Macrowine 2021
IVES 9 IVES Conference Series 9 Evaluating South African Chenin blanc wine styles using an LC-MS screening method

Evaluating South African Chenin blanc wine styles using an LC-MS screening method

Abstract

Sorting Chenin blanc is one of the most important white wine cultivars in South Africa. It has received a lot of attention and accolades in the past years and more research than ever is dedicated to this versatile cultivar. According to the Chenin blanc association of South Africa, there are three recognized dry wine styles, Fresh and Fruity (FF), Rich and Ripe Unwooded (RRU), and Rich and Ripe Wooded (RRW). They are traditionally established with the aid of expert sensory evaluation, but the cost and the (subjective) human factor are aspects to be taken into account. A more objective and possibly robust way of assessing and attributing these styles can be the use of chemical analysis. A sample set of 18 wines were subjected to sensory evaluation by 30 experts using first free and then directed sorting tasks, taking into account both aroma and taste. The data has been analysed using DISTATIS to assess individual differences between samples as well as to build a multivariate map of the data. The same samples were also analysed by LC-MS using a screening method developed for this purpose. The data generated was analysed using MarkerLynx XS (Waters Corporation), an application manager that performs 3D peak integration, data set alignment and incorporates multivariate statistical tools. The software is directly integrated with Umetrics SIMCA-P and the PCA algorithm is directly applied to the processed data sets. The sensory and chemistry data sets were treated separately and groupings of samples around the predefined styles were found for both sets. Results indicate that even though the traditional evaluation of Chenin blanc styles has its merits, a more objective way of attributing the style is also possible with the help of chemical analysis coupled with integrated statistical tools.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Astrid Buica*, Christine Wilson, Jeanne Brand, Marietjie Stander

*Stellenbosch University

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Red wine substituted esters involved in fruity aromatic expression: an enantiomeric approach to understand their sensory impact and their pathway formation

Among red wines ethyl esters, those from short hydroxylated and branched-chain aliphatic acids constitute a family with a particular behavior and sensory importance. They have been previously discussed in the literature [1] and recent studies have established that some of them were strongly involved in of red wines’ fruity aroma [2]. As some among them have an asymmetrical carbon atom, it seemed important to separate their different enantiomers to obtain an accurate assessment of their organoleptic impact. Three chiral esters have been identified, presenting alkyl and/or hydroxyle substituants: ethyl 2-hydroxy-4-methylpentanoate, ethyl 2-methylbutanoate, and ethyl 3-hydroxybutanoate.

The moment of preharvest elicitor application influence its final effect on winegrapes quality

Phenolic compounds are secondary metabolites of grapes. Plants produce a wide variety of this type of metabolites through diverse biosynthesis pathways and their production is sometimes a response to external stimuli, either environmental or biotic stresses. Some of them may act as chemical defenses against pathogens or herbivores and their synthesis is increased when the attack exists. However, it is remarkable that the synthesis of these interesting compounds can be activated even when the stimulus is not present, with the use of elicitors. These are substances that when applied exogenously trigger the biosynthetic pathways conducting to the synthesis of these defense compounds.

Ageing of sweet wines: oxygen evolution according to bung and barrel type

Barrel ageing is a crucial step in the wine process because it allows many changes to the wine as enrichment, colour stabilization, clarification and also a slow oxygenation. Effects of the oak barrel have to be known to prevent oxidation of the wine. The type of bung used during ageing is also a parameter to consider. Ageing sweet wines in barrel is a real challenge. These wines may need some oxygen at the beginning of ageing but they should be protected at the end of their maturation, to avoid oxidation.

Simultaneous monitoring of dissolved CO2 and collar from Rosé sparkling wine glasses: the impact of yeast macromolecules

Champagne or sparkling wines elaborated through the same traditional method, which consists in two major yeast-fermented steps, typically hold about 10 to 12 g/L of dissolved CO2 after the second fermentation in a closed bottle. Hundreds of molecules and macromolecules originating from grape and yeast cohabit with dissolved CO2; they are essential compounds contributing to many organoleptic characteristics (effervescence, foam, aroma, taste, colour…). Indeed, the second alcoholic fermentation and the maturation on lees (which may last from 12 months up to several years) both induce various quantitative and qualitative changes in the wine through the action of yeast, as listed hereafter: development of aromas during aging on lees, release of nitrogen compounds during autolysis and release of macromolecules (polysaccharides, lipids, nucleic acids) in wine.

Microbial life in the grapevine: what can we expect from the leaf microbiome?

The above-ground parts of plants, which constitute the phyllosphere, have long been considered devoid of bacteria and fungi, at least in their internal tissues and microbial presence there was long considered a sign of disease. However, recent studies have shown that plants harbour complex bacterial communities, the so-called “microbiome”[1]. We are only beginning to unravel the origin of these bacterial plant inhabitants, their community structure and their roles, which in analogy to the gut microbiome, are likely to be of essential nature. Among their multifaceted metabolic possibilities, bacteria have been recently demonstrated to emit a wide range of volatile organic compounds (VOCs), which can greatly impact the growth and development of both the plant and its disease-causing agents.