Ellagitannins from Portuguese oak wood (Quercus pyrenaica Willd.) used in cooperage: influence of geographical origin, coarseness of the grain and toasting level

Abstract

The ellagitannins and ellagic acid from extracts of Portuguese oak wood chips (Quercus pyrenaica) used in cooperage from different origins (Gerês and Guarda forests) were analysed by HPLC. The results were compared with the ellagitannin content of wood chips obtained from American (Q. alba) and French (Q. petraea) oak. The influence of heat treatment and the coarseness of the grain on ellagitannins and ellagic acid were also studied. Five ellagitannins (vescalagin, castalagin, roburin D, roburin E and grandinin) and ellagic acid were quantified. Vescalagin and castalagin were the most abundant individual ellagitannins in all of the oak wood chips studied. Portuguese oak wood had the highest content of ellagitannins and ellagic acid, followed by the French and American oaks. The geographical origin of Portuguese oak and the coarseness of the grain of French oak affected the content of ellagitannins and ellagic acid. In general, the ellagitannin content decreased with the toasting process, while the ellagic acid content increased. The toasting process had the highest impact on ellagitannin composition in comparison to the other variables studied.

Comparative analysis of volatile and phenolic composition of alternative wood chips from cherry, acacia and oak for potential use in enology

“…For the different oak wood species studied, the individual phenolic compounds detected were mainly low molecular weight phenolic compounds, resulting primarily from thermodegradation of lignin during the toasting process (for example, syringaldehyde, coniferaldehyde and vanillic acid). In addition, French and Portuguese oak wood extract samples showed higher individual phenolic content than American oak wood extract samples, confirming previously results obtained by other authors [2,9].…”

Quercus humboldtii(Colombian oak): Characterisation of wood phenolic composition with respect to traditional oak wood used in oenology

“…The fact that Q. sessiliflora contained higher amounts of the individual ellagitannins than Q. alba has been widely reported (Canas et al, 2000;Cadahía et al, 2001b). In addition, the concentration of ellagitannins is affected by a large number of interdependent factors, including the species (Canas et al, 2000;Doussot et al, 2002;Jordão et al, 2007), forest origin (Doussot et al, 2002;Jordão et al, 2007), heartwood age (Matricardi and Waterhouse, 1999), grain coarseness (Jordão et al, 2007) among others. Some authors (Masson et al, 1995;Doussot et al, 2002) reported that species discrimination and especially the species-provenance combination are the main factors determining tannin levels.…”

“…Very few oaks fully meet these conditions, and those most used belong to the white oak group. In the last few years, other white oaks have been studied for use in oenology with the aim of comparing their characteristics with those of traditional oaks (Q. robur, Q. sessiliflora and Q. alba), as is the case of Q. pyrenaica and Q. faginea (Canas et al, 2000;Cadahía et al, 2001a,b;Fernández de Simón et al, 2006;Jordão et al, 2007;Gonçalves and Jordão, 2009;Cabrita et al, 2011;Gallego et al, 2012). …”

Phenolic Compounds in Fruit Beverages

“…The four monomeric ellagitannins and the monomeric gallotannin are derived from the wood (oak or chestnut), in which they are present in higher amounts, together with four dimeric ellagitannins (roburins A, B, C and D) [67,[123][124][125][126], and with other dimeric and trimeric gallotannins [127,128]. Therefore, their low content or absence in the aged wine spirits may result from the thermal degradation during the heat treatment of the wood [117,126,[129][130][131].…”