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

Abstract

SUMMARYThe use of new oak barrels and the demand for oak wood in oenology is increasing. Thus, it is necessary to search for new wood sources to supply the current demand in cooperage. The aim of this work was to study the composition of ellagitannins and low molecular weight phenolic compounds (LMWP) by HPLC-DAD of green wood Quercus humboldtii Bonpl. (Colombian), compared to the species typically used in cooperage: Quercus sessiliflora Salisb. (French and Romanian) and Quercus alba L. (USA). In Colombian oak wood, the same LMWP and ellagitannins as in the traditional species were identified. The most abundant LMWP was ellagic acid, and its concentration was lower in Q. humboldtii and Q. alba than in Q. sessiliflora, so these two presented a lower content of phenolic acids. As regards phenolic aldehydes, Colombian oak wood only showed significant differences in the content of coniferyl and sinapic aldehydes in relation to French oak. Finally, the total ellagitannin content of Q. humboldtii was lower than that of European oaks and similar to that of American oak (Q. alba). None of the ellagitannins studied presented significant differences compared to Q. alba. Therefore, Q. humboldtii wood was more similar in terms of phenolic composition to Q. alba than to Q. sessiliflora. RESUMOO uso de novos barris de carvalho e a procura de madeira de carvalho em enologia estão aumentando. Assim, torna-se necessária a investigação de novas fontes de madeira para satisfazer a atual procura pela tanoaria. O objetivo deste trabalho foi estudar a composição de taninos elágicos e compostos fenólicos de massa molecular baixa (LMWP) por HPLC-DAD de madeiras verdes de Quercus humboldtii Bonpl. (colombiano), em comparação com espécies tipicamente usadas em tanoaria: Quercus sessiliflora Salisb. (francês e romeno) e Quercus alba L. (EUA). Na madeira de carvalho da Colômbia, foram identificados os mesmos LMWP e taninos elágicos do que nas espécies tradicionais. O LMWP mais abundante foi o ácido elágico, e sua concentração foi menor em Q. humboldtii e Q. alba do que em Q. sessiliflora, portanto estas duas madeiras apresentaram menor teor de ácidos fenólicos. Em relação aos aldeídos fenólicos, a madeira de carvalho colombiano mostrou diferenças significativas no teor de aldeídos coniferílico e sinápico em relação ao carvalho francês. Finalmente, o conteúdo total de taninos elágicos de Q. humboldtii foi inferior ao dos carvalhos europeus e semelhante ao do carvalho americano (Q. alba). Nenhum dos taninos elágicos estudados apresentou diferenças significativas relativamente a Q. alba. Assim, a composição fenólica da madeira de Q. humboldtii assemelha-se mais à da madeira de Q. alba do que à de Q. sessiliflora.

Volatile composition and sensory characteristics of Carménère wines macerating with Colombian (Quercus humboldtii) oak chips compared to wines macerated with American (Q. alba) and European (Q. petraea) oak chips

“…In the first study on syringaldehyde and vanillin in untoasted and toasted oak, that toasted was found to show a similar vanillin concentration to Q. faginea, and a balanced syringaldehyde/vanillin relationship, a marker usually used to characterise oak wood quality . In the second study, the phenolic composition (ellagitannins and low molecular weight phenols) of green Q. humboldtii was characterised and compared to traditional oak, with the most abundant phenolic acids, aldehydes and ellagitannins being the same as in Q. alba and Q. petraea, and with a phenolic composition closer to American ones (Martínez-Gil et al, 2017). These two studies suggested that Q. humboldtii oak has potentially good properties for wine ageing, offering an alternative to traditional oak.…”

“…In addition, the Colombian oak staves were imported by Tonelería Nacional Chile LTDA after the usual semi-accelerated seasoning process, as normally done in cooperage for distilled beverages. The fact that this oak has a low ellagitannin content (Martínez-Gil et al, 2017) suggests that, after drying in the usual way for beverages like brandy or rum, it may have correct properties for wine ageing too. This semi-accelerated seasoning was carried out with steam in special rooms, where the temperature gradually increases, starting at 22 °C for the first few days of drying and Martínez-Gil, A. M., del Alamo-Sanza, M., Gutiérrez-Gamboa, G., .…”

“…Besides the study of the contact between oak and rums, we only know of two other studies on the composition of this oak when green, before and after toasting (González, Calderón & Cabeza, 2008, Martínez-Gil, Cadahía, Fernández de Simón, Gutiérrez-Gamboa, Nevares, & Del Álamo-Sanza, 2017. In the first study on syringaldehyde and vanillin in untoasted and toasted oak, that toasted was found to show a similar vanillin concentration to Q. faginea, and a balanced syringaldehyde/vanillin relationship, a marker usually used to characterise oak wood quality .…”

“…Nowadays these cooperages with over 50 years' experience in making barrels for distillates are trying to introduce them to the wine industry, guaranteeing the same quality as that of oak traditionally used for ageing wines. However, to our knowledge there is no information about the performance of Q. humboldtii in winemaking.Besides the study of the contact between oak and rums, we only know of two other studies on the composition of this oak when green, before and after toasting (González, Calderón & Cabeza, 2008, Martínez-Gil, Cadahía, Fernández de Simón, Gutiérrez-Gamboa, Nevares, & Del Álamo-Sanza, 2017. In the first study on syringaldehyde and vanillin in untoasted and toasted oak, that toasted was found to show a similar vanillin concentration to Q. faginea, and a balanced syringaldehyde/vanillin relationship, a marker usually used to characterise oak wood quality .…”

Bosque de roble o plantación de coníferas, ¿qué prefieren los líquenes epífitos?

“…Por su parte, como especies únicas de Quercus humboldtii se observa a Anzia leucobatoides (que corresponde a un nuevo registro para el país), Leptogium diaphanum y Sticta isidioimpresula y tres especies de Astrothelium que corresponden a especies propias de bosques conservados y denotan una preferencia por ambientes de baja luminosidad, pero que son tolerantes a la acides que la presencia de taninos le confiere a los robles (Martínez-Gil et al, 2017). Estos resultados son comparables con los estudios Wolf (1993a), que señalan entre 35 y 50 especies en las formaciones vegetales evaluadas y con las 41 especies de Graphidaceae sobre robles, identificadas por Ardila et al (2015).…”