Chemo-sensory approach for the identification of chemical compounds driving green character in red wines

Abstract

The present work seeks to define the "green character" of red wines and characterise the groups of molecules potentially involved in that perception. Fifty-four wines were screened by wine experts for different levels of green character. Six different phenolic fractions were obtained by liquid chromatography (LC) and further submitted to sensory and chemical characterisation. The volatile fraction was screened by semipreparative LC, Gas Chromatography-Olfactometry (GC-O) and quantitative analysis. The green character was linked to vegetal aroma, astringency, green and dry tannins according to experts of the Somontano region. Non-volatile fractions containing tannins with mean degree of polymerisation of ten and smaller anthocyanin-derivative pigments (<tetramers) imparted astringency-related sensations such as dryness and stickiness, respectively. No specific aroma compounds were identified in the GC-O study of green wines, however the wines contained significantly higher levels of fusel alcohols. The interaction between isoamyl alcohol and the anthocyanin-derivative fraction and/or tannins is suggested to be involved in the formation of green character in red wines.

Access to wine experts' long-term memory to decipher an ill-defined sensory concept: the case of green red wine

“…The relatively low frequency of citation of terms is related to the nature of the approach because participants were asked to describe the last green wine they tasted, and thus to exemplify the category of green wines, rather than searching for the description of a prototype, which would have led to higher frequencies of citations. The multidimensionality observed for the green wine concept in the present research coincides with the results observed in a study carried out by experts from DO Somontano which involved the tasting of 54 red wines (Sáenz-Navajas et al, 2018). In that article, "green character" of wines was scored and significantly correlated with the aroma term "vegetal aroma", the trigeminal term "astringency" and with a term linked to wine components such as (dry and green) "tannins".…”

“…In relation to this last type of language, it is a challenge to unequivocally interpret some concepts normally employed by experts when describing wines. Some examples of difficult to interpret wine concepts are: "minerality" (Rodrigues et al, 2015), "complexity" (Parr et al, 2011), "bouquet" (Picard et al, 2015) and "green" (Sáenz-Navajas et al, 2018) among others. Experts accumulate an important number of tasting experiences and identify common sensory patterns that are verbalised by using this type of language.…”

Volatile and phenolic composition of monovarietal red wines of Valpolicella appellations

“…3-methyl-1-butanol and 2-phenylethanol showed the highest concentrations in all studied wines, their concentrations always exceeding the odour threshold (Supplementary S.4.). However, De-La- Fuente-Blanco et al (2016) showed that the aroma contribution of methionol and 2-phenylethanol to model wines was insignificant, even at concentrations well above the odour threshold; whereas 3-methyl-1-butanol was reported to contribute to the green character of wine (Sáenz-Navajas et al, 2018). The highest concentration of total higher alcohols was observed in Sangiovese and the lowest in Rondinella and Cabernet-Sauvignon.…”

Preliminary sensory characterisation of the diverse astringency of single cultivar Italian red wines and correlation of sub‐qualities with chemical composition

“…Indeed, in a chemosensory study aimed to characterise the fractions driving different mouthfeel properties in red wines, only the category unripe was not included in the final list of terms generated to describe the in-mouth sensations elicited during the tasting of the different odourless fractions (Sáenz-Navajas et al 2017). The same authors tried to understand the involvement of volatile organic compounds modulating the perception of the green character of red wine astringency (Sáenz-Navajas et al 2018). No specific aroma compounds were identified but a high concentration of fusel alcohols was observed and the involvement of interactions between isoamyl alcohol and anthocyanin-derivative fractions and/or tannin was suggested.…”