Macrowine 2021
IVES 9 IVES Conference Series 9 Reduction of herbaceous aromas by wine lactic acid bacteria mediated degradation of volatile aldehydes

Reduction of herbaceous aromas by wine lactic acid bacteria mediated degradation of volatile aldehydes

Abstract

Consumers typically prefer wines with floral and fruity aromas over those presenting green-pepper, vegetal or herbaceous notes. Pyrazines have been identified as causatives for herbaceous notes in wines, especially Bordeaux reds. However, pyrazines are not universally responsible for herbaceousness, and several other wine volatile compounds are known to produce distinct vegetal/herbaceous aromas in wines. Specifically, volatile aldehydes elicit sensations of herbaceousness or grassiness and have been described in wines well above their perception thresholds. Acetaldehyde is quantitatively the most important aldehyde and formed by yeast metabolism or through the auto-oxidation of ethanol during and after fermentations. Its grassy-green aroma typically is prevented by addition of SO2 that strongly binds to acetaldehyde hence masking its aroma. Hetero- and homofermentative wine lactic acid bacteria are responsible for the secondary malolactic fermentation in most red and some white wines and can degrade acetaldehyde. During malolactic fermentation, wine lactic acid bacteria are capable of reducing acetaldehyde levels significantly (~90%). Two reaction pathways were previously described by our group, the chemical reduction of acetaldehyde to ethanol by alcohol dehydrogenase (ADH), or its oxidation to acetic acid by aldehyde dehydrogenase (Al-DH). ADH and Al-DH are known to have a broad substrate specificity. Hence, it is possible that wine lactic acid bacteria may be able to degrade other volatile aldehydes that are known to contribute to herbaceousness in wines. Hexanal, methional, 2-methylbutanal, 3-methylbutanal, 2-methylpropanal, E-2-nonenal and phenyl-acetaldehyde are aldehydes and powerful herbaceous aroma compounds with odour thresholds between 0.5 and 16 µg/l. The odour thresholds of their corresponding alcohols are 100 to 14’000 times higher. Thus, chemical reduction of these aldehydes to the corresponding alcohols by wine lactic acid bacteria may lead to a reduction of herbaceous notes. Within the scope of this investigation, highly concentrated solutions of resting cells of several heterofermentative and facultative homofermentative wine lactic acid bacteria of the genera Oenococcus and Lactobacillus were tested for their ability to degrade these volatile aldehydes. A careful incubation and sample-taking protocol was applied in order to prevent sample evaporation. The analysis of volatile aldehydes was performed by liquid-liquid micro-extraction followed by GC-MS analysis. It could be demonstrated that all bacteria were able to degrade all volatile aldehydes efficiently. Within 50 minutes, an average of 95% of the initial aldehyde concentration was degraded with minima and maxima of 63 and 100%, respectively. The results suggest that wine lactic acid bacteria may be able to degrade volatile aldehydes during malolactic fermentation thus reducing their sensory impact and increasing sensory perception of compounds with fruity character.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Ramon Mira de Orduna*, Alexandra Le Boursier, Marilyn Cléroux, Tatevik Gabrielyan

*HES-SO

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Effect of concentration and competition between different fungicide residues on the adsorption efficiency of activated vegetal fibres for treatment of wine

Vineyards are strongly exposed to fungal diseases, attacks from insects and competition with weeds. Most treatments used on grape vines contain synthetic active substances, which may be transferred to the wine. Such pesticides have a negative image because many active substances are potential health hazards. A specific oenological treatment allowing the reduction of pesticide residues in wine based on activated vegetable fibres (AVF) is under examination by the International Organisation for Vine and Wine. This technique works efficiently and alters the wine only little (Lempereur et al. 2014).

Capture depletion of grapevine DNA: an approach to advance the study of microbial community in wine

The use of next-generation sequencing (NGS) has helped understand microbial genetics in oenology. Current studies mainly focus on barcoded amplicon NGS but not shotgun sequencing, which is useful for functional analyses. Since the high percentage of grapevine DNA conceals the microbial DNA in must, the majority of sequencing data is wasted in bioinformatic analyses. Here we present capture depletion of grapevine whole genome DNA.

Fingerprinting the origin of rosé wines with a new high throughput polyphenomics method

Wine is a widely consumed alcoholic beverage with a high commercial value. More specifically, the worldwide consumption of rosé wine has increased by 20% since 2002[1]. But because of its high commercial value, it can become a subject of fraud, and authenticity control is necessarily required. More than one hundred polyphenols have been recently quantified in various rosé wines [2]. They are key components defining color, taste and quality of wines. Their amount and composition depend on many different factors such as grape variety, winemaking and age of the wine. In this study, the influence of geographic origin of some rosé French wines was investigated. An original and very fast UPLC-QTOF-MS method was developed and used to predict the geographic origin authenticity of rosé wines.

Novel analytical technologies for wine fingerprinting in and beyond the laboratory

For characterization, sensory designing and authentication rapid analytical technologies have become available. Some, like Proton Transfer Reaction Mass Spectrometry allow a rapid spectrum of the volatile compounds of wines. Combined with chemometrics wines can be characterized. The same approach can be used to calculate the results of virtual mixtures and allow formulation of constant quality blends. Other new techniques and portable devices based on spectroscopy allow measurements on production sites and in grocery stores, even for the smart consumer. We will present some examples of the application of these techniques for authentication of wines, both in the laboratory and on site.

Comparison of fortified, sfursat and passito winemaking techniques for the enhancement of the oenological potential of the black grape cultivar Moscato nero d’Acqui (Vitis vinifera L.)

One of the key factors of the economical development of viticulture and wine industry in specific limited areas is the exploitation of ancient, local grape varieties. Therefore, in recent years the growing interest to rediscover minor varieties, previously cultivated, has promoted many studies. With this regard, the focus of this study was the Vitis vinifera L. cultivar Moscato nero d’Acqui, nowadays found only in old vineyards in the Acqui zone (North-West Italy). In particular, the aims of this work were: i) to investigate secondary metabolites profile of the grapes, and ii) to evaluate the attitude to the production of special wines.