Volatile and glycosidically bound composition of Loureiro and Alvarinho wines

Composition of Loureiro and Alvarinho wines from the Vinhos Verdes region, respecting free volatile compounds as well as glycosidically bound aroma precursors, was exhaustively determined by GC-MS after adsorption on XAD-2 resin. On the whole, were identified and quantified 120 volatile compounds in the free fraction and 77 glycosidically bound compounds, belonging to C6-compounds, alcohols, fatty acids ethyl esters, esters of organic acids, acetates, monoterpenic alcohols, monoterpenic oxides and diols, C13-norisoprenoids, volatile phenols, volatile fatty acids and carbonyl compounds. Globally, the wines of the two cultivars present similar composition on volatiles. However, respecting varietal compounds, Loureiro wines are richer than Alvarinho ones with regard to C6-compounds and monoterpenic compounds, occurring the opposite for volatile phenols. It was also demonstrate that wines of both varieties may benefit the aroma reserve, present as glycoconjugates, as it is susceptible of being technologically explored. Linalool, Ho-trienol, α-terpineol, contributing with fruity and floral notes, and β-damascenone mostly for Alvarinho, confering tropical fruit notes, are the varietal compounds which may particularly influence the aroma of these wines. Respecting fermentative compounds, Alvarinho is also particularly rich in fatty acids ethyl esters related to lipid metabolism and acetates of fusel alcohols, which can provide it a fruity character; Loureiro contains higher levels of esters of organic acids and 2-phenylethanol, conferring fruity and floral notes. Sensory analysis agree with chemical analyses showing a pronounced tree and tropical fruit character for Alvarinho wines while Loureiro wines present more intense citrus fruit notes.Centre of Biological Engineering of Universidade do Minho; Estação Vitivinícola Amândio Galhano (EVAG); Solar de Serrade; EVAG; Comissão de Viticultura da Região dos Vinhos Verdes

Characteristics of winery and distillery wastewaters and implications for treatment of carbon in the wastewaters by application to soil

The composition and source of organic and inorganic components of winery and distillery wastewaters, have been detailed. Both winery and distillery wastewaters had a high carbon content, dominated by simple organic substances derived from grapes and wine. The inorganic composition of the wastewaters was a product of minerals contained in the water used for cleaning, cleaning agents, components added by grapes, and substances used for the manufacture of wine. The analyses formed part of an investigation on the removal of water-soluble carbon from the wastewaters by the processes of adsorption and microbial decay, in soil. Effects of the organic characteristics of the wastewaters, on the rate and extent of removal of the water-soluble carbon in soil, are outlined. / La composition et les sources des constituants organiques et inorganiques des effluents vinicoles provenant de cuviers et de distilleries ont été détaillées. Les effluents vinicoles, recueillis dans les distilleries et dans les cuviers, contiennent, dans les deux cas, un fort pourcentage de carbone principalement composé par des substances organiques simples, héritées en majeure partie des grappes et du vin. La composition inorganique des effluents vinicoles est le produit de minéraux provenant des eaux utilisées pour le nettoyage, des produits d'entretien, de composants de la grappe et de substances utilisées pour l'élaboration du vin. Ces analyses font partie d'une étude sur l'élimination du carbone hydrosoluble des effluents vinicoles par le processus d'adsorption et de décomposition microbienne du sol. Les effets de la composition organique des effluents vinicoles sur le taux et l'étendue du carbone hydrosoluble pouvant être éliminé dans le sol ont été résumés

Changes in the concentration of volatile oak compounds and esters in red wine stored for 18 months in re-used French oak barrels

Studies were made of changes in concentration of oak-wood-derived volatiles and the evolution of esters in red wine during storage in twice-used French oak barrels. Wine samples were taken after 8, 10, 12, 15, and 18 months maturation in the barrels. Results showed that most of the volatile compounds extracted from the wood (furanic compounds, volatile phenols, lactones) reached maximum concentration between 10 and 12 months of barrel storage. After 18 months of maturation many of the compounds showed concentrations similar to those found after 10 to 12 months. However, the concentrations of furfural, 5-methyl furfural, furfuryl alcohol, coniferaldehyde, acetovanillone and phenol in wines aged for 18 months were lower than those reached after 10 to 12 months. The concentration of the ethylphenols increased right up to 18 months of ageing, which can only have a negative impact on the quality of the wine. There were few modifications in the concentration of esters, except for ethyl lactate which reached peak concentration after 12 months maturation and decreased thereafter