Terroir 2004 banner
IVES 9 IVES Conference Series 9 Analytical and Chemometric Investigation of Phenolic Content of South African Red Wines

Analytical and Chemometric Investigation of Phenolic Content of South African Red Wines

Abstract

Phenolic compounds have been the focus of a lot of research in recent years for their important contribution to sensory characteristics of wine, their beneficial health effects, as well as the possibility they offer of characterising wines. In this contribution, a method is developed that allows the direct injection of wine samples followed by liquid chromatography-diode array-electrospray ionisation-ion trap mass spectroscopy (MS) for the quantitative and qualitative analysis of a wide range of non-coloured phenolics. Diode array detection was found to be more suitable for quantitative purposes, while on-line UV spectra in combination with mass spectra greatly facilitate the identification of phenolics. Although MS detection was characterised by relatively poor sensitivity (full scan mode) and linear response, this form of detection proved to be an exceedingly powerful identification tool, allowing identification of 20 non-standard compounds in wine. These include procyanidins, epigallocatechin, prodelphinidins (only the second time these compounds are identified in wine), tartaric acid esters of p-coumaric acid and caffeic acid, 3 resveratrol derivatives, myricetin and flavonol-glucosides. It is concluded LC-UV-MS currently represents the state-of-the art in analysis methods for wine polyphenols, combining quantitative and identification capabilities.
The LC-diode array method was subsequently used to quantify 16 phenolic compounds in 55 South African red wines. Values are compared to those reported in the literature for these compounds in wines from other countries. These data were used together with chemometric methods for the characterisation of these wines according to variety. Discriminant analysis allowed a 100% correct recognition of the 5 cultivars studied, independent of the vintage or geographical origin, based on non-coloured phenolic content.

Download the PDF

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

A. de Villiers (1), A. Crouch (1), Th. Heidemann (1), P. Majek (2), P. Sandra (1)

(1) University of Stellenbosch, Department of Chemistry, CENSSUS, Private Bag X1, Matieland 7602, South Africa
(2) Slovak University of Technology, Department of Analytical Chemistry, 812 37 Bratislava 1, Slovak Republic

Contact the author

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

Water relations of woody perennial plant species

Field irrigation experiments were performed on young « Nonpareil » almond trees, mature « Bartlett » pear trees and mature « Pinot Noir » grapevines, to determine the relation of a number of alternative measures of plant water status (predawn and midday stem and leaf water potential), to a number of indices of plant physiological activity (leaf conductance, vegetative growth and fruit growth and composition).

Read More

Defining the mechanisms and impact of winemaking treatments on tannin and polysaccharides in red wine: recent progress in creating diverse styles

Tannin and polysaccharide concentration and composition is important in defining the texture of red wines, but can vary due to factors such as cultivar, region, grape ripeness, viticultural practices and winemaking techniques. However, the concentration and composition of these macromolecules is dependent not only on grape tannin and polysaccharide concentration and composition, but also their extractability and, in the case of polysaccharides, their formation by yeast. Through studies into the influence of grape maturity, winemaking and sensory impacts of red grape polysaccharides, seed and skin tannins, recent research in our laboratory has shown that the processes involved in the extraction of these macromolecules from grapes and their retention in wine are very complex.

Read More

Can soil water content be used as a predictor of predawn leaf water potential for deficit irrigation scheduling? A case study at Alentejo wine region

Water and heat stress impose new challenges to irrigation management in the Mediterranean areas. This reality has a major impact on the vineyard ecosystem, particularly on the scarce water resources of the Alentejo region (South Portugal). To mitigate this problem, irrigation management should focus on optimizing yield and fruit quality per volume of water applied. This work aims to discuss the use of predawn leaf water potential and soil water status relationships as a decision tool for irrigation management taking as basis data from a field trial where two deficit irrigation strategies were compared.

Read More

Study of cross-modal interactions through sensory and chemical characteristics of italian red wines

This work aimed at investigating red wine olfactory–oral cross-modal interactions, and at testing their impact on the correlations between sensory and chemical variables. Seventy-four Italian red whole wines (WWs) from 10 varieties, and corresponding deodorized wines (DWs), were evaluated by sensory descriptive assessment.

Read More

Impact assessment of the reverse osmosis technique in wine alcohol management

Wine authenticity and composition can be influenced by a range of membrane separation processes as reverse osmosis. In the context of climate change, the natural trend is to obtain wines with higher alcoholic concentration when classical winemaking methods are employed, and this may induce alteration of typicity of wines by masking the olfactory and taste properties. This study aimed to evaluate the influence of reverse osmosis techniques used for decrease of ethanol content on the stable isotopic ratios as markers for wine authenticity characteristics.

Read More