Validation of a rapid conductimetric test for the measurement of wine tartaric stability

Research progress of tartaric acid stabilization on wine characteristics

Tartaric acid is one of the characteristic acids in wine, playing a crucial role in wine characteristics. However, superabundant tartaric acid will form insoluble salts and precipitate in the form of crystals, affecting consumers' purchasing appetite. Therefore, tartaric stability is also one of the important indices for controlling the wine quality. At present, the main processing methods for tartaric stability include cold stabilization, ion exchange treatment, electrodialysis and the addition of exogenous components (gum arabic, metatartaric acid, carboxymethyl cellulose, mannoprotein and potassium polyaspartate). This review summarizes and analyzes the origin of tartaric acid in wine, factors influencing the tartaric stability, detection methods, treatments for tartaric stabilization, and the effects of these methods on the sensory quality of wine. Comparing the effects of these methods on wine quality can provide a basis for the further study of tartaric stabilization methods in order to select an appropriate tartaric stabilization method.

The influence of agricultural practices in vineyards on the predisposition of wines to crystalline turbidities

On the example of the Cabernet-Sauvignon variety, the dependence of the physicochemical parameters of grape must and the wine materials produced from it, on the formation of the grape bush (Cordon or Guyot) and green operations (chasing the upper leaves, pinching, removing stepsons) is shown. The influence of the listed factors on the predisposition of wines to crystalline turbidities is shown.

Use of potassium polyaspartate for stabilization of potassium bitartrate in wines: influence on colloidal stability and interactions with other additives and enological practices

The research was aimed at verifying the efficacy of potassium polyaspartate (KPA), added at bottling, for prevention of the precipitation of potassium bitartrate (KHT). The stability of KHT was determined with the mini-contact test and the cold test. The effect of KPA on the colloidal stability of white and red wines was also studied. Turbidity, color, and total anthocyanins and flavonoids (red wines only) were monitored. In the first experiment, the stabilizing effect of KPA added at bottling, with or without Arabic gum, tannins, and filtration (0.45 µm cut-off), was studied in comparison with metatartaric acid (MTA). KPA proved to have good stabilizing efficacy for prevention of KHT precipitation and maintained its effect in all trials after 1 year of bottle aging. On the contrary, all the trials with MTA became unstable after 6 months. Moreover, KPA did not modify wine turbidity and color. The filtration (0.45 µm cut-off) did not reduce its stabilizing efficacy. In the second experiment, the effect of KPA added to a white and a red wine, respectively clarified with casein and gelatin or vegetal protein and/or bentonite, was studied. KPA did not cause any increase in turbidity or appreciable changes in the color of the white wines of the different trials. A preliminary treatment with bentonite can prevent the possible formation of haze in red wines after the addition of KPA. PRACTICAL APPLICATION: KPA prevented the precipitation of KHT in unstable white and red wines. The stabilizing effect persisted after 1 year of bottle aging. The oenologist does not need to adopt special prescriptions when using KPA in combination with Arabic gum or tannins in prebottling operations. A treatment with bentonite prevented the appearance of turbidity in red wines after the addition of KPA.

Effect of the Atmospheric Pressure Cold Plasma Treatment on Tempranillo Red Wine Quality in Batch and Flow Systems

The demand for chemical-free beverages is posing a challenge to the wine industry to provide safe and healthy products with low concentrations of chemical preservatives. The development of new technologies, such as Atmospheric Pressure Cold Plasma (APCP), offers the wine industry the opportunity to contribute to this continuous improvement. The purpose of this research is to evaluate the effect of Argon APCP treatment, applied in both batch and flow systems, on Tempranillo red wine quality. Batch treatments of 100 mL were applied with two powers (60 and 90 W) at four periods (1, 3, 5, and 10 min). For flowing devices, 750 mL of wine with a flow of 1.2 and 2.4 L/min were treated at 60 and 90 W for 25 min and was sampled every 5 min. Treatments in batch resulted in wines with greater color intensity, lower tonality, and higher content in total phenolic compounds and anthocyanins, so that they were favorable for wine quality. Among the batch treatments, the one with the lowest power was the most favorable. Flow continuous treatments, despite being more appropriate to implement in wineries, neither led to significant improvements in the chromatic and phenolic wine properties nor caused wine spoilage.