a cabo por triplicado. Los vinos obtenidos con uva pre-madura presentaron un grado alcohólico de 11º, mientras que en los elaborados con uva madura fue de 12,5º. Por ello, se redujo el contenido en alcohol aproximadam ente en 1,5º a los vinos M-SR y M-AR. En general, los vinos elaborados con uva madura presentaron mayores concentraciones de ésteres etílicos, principalmente de hexanoato de etilo, octanoato de etilo y cinamato de etilo, y de los derivados de vainillina, a excepción del M-AR que presentó menores concentraciones de los ésteres etílicos lineales. Por el contrario, los vinos elaborados con uva pre-madura presentaron mayores concentraciones de acetatos de alcoholes, y de alcoholes C6, principalmente de 1-hexanol y cis-3-hexenol, compuestos responsables de los aromas herbáceos. Teniendo en cuenta estos resultados, los vinos base obtenidos con uvas maduras podrían ser más adecuados para la elaboración de vinos espumosos, aunque habría que considerar otros aspectos.The authors wish to thank the INIA for financing this study through the project RTA2012-092-C02.Peer Reviewe