BIO Web Conf.
Volume 15, 201942nd World Congress of Vine and Wine
|Number of page(s)||10|
|Published online||23 October 2019|
Effect of certain treatments to prevent or partially reverse the pinking phenomenon in susceptible white wines
University of Agronomic Sciences and Veterinary Medicine of Bucharest, Faculty of Horticulture, Department of Bioengineering of Horti-Viticultural Systems, 59 Marasti Ave., Sector 1, 011464 Bucharest, Romania
Pinking is a phenomenon occurring in certain white wines produced under highly reductive conditions which occasionally develop a pink colouration when suddenly exposed to air. The pink colouration gives the impression of wine being stained with red grape pigments, but in fact the phenomenon is a transformation in the presence of oxygen of some specific phenolic compounds found in the susceptible varieties. In our experiments two white wines based on Sauvignon blanc and Chardonnay, respectively, were found to have a high potential toward pinking. This study evaluates the potential of certain treatments to prevent the development of pinking or to partially reverse it after occurrence. Treatments tested involved the addition of 20 to 40 mg/l ascorbic acid or 5 to 30 mg/l of catechinic tannin prior to bottling. Both types of treatments had the potential to prevent pinking, irrespective of dosage used, as long as a normal concentration of free SO2 (above 0.8 mg/l molecular SO2) was maintained in the wines. Other treatments tested for bottled wines already developing a pink shade were the exposure of the bottle to UV light or the keeping in complete darkness, respectively. In the absence of any other pinking preventive measure both treatments proved to have a certain effect upon reversing the phenomenon. The UV light treatment shows more potential to reverse pinking than darkness and it may work even better on bottles with lower UV light filtering power (in this experiment Antique green glass bottles, with 70–80% UV reduction effect, were used). Differences among the responses of varieties are also present, with Chardonnay being less responsive to antioxidants than Sauvignon blanc. The parameters determined for the evaluation of pinking level are: Pinking potential index (PPI), proanthocyanidins (PAC), co-pigmented anthocyanins (Cp), polymeric pigmented anthocyanins (P) and total pigments (TP), as well as the absorbtion at 420 nm (for browning), 500 and 520 nm (for pinking), 620 nm (for blue shades).
© The Authors, published by EDP Sciences, 2019
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.