1,721,219 research outputs found
Realizzazione dei testi relativi alla “Caratterizzazione sensoriale e chimicofisica dei vini rientranti nel progetto di realizzazione dell’Atlante del Vino Italiano”
No full textMetaboliti secondari odorosamente attivi e loro precursori in uve da vino in disidratazione: studio delle cinetiche di accumulo nelle diverse frazioni dell'acino e loro trasferimento ed evoluzione nel vino
No full textIl compito dell'UO sarà quello di monitorare le cinetiche di accumulo nelle diverse porzioni dell'acino di metaboliti secondari odorosamente attivi e di loro precursori nel corso della disidratazione condotta in condizioni ambientali controllate. Leanalisi dei costituenti volatili liberi e in forma di precursori glicosilati sarà condotta mediante SPE/GC-MS. Particolare attenzione sarà rivolta al rilevamento dei markers volatili la cui biogenesi è legata a quegli enzimi la cui attività sarà valutata dall?UO1. Allo scopo di valutare la composizione delle frazioni aromatiche delle diverse componenti dell'acino, verranno analizzati separatamente campioni ottenuti dalle bucce e dalla polpa di ciascuna varietà nelle diverse condizioni e gradi di disidratazione. L'attività sperimentale proseguirà sui vini ottenuti dalla stesse uve. La composizione qualitativa e quantitativa della frazione volatile dei vini sarà analizzata allo scopo di seguire il trasferimento di questi metaboliti secondari dalle uve disidratate al vino, di valutarne il loro impatto sensoriale, la loro shelf-life/stabilità e la loro evoluzione
Changes in the concentration of yeast-derived volatile compounds of red wine during malolactic fermentation with four commercial starter cultures of Oenococcus oeni
No full textThe effects of malolactic fermentation (MLF) on the concentration of volatile compounds released by yeasts during the production of red wine were investigated by inoculation with four commercial starters of Oenococcus oeni. Volatile compounds in wine at the end of MLF were extracted, analyzed by GC-MS and GC, and compared with those extracted form a noninoculated reference sample. Several esters known to play a role in the aroma profile of red wine, such as C4-C8 ethyl fatty acid esters and 3-methylbutyl acetate, were found to increase with MLF, and their final concentration was dependent on the bacterial starter employed for the induction of MLF. The overall increase of ethyl fatty acid esters was generally larger than the one observed for acetate esters. Ethyl lactate, 3-hydroxybutanoate, 2-phenylethanol, methionol, and γ-butyrolactone were also increased by bacterial metabolism. The impact of MLF on other volatiles or red wine, including several higher alcohols, fatty acids, and nitrogen compounds, was generally negligibl
Changes in the concentration of yeast-derived volatile compounds of red wine during malolactic fermentation with four commercial starter cultures of Oenococcus oeni
No full textThe effects of malolactic fermentation (MLF) on the concentration of volatile compounds released by yeasts during the production of red wine were investigated by inoculation with four commercial starters of Oenococcus oeni. Volatile compounds in wine at the end of MLF were extracted, analyzed by GC-MS and GC, and compared with those extracted form a noninoculated reference sample. Several esters known to play a role in the aroma profile of red wine, such as C4-C8 ethyl fatty acid esters and 3-methylbutyl acetate, were found to increase with MLF, and their final concentration was dependent on the bacterial starter employed for the induction of MLF. The overall increase of ethyl fatty acid esters was generally larger than the one observed for acetate esters. Ethyl lactate, 3-hydroxybutanoate, 2-phenylethanol, methionol, and γ-butyrolactone were also increased by bacterial metabolism. The impact of MLF on other volatiles or red wine, including several higher alcohols, fatty acids, and nitrogen compounds, was generally negligibl
The influenceof malolactic fermentation and “Oenococcus oeni” strain on glycosidc aroma precursors and related volatile compounds of red wine
No full textFree and hydrolytically released volatile compounds of Vitis vinifera L. cv. Fiano grapes as odour-active constituents of Fiano wine
No full textGrape-derived volatile compounds, including those released from odourless glycosidic precursor present in the grape, are strongly associated with the varietal aroma characteristic of non-aromatic wines. In this study, free and glycosidically bound volatile compounds of Fiano grapes have been identified and quantified by means of gas chromatography-mass spectrometry (GC-MS). The free volatile fraction of Fiano grapes was mainly characterised by the occurrence of several aliphatic alcohols, with minor amounts of the monoterpenes linalool and geraniol, and traces of the norisoprenoid β-damascenone. The volatile fraction obtained from either enzymatic or acid hydrolysis of juice glycosides was more complex, and contained compounds belonging to the chemical classes of terpenes, norisoprenoids, benzenoids, and aliphatic alcohols. Linalool, geraniol, teprinen-4-ol, 1,1,6-trimethyl-1,2-dihydronaphtalene (TDN), β-damascenone, (E)-1-(2,3,6-trimenthylphenyl)buta-1,3-diene (TPB), ethyl cinnamate, and 4-vinyl guaiacol were detected by GC-olfactometry (GC-O) as odorants of young Fiano wine that were formed through hydrolysis of grape precursors. Pathways of formation of these compounds during winemaking were investigated. Yeast-driven enzymatic hydrolysis of glycosides was the major route for linalool and geraniol formation, while acid hydrolysis led to the formation of terpinen-4-ol, TDN, β-damascenone, TPB, and ethyl cinnamat
The influenceof malolactic fermentation and “Oenococcus oeni” strain on glycosidc aroma precursors and related volatile compounds of red wine
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