The paper is developed in 3 fundamental parts. The first part describes the varietal aromas, typical of the various types of grapes, which allow to contribute from a sensorial and organoleptic point of view on the aroma of the product and in particular the fermentation aromas, the most important ones, which originate in the fermentation process, enhancing the sensorial perception. The aroma of wines is determined by the single substances that make up the same, each of which contributes, based on its concentrations and on the relationships with the other components to olfactory perceptions. After a description of the varietal aromas, a classification of the same aromatic compounds and their peculiarities is illustrated according to the class concerned. The focus is on a particular compound, the methoxypirazines or pirazines, characterized by a strong impact at the nasal level and that is perceived even if they are present in a few ng/l. The second part of the work focuses on the history of pirazines, they are aromatic compounds that characterize some grape varieties. Discovered in 1975, they have a connotation that makes the wine unique and distinctive, allowing it to stand out compared to the multiplicity of wines on the market. It is a singular aroma that in some cases can have a negative effect, as such strong aromas are not always appreciated and above all not all consumers have the skills to evaluate the qualitative aspect of the product in all its facets. Its typicality is given by the varietal aromas, that is typical of each grape variety. It is important the role of the territory from which the vine originates, the weather conditions of that place, the mineral characteristics of the soil in which it is cultivated, as they characterize and make unique the wine that is produced. In the third part particular attention will be paid to the description of the methods of detection of volatile compounds present in wines such as gas chromatography, HPLC, isotopic dilution (mass spectrometry) and head space, essential for having a quantitative parameter, but also essential for a qualitative evaluation parameter. The factors influencing the development of methoxypyrazines in wines will be proposed, as we will see the climate, the territory, the water ratio, the exposure to the sun, can influence the percentage of methoxypyrazines. We will then see how it is possible to reduce through the various methods the content of pirazines and their, sometimes unpleasant, green aroma.
L’elaborato si sviluppa in 3 parti fondamentali. Nella prima parte vengono descritti gli aromi varietali, tipici delle varie tipologie di uve, i quali permettono di contribuire da un punto di vista sensoriale e organolettico sull’aroma del prodotto ed in particolar modo gli aromi di fermentazione, quelli quantitativamente più rilevanti, che si originano nel processo di fermentazione, valorizzando la percezione sensoriale. L’aroma dei vini è determinato dalle singole sostanze che compongono lo stesso, ognuna delle quali contribuisce, in base alle sue concentrazioni e ai rapporti con gli altri componenti alle percezioni olfattive. Dopo una descrizione degli aromi varietali, è illustrata una classificazione degli stessi composti aromatici e delle loro peculiarità a seconda della classe interessata. Il focus è su un composto in particolare, le metossipirazine o pirazine, caratterizzate da un forte impatto a livello nasale e che si percepisce seppur esse siano presenti in pochi ng/l. La seconda parte dell’elaborato si concentra sulla storia delle pirazine, esse sono dei composti aromatici che caratterizzano alcune varietà di uve. Scoperte nel lontano 1975, hanno una connotazione che rende il vino unico e distintivo, permettendogli di contraddistinguersi rispetto alla molteplicità di vini presenti in commercio. È un aroma singolare che in alcuni casi può influire negativamente, poiché aromi così decisi non sono sempre apprezzati e soprattutto non tutti i consumatori hanno le competenze per valutare l’aspetto qualitativo del prodotto in tutte le sue sfaccettature. La sua tipicità è data dagli aromi varietali, ovvero aromi tipici di ogni singolo vitigno. Risulta essere rilevante il ruolo del territorio da cui si origina il vitigno, le condizioni metereologiche di quel luogo, le caratteristiche minerali del suolo in cui è coltivato, in quanto caratterizzano e rendono unico il vino che viene prodotto. Nella terza parte verrà posta particolare attenzione sulla descrizione delle metodiche di rilevazione dei composti volatili presenti nei vini come la gascromatografia, l’HPLC, la diluizione isotopica (spettrometria di massa) e head space, essenziali per avere un parametro quantitativo, ma essenziale anche per un parametro di valutazione qualitativo. Verranno proposti i fattori che influenzano lo sviluppo delle metossipirazine nei vini, in quanto come si vedrà il clima, il territorio, il rapporto idrico, l’esposizione al sole, possono influenzare metossipirazine. Vedremo allora com’è possibile ridurre attraverso le varie metodiche il contenuto la percentuale di di pirazine e il loro, a volte sgradevole, aroma verde.
Le pirazine: metodiche di rilevazione e tecniche per la loro modulazione nei vini
MONTORI, ILARIA
2021/2022
Abstract
The paper is developed in 3 fundamental parts. The first part describes the varietal aromas, typical of the various types of grapes, which allow to contribute from a sensorial and organoleptic point of view on the aroma of the product and in particular the fermentation aromas, the most important ones, which originate in the fermentation process, enhancing the sensorial perception. The aroma of wines is determined by the single substances that make up the same, each of which contributes, based on its concentrations and on the relationships with the other components to olfactory perceptions. After a description of the varietal aromas, a classification of the same aromatic compounds and their peculiarities is illustrated according to the class concerned. The focus is on a particular compound, the methoxypirazines or pirazines, characterized by a strong impact at the nasal level and that is perceived even if they are present in a few ng/l. The second part of the work focuses on the history of pirazines, they are aromatic compounds that characterize some grape varieties. Discovered in 1975, they have a connotation that makes the wine unique and distinctive, allowing it to stand out compared to the multiplicity of wines on the market. It is a singular aroma that in some cases can have a negative effect, as such strong aromas are not always appreciated and above all not all consumers have the skills to evaluate the qualitative aspect of the product in all its facets. Its typicality is given by the varietal aromas, that is typical of each grape variety. It is important the role of the territory from which the vine originates, the weather conditions of that place, the mineral characteristics of the soil in which it is cultivated, as they characterize and make unique the wine that is produced. In the third part particular attention will be paid to the description of the methods of detection of volatile compounds present in wines such as gas chromatography, HPLC, isotopic dilution (mass spectrometry) and head space, essential for having a quantitative parameter, but also essential for a qualitative evaluation parameter. The factors influencing the development of methoxypyrazines in wines will be proposed, as we will see the climate, the territory, the water ratio, the exposure to the sun, can influence the percentage of methoxypyrazines. We will then see how it is possible to reduce through the various methods the content of pirazines and their, sometimes unpleasant, green aroma.File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/35796