Discrimination of aging wines with alternative oak products and micro-oxygenation by FTIR-ATR

The use of alternative oak wood products (AOP), such as chips, cubes and staves, among other, from different geographical origins is a common practice for wine aging, where the micro-oxygenation (MOX, adding small doses of oxygen constantly over time) is essential to obtain a final wine more stable in time and with similar characteristics of barrel-aged wine. The aim of this work was to identify if spectroscopic techniques allow to discriminate wines aged with alternative oak products (chips and staves) from different oak woods (American, French and Spanish) and a floating micro-oxygenation (20 µg·L−1) after 10 years of bottling and compared to those aged in barrels. The spectral information and analysis were performed in a FTIR-ATR, with 128 scans per spectrum at a spectral resolution of 8 cm-1 in the wavenumber range from 4,000 to 450 cm-1. Principal component analyses of spectral information were performed using the Unscrambler® X. The results indicate that with this technique it is possible to clearly separate the wines aged by the three systems (chips, staves and barrels) in the case of American oak. In the case of French oak, wines aged in chips were clearly differentiated from wines aged in staves with those aged in barrels between the two. It is also possible to clearly separate aged wines with different Spanish oak systems. The application of FTIR-ATR appears to be a powerful technique for discriminating the quality of wines aged by different AOPs and wood barrels from different geographical origins

Impact of long bottle aging (10 years) on volatile composition of red wines micro-oxygenated with oak alternatives

The adding of wood pieces together with small amounts of oxygen to simulate the processes for aging red wine in barrels is the most common alternative to oak barrels. The evolution of these wines aged with alternatives in bottle has not been examined in depth as they are considered to be for rapid consumption. This paper presents for the first time the evolution in bottle for 10 years of the same wine aged in oak barrels and subjected to diverse alternative aging processes using different woods. Wines subjected to this alternative have evolved after 10 years in the bottle in a similar way to those aged in barrels. Wines aged in barrels retain significantly higher levels of blue tonalities than those treated with chips + FMOX and the loss of compounds responsible for red is almost double in wines treated with alternatives than in those aged in barrels. Wines aged in barrels showed higher concentrations of cis- and trans-whiskylactones than those treated with alternative products. In both the cis/trans whisky lactone ratio has been around 2 in wines aged in French oak, and over 5 in wines aged in American oak. Adequate oxygen management during treatment with oak alternatives provides long-life wines.Work financed by Junta de Castilla y León (VA028U16), MINECO (AGL2014-54602-P), FEDER, Interreg España-Portugal Programme (Iberphenol). T.G.C. thanks MINECO for her contractPeer reviewe

Phenolic and volatile compounds in Quercus humboldtii Bonpl. wood: effect of toasting with respect to oaks traditionally used in cooperage

[Background] The most frequent renewal of barrels of different origins and species is a current trend, but this demand does not match the current availability of wood. An alternative could be the use of Quercus humboldtii wood. However, there is little information about its composition. Because of this, the aim was to study low‐molecular‐weight phenols (LMWP), ellagitannins and volatile compounds in untoasted and toasted Q. humboldtii oak, and compare these with the species traditionally used in cooperage: Q. petraea (French and Romanian) and Q. alba (American). [Results] The LMWPs in Q. humboldtii were comparable to those in Q. petraea and Q. alba. Ellagitannin composition in Q. humboldtii was similar to that in Q. alba. The toasting process improved volatile composition, mainly in Q. humboldtii, presenting the highest concentration of several volatile compounds. [Conclusion] The results indicate that Q. humboldtii could be considered suitable for aging wine, although it is necessary to continue the study of this wood species to confirm its potential use in oenologyThis work was financed by the European Regional Development Fund FEDER, Interreg Spain–Portugal Programme, under the framework of the project Iberphenol, POCTEP—Programa Operativo Cooperación Transfron, CONICYT, Fondecyt de Iniciación Grant No. 11150462, Chile, Ministerio de Economía y Competitividad, AGL2014‐ 54602P, Consejería de Educación, Junta de Castilla y León, VA028U16 and with the collaboration of Tonelería Nacional Ltda, Santiago de Chile. G.G.‐G. would like to acknowledge the financial support given by CONICYT through BCH/Doctorado (72170532)Peer reviewe

Method to estimate the medullar rays angle in pieces of wood based on tree-ring structure: application to planks of Quercus petraea

Producción CientíficaEstimating wood parameters employing non-destructive methods has been widely studied in recent years. The choice of wood used to build wine ageing barrels (cooperage) is strongly influenced by wood anatomy and specifically by the orientation of medullar rays among other aspects. In this article, a method based on the regularities of the tree-ring structure to estimate the medullar ray angle of the cross section of a piece of wood is proposed. This angle shows the direction of the best linear path to evaluate several tree-ring features and could be employed to automate tasks, such as introducing an analysis path or rotating the image prior to the analysis, which some dendro analysis methods require. A dataset of 26,992 synthetic images and 110 real oak wood images was used to validate the approach. The medullar ray angle of each image considered was measured manually and estimated using the method proposed here, which employs the fast Fourier transform (FFT) to take advantage of the tree-ring structure regularities and find the direction angle of the best linear path to evaluate several tree-ring features. The results obtained demonstrate a mean squared error of 0.29° and 8.19° and a mean absolute error of 0.19° and a 5.91° for the synthetic and oak wood images, respectively. These data suggest the suitability of the proposed method as part of an automated system to inspect and analyse the growth rings in oak wood planks

Effect of different ageing techniques on the polysaccharide and phenolic composition and sensorial characteristics of Chardonnay white wines fermented with different selected Saccharomyces Cerevisiae yeast strains

Producción CientíficaPolysaccharides, mainly mannoproteins, play an important role on technological and sensory quality of wines. These compounds are released to the wine during alcoholic fermentation and, thereafter, during yeast autolysis in the ageing process. The effect of the ageing on lees and other alternative ageing techniques were studied in Chardonnay Chilean white wines previously fermented with different Saccharomyces cerevisiae yeast strains (Zymaflore VL2 and Lalvin CY3079). The Lalvin CY3079 released higher amounts during alcoholic fermentation and during the first stages of the ageing than the Zymaflore VL2, which could produce a positive effect on the colour intensity of wines. Some statistically significant differences on phenolic families and sensory attributes were observed after alcoholic fermentation, during the ageing period and bottle storage, but this depended on the yeast strain used, the ageing technique applied and the period of ageing and bottle storage analysed.Comisión Nacional de Investigación Científica y Tecnológica (CONICYT-Chile). Proyecto FONDECYT Postdoctoral Nº 313048