CIBICI   14215
CENTRO DE INVESTIGACION EN BIOQUIMICA CLINICA E INMUNOLOGIA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Assessment of Wine Variety Based on VOCs Composition and Chemometrics. A Case Study: Red Wines from the Valley of Tulum (San Juan-Argentina)
Autor/es:
FABANI, M.P.; RAVERA, M.J.A.; WUNDERLIN, D. A.
Lugar:
Torremolinos. España
Reunión:
Congreso; 4th Annual Meeting and Conference: Lost without TRACE; 2008
Institución organizadora:
TRACE CONSORTIA EU
Resumen:
ESTE TRABAJO RECIBIÓ EL SEGUNDO PUESTO ENTRE LOS MEJORES TRABAJOS DEL CONGRESO. The aroma is one of the most important factors contributing to wine character and quality. It is also a key attribute for consumers. Aroma is produced by a complex mixture of volatile organic compounds (VOCs), including aldehydes, higher alcohols, ethyl esters, fatty acids, monoterpenes, etc. Some of these VOCs come naturally from the grapes and are typical of a wine variety; however, most of them are formed during the fermentation process and wine ageing as well. Wine aroma is influenced by several factors, like grape variety, growing region, climate, viticulture practices, vinification process, ageing processes, etc. The study of VOCs composition could be very useful for wine authentication, evaluation of wine-age as well as a key contribution for the traceability of this product.                We studied VOCs profile in red wines from the Valley of Tulum (Province of San Juan-Argentina), aiming to assess if VOCs profile could allows to differentiate between different varieties produced in this region. So, we studied 100% pure wine varieties, during four consecutive vintages (2004–2007). Studied varieties were: Syrah (n= 8), Cabernet Sauvignon (n= 10), Malbec (n= 8) and Bonarda (n= 6), which were provided by the cellar Augusto Pulenta, Finca - "Doña Filomena" (San Juan, Argentina).                VOCs were determined by HS-SPME, coupled to GC-MS, using a DVB-Carboxen-PDMS fibre. Each sample was analyzed by triplicate. First, we did a qualitative analysis of VOCs present in different samples. Then we applied linear discriminant analysis (LDA) to select seven compounds, which were the most significant to differentiate among wine varieties. These components were identified and quantified using pure standards.                The application of forward stepwise LDA on quantitative data matrix allows 90% right discrimination among four varieties studied, affording six descriptors: 1-Hexanol (herbaceous-vegetal), 3-Furaldehyde (sweet-caramel), Isopentyl acetate (banana), Benzyl alcohol (flowery-sweet), Ethyl hexanoate (green apple) and Ethyl octanoate (ripe fruits-pear-sweet). Box plots of these selected variables shows that Ethyl octanoate differentiates Syrah, Benzyl alcohol and 1-Hexanol discriminate Cabernet Sauvignon and Malbec, respectively. Bonarda present the higher concentration of 3-Furaldehyde. VOCs profiles were similar in the four vintages analyzed. So far, we conclude that the aromatic descriptors: Ethyl octanoate, Benzyl alcohol, 1-Hexanol and 3-Furaldehyde could be used as chemical markers of variety among red wines of the studied region. Considering that yeast used during fermentation were the same for four varieties studied, it is evident that the VOCs profile of studied wines are influenced by the grape variety. Further work is necessary to assess differences in VOCs for a given wine variety produced in different regions, thus contributing to wine authentication and traceability.