IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Possible Reduction Method Of Volatile Acid Content And Polyphenols Of Tokaj Aszú Wines With The Aid Of Citosan Bactericid Wine-Treatments

Possible Reduction Method Of Volatile Acid Content And Polyphenols Of Tokaj Aszú Wines With The Aid Of Citosan Bactericid Wine-Treatments

Abstract

The historical Tokaj region in northeast Hungary is a UNESCO World Heritage region since 2002 owning 5.500 ha vineyards. Produced from „noble rot” grapes, Tokaji Aszú is known as one of the oldest botrytized wines all over the world. Special microclimatic conditions (due to Bodrog and Tisza rivers, Indian summer), soil circumstances (clay, loess on volcanic bedrock) and grape-varieties (Furmint, Hárslevelű) of Tokaj-region offer favourable parameters to the formation of noble rot caused by Botrytis cinerea. The special metabolic activity of Botrytis results in noble rot grapes called “aszú” berries. The grapes undergo complex chemical modifications as the joint result of the enzymatic activity of Botrytis and the physical process of concentration.
The wine-making method of Tokaj wine specialities often gives a serious microbiological challenge to winemakers. Increasing the volatile acid content of wines is becoming more frequent, one of the technological ways to keep them lower is the use of special chitosan products, which have an inhibitory and cid effect on acetic and lactic acid bacteria.
The BactilessTM® preparation distributed by Kokoferm Ltd. and EnartisSTAB Micro by Esseco s.r.l (Divisione Enartis) are GMO and allergen-free biopolymer of Aspergillus niger, what can reduce the germ count of live acetic and lactic acid bacteria.
Phenolic compounds are responsible for the oxidation of wines, and their presence is essential for developing the character of the wine. During grape proccessing procedure, it is very important to pay particular attention to polyphenols releasing from the berry skin and seed coat because in contact with a small amount of oxygen, it can be formed with oxide compounds accompanied by masking fruitiness, hindering transformation of aroma-carrying precursors. In the case of working with noble rotted berries, an increased polyphenol content can be found endangering taste harmony, that is why every treatment with reducing polyphenols effect may be useful.
In this work, three Tokaj aszú wine types were tested with Bactiless and EnartisSTAB materials. The number of germs of lactic acid bacteria was significantly reduced by the treatments, it was no longer detectable at the higher application dose, it was also effective against acetic acid bacteria, and their amount decreased by an order of magnitude. During the treatment period, the level of volatile acid did not increase, and the amount of undesirable odor metabolites also decreased appreciably. Despite the fact, that the primary function of active chitosans is antimicrobial control, the polyphenol content has also been reduced by 5-8%.

DOI:

Publication date: June 24, 2022

Issue: IVAS 2022

Type: Poster

Authors

Bene Zsuzsanna1

1University of Tokaj, Lórántffy Institute, Department of Viticulture and Oenology

Contact the author

Keywords

acetic acid and lactic acid bacteria, chitosan, polyphenols, Tokaj

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

Stabulation (lees stirring) in must as a method for aroma intensification: A comparison with skin contact and a classical version of Traminer and Sauvignon blanc in Austria

In the course of this study, stabilisation (lees stirring in unclarified must) with skin contact and classic white wine vinification were compared for the Sauvignon blanc and Traminer varieties in Austria. The test wines were analysed for the volatile substances esters, free monoterpenes and fruity thiols

EMERGENCE OF INORGANIC PHOSPHONATE RESIDUES IN GRAPEVINE PLANT PARTS, BERRIES AND WINES FROM SOURCES OTHER THAN FOLIAR SPRAYING

Inorganic phosphonates are known to effectively support the control of grapevine downy mildew in vi- ticulture. Their application helps the plant to induce an earlier and more effective pathogen defense. However, inorganic phosphonates have been banned in organic viticulture due to their classification as plant protection products since October 2013. Despite the ban, phosphonate has been recently detected in organic wines.

Grape pomace, an active ingredient at the intestinal level: Updated evidence

Grape pomace (GP) is a winemaking by-product particularly rich in (poly)phenols and dietary fiber, which are the main active compounds responsible for its health-promoting effects. GP-derived products have been proposed to manage cardiovascular risk factors, including endothelial dysfunction, inflammation, hypertension, hyperglycemia, and obesity. Studies on the potential impact of GP on gut health are much more recent. However, it is suggested that, to some extent, this activity of GP as a cardiometabolic health-promoting ingredient would begin in the gastrointestinal tract as GP components (i.e., (poly)phenols and fiber) undergo extensive catabolism, mainly by the action of the intestinal microbiota, that gives rise to low-molecular-weight bioactive compounds that can be absorbed and utilized by the body.

The use of elicitors in viticulture: a tool to obtain highly colored wines with a reduce alcohol content?

Climate change is causing a gap between the technological and phenolic maturity of grapes, resulting in wines with high alcohol content and low polyphenol concentration. Another phenomenon associated with high temperatures and whose effect is more pronounced if the harvest is delayed is the decrease in the acidity of the grapes, mainly in malic acid, and an increase in pH caused by the accumulation of potassium derived from the increase in temperature. Therefore, climate change and the effects it causes on the vine leads to unbalanced wines, with high alcohol content and lack of color, with green tannins, astringency and excessively low acidity if not corrected.

“Terroir” studies in the Côtes du Rhône controlled appellation: from zoning to application

This work gives a summary of the most important programmes about viticultural « terroirs », developed on the « Côtes du Rhône » controlled appellation area for about twenty years.