Fermentation Products, Degradation Parameters, (Poly)Phenols And Potassium Content In Tokaji Aszú Winemaking

Abstract

The historic Tokaj Wine Region in northeast Hungary, a UNESCO World Heritage region since 2002, encompasses 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 conditions (clay, loess on volcanic bedrock) and grape varieties (Furmint, Hárslevelű) of the Tokaj Wine Region offer favourable parameters for 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.
In my work, the presence of fermentation products, degradation parameters, (poly-)phenols and potassium were studied in raw Aszú wines of the year of 2020.
The determination of the chemical composition was measured using NMR technique and Thermo Fischer Gallery spectroscope. The data analysis is performed at Bruker BioSpin GmbH according to testing method AA-72-02-06 (Wine-Profiling 4.0.4), and at TFG the results are calculated automatically by the analyzer from sample responses and calibration curve equation.
The main results to summarize are shown in Table 1.
Parameters/Average value range normal sweet white wine/Measured value range in raw Aszú wines
gluconic acid <400 mg/L 600 – 900 mg/L
acetaldehyde 10-15 mg/L 45 – 80 mg/L
galacturonic acid 160-350 mg/L 600 – 800 mg/L
succinic acid 50-500 mg/L 700 – 900 mg/L
glycerol 4.6-12,7 g/L 17 – 32 g/L
shikimic acid <20 mg/L 23 – 47 mg/L
trigonelline <10 mg/L 12 – 15 mg/L
total polyphenols 150-300 mg/L 440 – 490 mg/L
potassium <1000 mg/L 800 – 1500 mg/L

To sum up, in the case of the examined parameters, there are significant differences in the chemical composition between conventional sweet white wines and Aszú wines. These characteristics might be numerical indicators of the specific aroma composition of noble rot natural sweet wines; they might be suitable for verifying the origin of wines using a mathematical model based on processing the special properties of different vintages.