Macrowine 2021
IVES 9 IVES Conference Series 9 The impact of acetaldehyde on phenolic evolution of a free-SO2 red wine

The impact of acetaldehyde on phenolic evolution of a free-SO2 red wine

Abstract

AIMS: Some wine producers, in good years, can produce free-SO2 red wines and decide to add the minimum amount of sulphur dioxide only at bottling. To manage this addition, it is important to know the oxidative history of the wine. Acetaldehyde, the main wine oxidation product, is a powerful electrophile that reacts with numerous wine compounds giving desired products as the stable red polymeric pigments and the less astringent tannins but, also negative off-flavours. Although all these reactions are well known, the border between those increasing wine longevity and those decrementing wine quality is difficult to determine. This study has the aim to investigate the kinetics of consumption of acetaldehyde in red wines to give information useful for the further management of sulphur dioxide.

METHODS: Free-SO2 red wines were spiked with increasing levels of acetaldehyde (from 0 to 190 mg/L) and analysed over time. Chromatic properties and main phenolic classes were analysed by conventional spectrophotometric methods. Small phenolics, polymeric pigments (PP) and polymeric tannins (PT) were detected by HPLC, MS and NMR analysis.  Reactivity of tannins towards BSA and saliva was also determined (1-2-3).

RESULTS: Already two hours after the addition of acetaldehyde the 50% was consumed in reactions with phenolic compounds and the consumption increased over time. Also when a great excess of aldehyde was added (190 mg/L) and after one year of aging a loss of 75% of the initial value was detected. The first compounds that were consumed in reactions with acetaldehyde were anthocyanins and flavanols and a contemporary increase of polymeric pigments and tannins occurred. BSA and saliva reactive tannins increased over time when high concentration of acetaldehyde were added.

CONCLUSIONS

For a correct management of sulphur dioxide when bottling a free-SO2 red wine the content of acetaldehyde and phenolic strong reactants (anthocyanins and flavanols) should be determined to limit or favour further acetaldehyde reactions

DOI:

Publication date: September 14, 2021

Issue: Macrowine 2021

Type: Article

Authors

Francesca Coppola

Department of Agricultural Sciences, Division of Vine and Wine Sciences, University of Naples Federico II, Avellino, (Italy),Luigi Picariello, Martino Forino,  Luigi Moio, Angelita Gambuti Department of Agricultural Sciences, Division of Vine and Wine Sciences, University of Naples Federico II, Avellino, (Italy)

Contact the author

Keywords

wine longevity, polyphenols

Citation

Related articles…

Rapid damage assessment and grapevine recovery after fire

There is increasing scientific consensus that climate changeis the underlying cause of the prolonged dry and hot conditions that have increased the risk of extreme fire weather in many countries around the world. In December 2019, a bushfire event occurred in the Adelaide Hills, South Australia where 25,000 hectares were burnt and in vineyards and surrounding areas various degrees of scorching and infrastructure damage occurred. The ability to coordinate and plan recovery after a fire event relies on robust and timely data. The current practice for measuring the scale and distribution of fire damage is to walk or drive the vineyard and score individual vines based on visual observation. The process is time consuming, subjective, or semi-quantitative at best. After the December 2019 fires, it took many months to access properties and estimate the area of vineyard damaged. This study compares the rapid assessment and mapping of fire damage using high-resolution satellite imagery with more traditional ground based measures. Satellite imagery tracking vineyard recovery in the season following the bushfire is being correlated to field assessments of vineyard productivity such as canopy health and development, fertility and carbohydrate storage. Canopy health in the seasons following the fires correlated to the severity of the initial fire damage. Severely damaged vines had reduced canopy growth, were infertile or had very low fertility as well as lower carbohydrate levels in buds and canes during dormancy, which reduced productivity in the seasons following the bushfire event. In contrast, vines that received minor damage were able to recover within 1-2 years. Tools that rapidly and affordably capture the extent and severity of damage over large vineyard area will allow producers, government and industry bodies to manage decisions in relation to fire recovery planning, coordination and delivery, improving the efficiency and effectiveness of their response.

Development of spectral indices to monitoring non-destructive of ripeness for water stressed grapevine (Vitis vinifera L.) using contour map optimization

Accurate and non-destructive monitoring of grape ripening is essential for optimising harvest decisions, particularly under water stress conditions.

Topographic modeling with GIS at Serra Gaúcha, Brazil: elements to study viticultural terroir

Brazil is historically known at the international wine market as an importer, eventhough in the last decades there was an increase in quantity and quality of the internal production. Nowadays, about 40% of fine wines comsuption of the country are national ones. The main production region is called Serra Gaúcha, where the natural conditions are heterogeneous and viticulture is develloped in small properties, mainly done by the owners family.

Use of sensors/biosensors for detection of food safety parameters in wine

The implementation of food safety assurance systems in wineries involves ensuring that the wines produced do not pose a risk to consumer health and are therefore free from harmful substances, such as those that may be incorporated during the production process (pesticides, additives, etc.), allergens or mycotoxins.

Some applications come from a method to concentrate proteins

All techniques usually used to assay proteins was not reliable in vegetable extract due to interferences with the components included in extracts like polyphenols, tanins, pectines, aromatics compounds. Absorbance at 280nm, Kjeldhal assay, Biuret and Lowry methods, Acid Bicinchonique technique and Bradford assay give the results depending on the composition of extract, on the presence or not of detergent and on the raw material (Marchal, 1995). Another difficulty in these extracts for the quantification of proteins comes from the large amount of water included in vegetable and the low concentration of proteins. Thus in red wines, proteins are usually not taken into account due to their low concentration (typically below 10 mgL-1) and to the presence of anthocyanis and polyphenols.