Influencia de la madurez de la uva y de ciertas prácticas vitivinícolas sobre el color, los compuestos fenólicos y los polisacáridos del vino tinto

La madurez de la uva ejerce una gran influencia sobre la composición química del vino tinto, lo que a su vez condiciona severamente propiedades organolépticas como el color, la astringencia y el amargor. La enorme heterogeneidad de la uva, así como la variabilidad de los factores que condicionan el proceso de maduración y que pueden conducir a una madurez inadecuada, van en detrimento de la calidad de los vinos tintos de alta gama. Con el fin de paliar los efectos de dicha madurez inadecuada, se ha ensayado el potencial de ciertas técnicas vitivinícolas para incidir positivamente en la composición química del vino tinto. Las cuatro prácticas vitivinícolas testadas durante la elaboración de esta tesis doctoral (control del tiempo de maceración, selección de bayas en función de su tamaño, aclareo de frutos y desalcoholización parcial), se han revelado como herramientas eficaces para modular la composición química del vino tinto en compuestos fenólicos y polisacáridos, mejorando así atributos sensoriales tan importantes como el color, la astringencia y el amargor del vino

Chemical and Physical Implications of the Use of Alternative Vessels to Oak Barrels during the Production of White Wines

Recently, the use of alternative vessels to oak barrels during winemaking has become increasingly popular, but little is known about their impact on the chemical composition of the resulting wines. To address this issue, a Sauvignon Blanc wine was elaborated from the same grape juice by using cylindrical stainless-steel tanks, oval-shaped concrete vessels, oval-shaped polyethylene vessels, and clay jars in triplicate. Each vessel was used for alcoholic fermentation and the aging of wines over its own lees. Wines elaborated in concrete vessels showed the highest pH and the lowest titratable acidity, most likely related to the observed release of inorganic compounds from the concrete walls. Little effect of the vessels was seen on the wine color and phenolic composition. Wines elaborated in clay jars showed the highest turbidity and the highest content of soluble polysaccharides, while those made using cylindrical stainless-steel tanks showed the highest content of volatile compounds. Despite the observed differences, all of the vessels tested seem suitable for white wine production since every wine showed chemical features that corresponded with the quality standards of Sauvignon Blanc wines.España Universidad de Sevilla, VI Plan Propio de Investigación y Transferencia (Contract number USE-18644-Z

Influence of Maturity and Vineyard Location on Free and Bound Aroma Compounds of Grapes from the Pais Cultivar

Some of the volatile compounds present in grapes give wine is its unique and genuine characteristics. “Terroir” and berry maturity are considered to be the main influences on the expression of these characteristics. This work was undertaken to establish the specific characteristics that define Vitis vinifera cv. País, based on its aromatic profile and free and bound compounds (glycosides), and to assess the effects of location and maturity. Free and bound volatile compounds presented significant differences in the three locations studied. The total amount of free alcohols, acids and ketones depended on the location. During ripening, the amount of aroma precursors increased in all chemical groups in every location studied, and they were found mainly in the skins. With reference to free volatile compounds, it was found that cis-2- hexenol could be a good candidate to assess maturity, and that terpene content seemed to be strongly related to the vineyard location and cultivar conditions. Also, data analysis showed that the free aroma profile seemed to be influenced more by the maturity of the grapes and the bound aroma fraction more by the location

Different application dosages of a specific inactivated dry yeast (SIDY) : effect on the polysaccharides, phenolic and volatile contents and color of Sauvignon blanc wines

Aim: The aims of this study were to (i) study the effect of different application dosages of a commercial specific inactivated dry yeast (SIDY) on several compounds (polysaccharides, phenolic and volatile compounds) and attributes (color parameters) related to the quality of white wines, and (ii) acquire better knowledge about the use of different dosages of SIDY in white wines with the objective to improve their quality. Methods and results: Three different dosages were applied (10, 20 and 40 g hL-1). Treated wines were followed after a contact time period of two months and after a bottle aging period of three months. Total phenolic content, color intensity, CIELab coordinates, polysaccharides, low molecular weight phenolic compounds and volatile compounds were evaluated. Conclusions: Higher dosages of this SIDY resulted in a greater release of polysaccharides into the wine. In parallel, a positive effect on the reduction or prevention of wine oxidation was observed due to the interaction with certain phenolic compounds. The application of the highest dosage seems to lead to an adsorption or retention effect of the major identified volatile compounds. This effect seems to be more evident after the contact time period than after the bottle storage period. Significance and impact of the study: This study can contribute to improve our knowledge on how applying different dosages of SIDY affects the physical and chemical quality of white wines.CONICYT-PAI, República de Chile (concurso nacional inserción en el sector productivo, convocatoria 2014) No. 781403003FONDECYT (República de Chile) 11140275FONDECYT (República de Chile) 1140882FONDEQUIP (República de Chile) EQM- 13012

Chemical and Physical Implications of the Use of Alternative Vessels to Oak Barrels during the Production of White Wines

Recently, the use of alternative vessels to oak barrels during winemaking has become increasingly popular, but little is known about their impact on the chemical composition of the resulting wines. To address this issue, a Sauvignon Blanc wine was elaborated from the same grape juice by using cylindrical stainless-steel tanks, oval-shaped concrete vessels, oval-shaped polyethylene vessels, and clay jars in triplicate. Each vessel was used for alcoholic fermentation and the aging of wines over its own lees. Wines elaborated in concrete vessels showed the highest pH and the lowest titratable acidity, most likely related to the observed release of inorganic compounds from the concrete walls. Little effect of the vessels was seen on the wine color and phenolic composition. Wines elaborated in clay jars showed the highest turbidity and the highest content of soluble polysaccharides, while those made using cylindrical stainless-steel tanks showed the highest content of volatile compounds. Despite the observed differences, all of the vessels tested seem suitable for white wine production since every wine showed chemical features that corresponded with the quality standards of Sauvignon Blanc wines

Chemical and Physical Implications of the Use of Alternative Vessels to Oak Barrels during the Production of White Wines

Recently, the use of alternative vessels to oak barrels during winemaking has become increasingly popular, but little is known about their impact on the chemical composition of the resulting wines. To address this issue, a Sauvignon Blanc wine was elaborated from the same grape juice by using cylindrical stainless-steel tanks, oval-shaped concrete vessels, oval-shaped polyethylene vessels, and clay jars in triplicate. Each vessel was used for alcoholic fermentation and the aging of wines over its own lees. Wines elaborated in concrete vessels showed the highest pH and the lowest titratable acidity, most likely related to the observed release of inorganic compounds from the concrete walls. Little effect of the vessels was seen on the wine color and phenolic composition. Wines elaborated in clay jars showed the highest turbidity and the highest content of soluble polysaccharides, while those made using cylindrical stainless-steel tanks showed the highest content of volatile compounds. Despite the observed differences, all of the vessels tested seem suitable for white wine production since every wine showed chemical features that corresponded with the quality standards of Sauvignon Blanc wines

The diversity of effects of yeast derivatives during sparkling wine aging

Producción CientíficaThis study shows the monitoring of the physical, chemical and sensorial changes that occur in the sparkling wine along 18 months of aging due to different typology yeast-derived products; dry inactivated yeast from Saccharomyces (Saccharomyces cerevisiae) and non-Saccharomyces (Torulaspora delbrueckii) yeast strains, yeast autolysate, and yeast protein extract tested at two different doses. The addition of 5 g/hL yeast protein extract and inactivated yeast from T. delbrueckii helped to preserve esters in wines with 9 and 18 months of aging on lees. The addition of yeast autolysate achieved greater polysaccharide enrichment and gave rise to sparkling wines with the highest antioxidant activity. Effects on foaming properties were quite different depending on the aging time. Despite this, sparkling wines treated with 10 g/hL of yeast autolysate and Optimum White™ generally exhibited the highest foamability and foam stability. Further experiments with higher doses are needed to observe clear effects on sensory profile

Antarctic Soil Yeasts with Fermentative Capacity and Potential for the Wine Industry

Generalmente se emplean bajas temperaturas de fermentación para obtener vinos de alta calidad. Esto es especialmente interesante para la producción de vino blanco ya que evita la pérdida de compuestos volátiles y el aspecto pardeante; sin embargo, las levaduras fermentativas disponibles no suelen tolerar las bajas temperaturas. Por tanto, un lugar interesante para encontrar nuevas levaduras con criotolerancia es el continente antártico. De muestras de suelo recolectadas en la Antártida se aislaron 125 levaduras, de las cuales 25 exhibieron actividad fermentativa a 10 °C. Después de un ensayo de huellas dactilares, clasificamos a los candidatos en nueve isotipos y secuenciamos regiones espaciadoras transcritas internas para su identificación. Estas levaduras fueron identificadas como parte del género Mrakia . Las pruebas de tolerancia al azúcar y al alcohol mostraron que algunas de estas levaduras del suelo antártico podían crecer hasta un 9% de alcohol y se alcanzaba un 25% de azúcar; sin embargo, exhibieron períodos de latencia más largos en comparación con el control Saccharomyces cerevisiae . La temperatura de crecimiento óptima para las levaduras antárticas aisladas fue entre 10 °C y 15 °C. Un análisis exhaustivo de los resultados obtenidos mostró que los aislados 10M3-1, 4M3-6 y 4B1-35 podrían ser buenos candidatos para fines de fermentación debido a su alcohol, tolerancia al azúcar y características de crecimiento. Nuestros resultados demuestran que es posible aislar levaduras fermentativas del suelo antártico con características prometedoras para su uso potencial en la industria vitivinícola.Instituto Antártico Chileno (INACH). “XXIV Concurso Nacional de Proyectos de Investigación Científica y Tecnológica Antártica 2018” RG_24-18Dirección Investigación—VRID, Universidad Autónoma de Chile - DIUA 260-2023Agencia Nacional de Investigación y Desarrollo (ANID) del Ministerio de Ciencia, Tecnología, Conocimiento e Innovación. Gobierno de Chile - VIU23P002

Chemical, Physical, and Sensory Effects of the Use of Bentonite at Different Stages of the Production of Traditional Sparkling Wines

The addition of bentonite to wine to eliminate unstable haze-forming proteins and as a riddling adjuvant in the remuage is not selective, and other important molecules are lost in this process. The moment of the addition of bentonite is a key factor. Volatile profile (SPME-GC-MS), foam characteristics (Mosalux method), and sensory analyses were performed to study the effect of the distribution of the dosage of bentonite for stabilization of the wine among the addition on the base wine before the tirage (50%, 75%, and 100% bentonite dosage) and during the tirage (addition of the remaining dosage for each case). Results showed that the addition of 50% of the bentonite to the base wine (before the tirage) resulted in sparkling wines with the lowest quantity of volatile compounds, mainly esters and norisoprenoids. No significant differences were found among the sparkling wines after 9 months of aging in relation to foam properties measured by Mosalux, although higher foamability and crown’s persistence were perceived in the sparkling wines with the addition of 75% and 100% of the bentonite dosage in sensory trials. The results of this study suggested that the amount of bentonite added as a fining agent in the tirage had greater effects than during the addition of this agent in the base wine