Volatile and phenolic composition of a Chardonnay wine treated with antimicrobial plant extracts before malolactic fermentation

This work is licensed under a Creative Commons Attribution 3.0 License.Previous studies have proven the potential of antimicrobial plant extracts to delay malolactic fermentation (MLF) in red wines. With the final end of extending their applicability in oenology, the aim of this study was to investigate whether the addition of antimicrobial extracts (from eucalyptus leaves and almond skins) to white wines (i.e., Chardonnay wine), as a way to control MLF, would affect wine organoleptic properties, in particular those related to their volatile and phenolic composition. Although addition of both extracts led to statistically significant changes (p<0.05) in the concentration of several volatile and phenolic compounds, only few of them showed contents higher than their sensory thresholds, meaning that the changes observed in their concentration could slightly affect the final wine aroma and astringency. However, use of the extracts in the elaboration of white wines needs to be assessed in future experiments at winery scale, including wine sensorial analysis.This work has been funded by the Spanish Ministry for Science and Innovation (AGL2006-04514, AGL2009-13361-C02-00 and CSD2007-00063 Consolider Ingenio 2010 FUN-C-FOOD Projects), and the Comunidad de Madrid (ALIBIRD P2009/AGR-1469 Project). JJRB and AGR are the recipients of a fellowship from the JAE-Doc Program (CSIC) and DANONE Institute, respectively.Peer Reviewe

Reversed-phase high-performance liquid chromatography–fluorescence detection for the analysis of glutathione and its precursor γ-glutamyl cysteine in wines and model wines supplemented with oenological inactive dry yeast preparations

El pdf del artículo es la versión pre-print.A reversed-phase high-performance liquid chromatography-fluorescence detection methodology involving a pre-column derivatization procedure using 2,3-naphtalenedialdehyde in the presence of 5 and 0. 5 mM of dithiothreitol to determine total and reduced glutathione (GSH) and γ-glutamyl-cysteine (γ-glu-cys) in musts and wines has been set up and validated. The proposed method showed good linearity (R 2 >99% for reduced and total GSH, and R 2 >98% for γ-glu-cys) in synthetic wines, over a wide range of concentration (0-10 mg L -1). The limits of detection for reduced GSH in synthetic and real wines were almost the same (0. 13 and 0. 15 mg L -1, respectively) and slightly higher for γ-glu-cys (0. 24 mg L -1). The application of the method allowed knowing, for the first time, the amount of total and reduced GSH and γ-glu-cys released into synthetic wines by oenological preparations of commercial inactive dry yeast (IDY). In addition, the evolution of these three compounds during the winemaking and shelf life (0-9 months) of an industrially manufactured rosé wine supplemented with a GSH-enriched IDY showed that although GSH is effectively released from IDY, it is rapidly oxidized during alcoholic fermentation, contributing to the higher total GSH content determined in wines supplemented with GSH-enriched IDYs compared to control wines. © 2011 Springer Science+Business Media, LLC.IAO and JJRB acknowledge CAM and CSIC for their respective research grants. This work has been founded by PET2007-0134 project.Peer Reviewe

Chromatography-Fluorescence detection for the analysis 2 of glutathione and its precursor γ-glutamyl cysteine in 3 wines and model wines supplemented with oenological 4 inactive dry yeast preparations 5

Abstract 22 A Reverse Phase-High Performance Liquid Chromatography-Fluorescence detection 23 (RP-HPLC-FL) methodology involving a pre-column derivatization procedure using 24 2,3-naphtalenedialdehyde (NAD) in presence of 5 and 0.5 mM of dithiothreitol (DTT) 25 to determine total and reduced glutathione (GSH) and γ-glutamyl-cysteine (γ-glu-cys) in 26 musts and wines has been set up and validated. The proposed method showed good 27 linearity (R 2 &gt; 99 % for reduced and total GSH, and R 2 &gt; 98 % for γ-glu-cys) in 28 synthetic wines, over a wide range of concentration (0-10 mg L -1 ). The limits of 29 detection (LODs) for reduced GSH in synthetic and real wines were almost the same 30 (0.13 and 0.15 mg L -1 respectively) and slightly higher for γ-glu-cys (0.24 mg L -1 ). The 31 application of the method allowed knowing for the first time, the amount of total and 32 reduced GSH and γ-glu-cys released into synthetic wines by oenological preparations of 33 commercial inactive dry yeast (IDY). In addition, the evolution of these three 34 compounds during the winemaking and shelf-life (0-9 months) of an industrially 35 manufactured rosé wine supplemented with a GSH enriched IDY showed that although 36 GSH is effectively released from IDY, it is rapidly oxidized during alcoholic 37 fermentation, contributing to the higher total GSH content determined in wines 38 supplemented with GSH enriched IDYs compared to control wines

Characterization of the aroma-active, phenolic, and lipid profiles of the pistachio (pistacia vera l.) nut as affected by the single and double roasting process

The pistachio (Pistacia vera L.) nut is one of the most widely consumed edible nuts in the world. However, it is the roasting process that makes the pistachio commercially viable and valuable as it serves as the key step to improving the nut's hallmark sensory characteristics including flavor, color, and texture. Consequently, the present study explores the effects of the single-roasting and double-roasting process on the pistachio's chemical composition, specifically aroma-active compounds, polyphenols, and lipids. Results showed the total polyphenol content of increased with the roasting treatment; however, not all phenolic compounds demonstrated this behavior. With regard to the aroma and aroma-active compounds, the results indicated that roasting process results in the development of characteristics and pleasant aroma of pistachio samples due to the Maillard reaction. With regard to lipids, the pistachio roasting treatment reduced the concentration of CN38 diacylglycerides while increasing the amount of elaidic acid.The Scientific and Technological Research Council of TurkeyDepto. de Química AnalíticaFac. de Ciencias QuímicasTRUEpu

Recovery of aromatic aglycones from grape pomace winemaking by-products by using liquid-liquid and pressurized-liquid extraction

The potential of winemaking grape pomace by-products as a source of glycosidic aroma precursors that under enzymatic hydrolysis might release aroma compounds has been evaluated. Two different extraction methodologies, liquid-liquid and pressurized liquid extraction (LLE and PLE) were employed. Solid phase extraction (SPE)-GC-MS analysis of the hydrolyzed LLE glycosidic extract revealed 22 aroma compounds belonging to different chemical families (terpenes, C13 norisoprenoids, vanillines, etc.). Response surface methodology was employed to study the effect of the most significant PLE experimental variables (temperature and solvent composition) on the extraction of aromatic aglycones. The parameters of the model were estimated by multiple linear regressions. Most of the aroma compounds showed an adequate fit to the calculated model (18 compounds from 22 with R 2 > 0.8). The application of the optimized PLE conditions (50 % of ethanol in the hydroalcoholic solution) and 90 °C showed higher extraction yield of aglycones when comparing with the extraction yield obtained by LLE. © 2013 Springer Science+Business Media New York.This work has been funded by the CSIC INTRAMURAL Project 201070I036. CMG and JJRB thank the CSIC for their respective research contracts.Peer Reviewe

Bound aroma compounds of Gual and Listan blanco grape varieties and their influence in the elaborated wines

Listán blanco and Gual are two white grape varieties grown in Spain (Canary Islands) and Gual is also grown in Portugal (Madeira Island). Wine quality could be improved by exploiting the varietal characteristics present in grapes as aroma precursors. At the present time, the enologic potential of these varieties has not yet been studied. Aroma precursors in musts and skins, and free volatiles in wines were determined in samples of both varieties. Aroma precursors of must and skins were isolated by absorption on XAD-2 resin and the aglycone liberated by means of acid hydrolysis. Free volatiles from wines and from aroma precursors were extracted with dichloromethane and then analysed by gas chromatography-mass spectrometry (GC-MS). Among the aroma precursors analysed, only α-terpineol, linalool and linalool oxides, 4-allyl-2,6-dimethoxyphenol, 2-methoxy-4-vinylphenol, 4-hydroxybenzaldehyde, vanillin and benzyl alcohol showed contents in grapes comparable to the levels observed in wine volatile compoundsMinisterio de Educación y CienciaDepto. de Química AnalíticaFac. de Ciencias QuímicasTRUEpu

Effect of skin contact on bound aroma and free volatiles of Listán blanco wine

Listán blanco is the major grape variety of the Canary Islands. Aroma precursors in musts and free volatiles in wines and their variations due to the skin contact process (10 °C and 0-12 h of maceration) were determined in samples of the Listán blanco grape variety. Aroma precursors of must were isolated by absorption on XAD-2 resin and the aglycone liberated by means of acid hydrolysis. Free volatiles from wines and from aroma precursors were extracted with dichloromethane and then analysed by GC-MS. The results of two consecutive vintages show that only aroma precursors of some terpenes and phenols may affect the final wine aroma. However, the majority of the free compounds of the wines did not present differences in content that could be related to the skin contact process.Ministerio de Educacion y CienciaDepto. de Química AnalíticaFac. de Ciencias QuímicasTRUEpu

Nuevos avances en el conocimiento de los preparados de levaduras secas inactivas y sus aplicaciones industriales

Trabajo presentado al 34th World Congress of Vine and Wine celebrado en Oporto (Portugal) del 20 al 27 de junio de 2011.[ES]: Los preparados de levaduras secas inactivas (LSI) se emplean en la industria enológica para mejorar los procesos fermentativos y las características sensoriales de los vinos. Debido a la falta de estudios científicos sobre estos preparados de LSI, en este trabajo se presentan los resultados más relevantes obtenidos en nuestro laboratorio sobre el efecto de su adición en los vinos. Los estudios realizados se han centrado en el efecto de la adición de preparados de LSI en la liberación de compuestos solubles y en el aroma en medios vínicos, así como el efecto sobre las características sensoriales de vinos rosados elaborados a escala industrial. Por último, y debido a la importancia de la fermentación maloláctica en la elaboración de los vinos, se ha estudiado el papel de componentes específicos de los preparados de LSI en el crecimiento de las bacterias lácticas. En conjunto, los resultados presentados aportan información sobre el modo de acción de estos preparados, las principales diferencias entre ellos, y sus efectos en la calidad de los vinos elaborados.[EN]: Inactive Dry Yeast (IDY) preparations are usually used in the winemaking industry to enhance the fermentative processes and the sensory characteristics of wines. Due to the lack of scientific studies dealing with their effects in wine, this work presents an integrate information of the data obtained in our laboratory about commercial IDY preparations. These studies have mainly focused on the effect of the addition of IDYs in the release of soluble compounds and in the volatile compounds in model wines. Additionaly, it has been determine the effect of IDY addition on the sensory characteristics of industrially manufactured rosé wines. Finally, due to the importance of malolactic fermentation in wine making, the role of specific components of IDY on the growth of lactic acid bacteria has been determined. To sum up, the results presented in this work provide a better understanding of the action mode of IDY preparations, their main differences depending on the type of IDY, and the effect of their addition in wine quality.Peer Reviewe