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Barbastro, Spain

Hernandez-Orte P.,University of Zaragoza | Concejero B.,University of Zaragoza | Astrain J.,Bodega Pirineos | Lacau B.,Bodega Pirineos | And 2 more authors.
Journal of the Science of Food and Agriculture | Year: 2014

BACKGROUND: The effects of two different operations in the vineyard (basal leaf plucking and head trimming) on the synthesis of aromatic precursors in the grape and their impact on wine aroma have been studied and compared with a control sample. The study was carried out over two consecutive years with four different varieties. Glycosidic precursors were analysed in grapes and volatile compounds were studied in the wines. ANOVA studies were performed to study the effect of the vintage, variety and treatment for each of the compounds released from their precursors. RESULTS: Regarding treatment, the highest values in the concentration of free aroma compounds were achieved in the leaf plucking grapes, except for Chardonnay. Significant and positive correlations between aromatic precursors of terpenes present in grapes and their released form in wines were found for all varieties. For norisoprenoids, significant and positive correlations were exclusively found for Chardonnay and for phenols and vanillins in the year 2010 the correlations were high in three of the four varieties studied. CONCLUSION: In the assays of the 2 years, more precursors were synthesised in Merlot, Gewurztraminer and Tempranillo grapes if the vineyards were plucked. © 2014 Society of Chemical Industry. Source

Concejero B.,University of Zaragoza | Hernandez-Orte P.,University of Zaragoza | Astrain J.,Bodega Pirineos | Lacau B.,Bodega Pirineos | And 2 more authors.
LWT - Food Science and Technology | Year: 2016

Polyfunctional mercaptans and their cysteinilated and glutathionilated precursors were analysed in samples taken at different densities during the alcoholic fermentation of five tanks in a two-year study. The aim was to determine when these compounds are extracted, released and degraded during this process. At the beginning of the fermentation, an increase in the concentration of cysteine-3-mercaptohexan-1-ol (CYSMH) and glutathione-3-mercaptohexan-1-ol (GLUMH) was observed, due to the extraction of these precursors from skin to must. Later on a decrease in the concentration was perceived as CYSMH and GLUMH broke up to release the polyfunctional mercaptans and other non-identified compounds. The concentration of polyfunctional mercaptans increased during alcoholic fermentation. There are significant differences in the concentration of all the volatile thiols and its precursors, between samples taken at different moments of the fermentation in each tank.However, even if a large concentration of CYS/GLU precursors in must was released, only a small concentration of polyfunctional mercaptans liberated from them were found in wine. Probably, these compounds are labile and parts of them were degraded during the fermentation process. © 2015 Elsevier Ltd. Source

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