219 research outputs found
Application of gas chromatography on the evaluation of grape and wine aroma in atlantic viticulture (NW iberian peninsula)
Influence of Saccharomyces cerevisiae Strains on General Composition and Sensorial Properties of White Wines Made from Vitis vinifera cv. Albariño
Yeast strains contribute to the oenological and sensorial characteristics of the wines they produce. The present study was performed to determine the influence of Saccharomyces cerevisiae strains on the composition and sensorial properties of Albariño wine. The must obtained from Albariño grapes was inoculated with 12 different yeast strains isolated from a single winery in Galicia, Spain. Chemical and sensorial analyses were performed on the final wines, which differed depending on the yeast strain used
First study on volatile composition of three Vitis vinifera cultivars from Betanzos (NW Spain) : blanco lexítimo, agudelo and serradelo
Wine aroma is formed by volatile compounds of different chemical nature and origins.
Compounds arising from grape metabolism vary as a function not only of the variety but also
of climatic conditions and others. Betanzos is the most northern viticole geographic area from
Galicia (NW Spain). Wines produced from Vitis vinifera cv. Blanco lexítimo, Agudelo and
Serradelo from Betanzos (NW Spain), harvest in 2006 and 2007, were submitted to gas
chromatography (GC/FID).
A total of 35 varietal and fermentative aroma compounds were identified and quantified
which include terpenes and C13-norisoprenoids, alcohols, acids, esters, phenol volatiles and
C6 compounds. The results for quantification of the aroma compounds in the three varieties
from Betanzos shows that the mean concentration between years was 25039.42ug/L for
Blanco lexítimo 21913.2ug/L for Agudelo and 19804.6μg/L for Serradelo variety. Alcohols,
acids and esters were the most important volatile compounds in the varieties from Betanzos.El aroma del vino está formado por compuestos volátiles de diferente naturaleza y origen.
Estos compuestos varian no solo con la variedad de uva sino también con las condiciones
climáticas y otros factores. Betanzos es la zona vitícola situada más al norte de Galicia
(Noroeste de España). Los vinos producidos con tres variedades de Betanzos, Blanco
lexítimo, Agudelo y Serradelo cultivadas en las cosechas 2006 y 2007, fueron analizados
mediante GC/FID.
En los vinos fueron identificados y cuantificados un total de 35 compuestos varietales y
fermentativos, en cuales se incluyen C13-norisoprenoides, alcoholes, acidos, esters, fenoles
volatiles y otros. Los resultados de la cuantificación de los compuestos del aroma en los vinos
de las tres variedades de Betanzos muestra que la concentración mediaentre los años
estudiados fue de 25039.42ug/L para Blanco lexítimo 21913.2ug/L para Agudelo y
19804.6μg/L para Serradelo. Alcoholes, acidos and esteres fueron los compuestos más
importantes en los tres vinos elaborados con las variedades de Betanzos, siendo el más
aromático el elaborado con la variedad Blanco lexítimo, caracterizado por aromas frutales.Xunta de Galicia (Spain) and Adega Lorenzo Bescansa S.U.L
Fermented beverages : process technology and management, volatile compounds, instrumental methods of analysis
The authors have been developed their main efforts studying fermented beverages, being wine the most important product [1]. Recently, other fermented products, obtained from various fruits, namely tropical fruits, and even from cheese whey have been studied [2]. The main goal is to study the technological parameters which may influence the quality of the final products, in order to manage the process, accurately. As aroma is one of the most important attributes of fermented beverages, the development of analytical methodologies to identify and quantify key volatile compounds, was also an objective.
Volatile compounds related to different origins (varietal, fermentative, post-fermentative) and belonging to various chemical families (terpenes, norisoprenoids, alcohols, esters, volatile fatty acids, volatile phenols, …) were studied in final products as well as in raw-materials, namely grapes. Correlation between chemical and sensory analyses has been also considered.
Methodologies used to extract volatile compounds from beverages include liquid-liquid micro-extraction, solid-phase extraction and solid-phase micro-extraction. Gas chromatography with flame ionisation, pulsed photometric and mass detectors was used.
The main results may be summarized as followed: characterization and discrimination of grape varieties based on varietal volatile composition, from Vinhos Verdes region and from Galicia (Spain); influence of viticultural and some technological parameters and storage conditions on the volatile composition of grapes and wines; correlation between sensory (aroma) and chemical analysis (volatile compounds); implementation of simple and accurate analytical methodologies to quantify volatile compounds of fermented beverages; characterisation, respecting volatile compounds, of diverse beverages, namely obtained from tropical fruits and from cheese whey
Characterization and differentiation of seven vinhos verdes grape varieties on the basis of monoterpenic and C13-norisoprenoid compounds
The aromatic profiles of the 7 recommended cultivars for Vinho Verde wine production
have been established with respect to monoterpenic and C13-norisoprenoids compounds,
present either in free or in glycosidically bound fractions. Eighteen monoterpenic
compounds have been identified and quantified in the free form and 22 in the
glycosidically bound form. Fifteen C13-norisoprenoids compounds have been identified
and quantified in the glycosidically bound form. Loureiro variety can be easily
differentiating from the 6 other varieties by important levels of linalool in the free
fraction, above the odour perception threshold; in contrast, Alvarinho, Avesso, Arinto,
Azal and Trajadura, geraniol prevails. Batoca variety showed a very poor monoterpenic
profile in the free form. In the glycosidically bound form Alvarinho is the richest in total
concentration of monoterpenic compounds, followed by Loureiro.Les profils aromatiques des 7 cépages recommandés pour la production de Vinho Verde
ont été établis en ce qui concerne les C13-norisoprenoïdes et les composés
monoterpéniques, trouvés dans les deux fractions de l´arôme, livre et glycosillée. Dix-huit
monoterpènes ont été identifiés et quantifiées, dans la fraction libre, et d’autres 22
attachés à des glycosides. Quinze C13-norisoprenoïdes ont été identifiés et quantifiés dans
la fraction glycosillée. Le cépage Loureiro peut facilement être différencié des autres 6
variétés par les niveaux importants de linalol dans la fraction libre, au-dessus du seuil de
perception olfactive; par contre, le geraniol prédomine pour Alvarinho, Avesso, Arinto,
Azal et Trajadura. Le cépage Batoca a montré un très pauvre profil monoterpénique dans
la fraction libre. Pour la fraction glycosillée, le cépage Alvarinho est le plus riche, en ce
qui concerne la concentration totale en composés monoterpéniques ; le Loureiro est le
deuxième cépage plus riche.Estação Vitivinícola Amândio GalhanoDivisão de
Vitivinicultura e Fruticultura da Direcção Regional de Agricultura de Entre Douro e
Minh
Volatile composition of Red Mencia and Souson cultivars from Rias Baixas and Valdeorras AOC (NW Spain)
Mencía and Sousón are two red Vitis vinifera cultivars grown in two geographic areas from Galicia (NW Spain), Appellation of Origin Controlled Valdeorras and Rías Baixas. Valdeorras AOC is situated in south east Galicia, with Continental climate, slate soil, gentle temperature and rainfall and Rías Baixas AOC is located in the southwest Galicia, near of the sea, with Atlantic climate, siliceous soil, and slightly higher temperature and rainfall than the first one. The aim of this study was to carry out a first approximation to determinate the influence of terroir on volatile composition of these red cultivars grown in Galicia. Grapes of Mencía and Sousón, collected in 2009 vintage, were crushed and the musts volatiles were extracted using Solid Phase Extraction (SPE). The identification and quantification was performed by gas chromatography-mass spectrometry (GC-MS) in free and bound form. The results showed a greater effect of terroir in bound compounds (alcohols, volatile phenols, C13-norisoprenoids and volatile fatty acids) between geographic areas for the two cultivars studied. In free fraction C6-compounds and carbonyl compounds showed variability between geographic areas for the cultivars
Determination of odorants in varietal wines from international grape cultivars (Vitis vinifera) grown in NW Spain
This work was carried out to investigate the odorants found in ten varietal wines from different international grape cultivars (Merlot, Cabernet Sauvignon, Pinot noir, Tempranillo, Sauvignon blanc, Riesling, Chardonnay, Pinot gris, Pinot blanc and Gewürztraminer) grown in northwest Spain. Monoterpenes, alcohols, fatty acids, ethyl esters, acetates and volatile phenols were determined by gas chromatography-mass spectrometry (GC-MS). The results showed that Gewürztraminer white wines had the highest concentration of volatile compounds (35.7 mg/L). Monoterpenes, linalool, terpineol, citronellol and nerol were detected only in Riesling and Gewürztraminer white wines. In the red wines, Cabernet Sauvignon followed by Merlot wines showed the highest concentration of total volatile composition (55.60 mg/L and 50.90 mg/L respectively), characterised by a higher concentration of alcohols. Based on the individual odour threshold, white Gewürztraminer and red Pinot noir wines showed the highest total OAV value. ANOVA has shown significant differences among wines. Principal component analysis performed a grouping of the monovarietal wines – Sauvignon blanc-Pinot blanc-Riesling and Pinot gris gris-Gewürztraminer in the white wines, and Cabernet Sauvignon-Tempranillo in the red wines
Correlation between instrumental and sensory analysis for the characterization of Vitis vinifera wines
In this work, sensory analysis of was used to evaluate the wine aroma character with different
aroma attributes according to Norm ISO 11035.1 In parallel wine volatiles were identified and
quantified by gas chromatography according the methodology proposed by Oliveira et al.
(2006).2
The objective of this work was to study the correlation between instrumental analysis and
sensory perception of wine constituents.
Thirty-five Albariño white young wines from 2006 vintage were evaluated by GC-FID and
sensory analysis by trained and native panel composed by 10 wine tasters from Appellation of
Origin Rias Baixas (Galicia, Spain). Forty volatile compounds were identified and quantified
by Gas Chromatography and forty-seven aroma descriptors were developed using quantitative
descriptive analysis and evaluated with line scaling method.
Principal component analysis showed the distribution of the wines in basis to chemical and
sensory characteristics. The correlation coefficients of the flavour scores between sensory
evaluation and instrumental analysis (R2 > 0.50) were found for methanollacticvanilla,
guaiacolhoney, 3-methyl-1-propanolgreen-pepper, 1-butanolliquorice, ethyl lactategreenpepper
liquorice. These correlations linking chemical compounds and sensory descriptors
may be attributed to possible relations between them, to the presence of other produced
compounds which were not analysed or, to some associations among the analysed
compounds
Easy and accurate methodology to quantify volatile compounds in fermented beverages
Volatile compounds of fermented beverages may derive from raw matter, but the majority are formed during fermentative processes. In the some specific cases, e. g. wines, they may also arise
during conservation and ageing. These volatiles belong to a diversity of chemical families, including alcohols, esters, fatty acids, volatile phenols, terpenes and norisoprenoids. Levels of
individual compounds may range from few ng/L to hundreds of mg/L. Although major volatiles may be analysed directly by gas chromatography, most of them needs a previous step of
concentration. Concentration was traditionally achieved by solvent extraction, liquid-liquid mixture, soxhlet and SPE, followed by evaporation; more recently solvent-free extractive techniques SPME and SBSE, became usual due to their detection limits and selectivity. However, these techniques have some drawbacks: environmental aspects when using large quantities of
solvents, price, needs of specialized equipment and workmanship. Furthermore, chromatographic detectors may be selective, e. g. pulse flame photometric detector (PFPD) for sulphurous
compounds or nitrogenous compounds, or somewhat universal as mass spectrometer (MS). However, although MS permits the quantification of a wide range of volatiles, the equipment is very expensive and cost-maintenance. Another detector largely used by research centres and institutions linked to beverages sector, the flame ionisation detector, acquire attractiveness due to its good response to the methyl groups of organic compounds and its appellative price.
These constraints makes difficult to achieve a universal methodology to analyse, in a single and quick approach, all the constituents of a fermented beverage like wine, beer or other products
obtained by the fermentation of fruit juices. Moreover, when analysts of research centres and tutelary institutions need to compare samples, to quantify some few key volatile compounds or
even to confirm its authenticity, they aspire for an easy and accurate methodology, which additionally uses inexpensive equipment.
This work refers to the implementation of a quick methodology to quantify volatile compounds of fermented beverages, carried out by liquid-liquid micro-extraction followed by chromatographic analysis. The optimized methodology, reached to maximize the number of
extractions per day, only uses 8 mL of sample and 400 L of dichloromethane. Each battery of extracts, ready for chromatographic analysis by GC-FID, may be obtained after 30 min, and only
uses ordinary labware. Although the proposed methodology may permit the identification and quantification of a large number of compounds, it was implemented for 40, belonging to the following families: alcohols, esters, terpenes, volatile fatty acids, volatile phenols and norisoprenoids. Validation was performed in terms of linearity, limits of detection and quantification, repeatability,
reproducibility and recovery
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