PROJECT AIMS TO IMPROVE WINES QUALITY THROUGH PH CONTROL
THE INFORMATION GENERATED WILL HELP IMPLEMENT NEW PRACTICES TO IMPROVE CURRENT WINEMAKING PROCESSES.
July 8, 2016
Generating more information to propose strategies that improve the sensory quality of wines and increase their longevity is the purpose of the researchers from the Department of Agricultural Sciences who are developing a Regular Fondecyt project in that line.
"Improving the Quality of Wine Through Ph and Minority Metals Handling: an Alternative to Delaying the Oxidation and Reducing the Use of Sulphites" is the name of the project led by Professor Felipe Laurie and whose research team includes the academic from the University of Chile, María Carolina Zúñiga and Yanaris Mirabal and Veronica Carrasco, post-doctoral researchers from our University.
Felipe Laurie and Yianaris Mirabal participated recently in the Macrowine World Congress, held in Nyon, Switzerland, in which more than 200 research works on different wine-related lines were presented.
As explained by the director responsible for the project, it is sought to improve the available information on aspects of winemaking where pH and metal catalysts are fundamental, although they have not been widely studied.
"Therefore, the information produced as a result of this project will contribute to the knowledge to unravel some of the effects of metal ions on the pH and on the quality of the wine and its longevity, and will help to propose new practices to improve the ones that are currently used in winemaking," said the researcher.
He also explained that the metallic metabolizers compounds are minerals like iron and copper that are naturally present in wines, they come from the land and, despite coming in very low concentrations, they affect chemical processes and can generate oxidation more quickly.
In addition, oxygen is one of the fundamental variables contributing to oxidative processes, and from the greater or lesser exposure to this, it can achieve greater or lower sensory transformations in the wine.
Likewise, the content of metals such as iron and copper are relevant because they function as catalysts of these chemical reactions.
There are antioxidant agents that limit the progress of the oxidative processes. One in particular is sulphur dioxide, which is able to restrict the effects of these processes.
On the other hand, the researcher explained that the pH of grapes and wines is possibly the most important parameter influencing the quality of the final product. "In all stages of growing grapes for wine making, the pH is essential in the regulation of aspects such as availability of nutrients from the soil, the activity and proliferation of microbes, speed and balance of important chemical reactions, the sensory properties of grapes and wines, etc.", he said.
He also said that recent information on the development of oxidation and taste in wines has shown the key role of trace metals in the progress of these reactions. "If the handling of the wine’s pH and trace metals improves, wines would be less prone to oxidation, it would require a lower amount of sulfites and would have more stability and longer life, with a best aromatic potential", he noted.
About the wines more potentially prone to undergo oxidation, the scientist from Department of Agricultural Sciences said that this depends on each product, given that some improve with aging and subsequently decay, while others “are wonderful when freshly produced and shortly thereafter they begin to decline, modifying their color and losing aroma ". He added that, in general, white wines have a shorter life, as they oxidize more quickly.
On the characteristics of an oxidized wine, Felipe Laurie said that there is a change in the color of white wines. The same occurs in red wines, getting brown or orange shades and oxidation aromas appear, similar to non-refrigerated butter.
For the development of their project, the research team will perform a series of tests in the lab and in production at the cellar scale, with the purpose of studying the effects of the acidity and the metal catalyst during wine oxidation. They will also assess the effects of cationic-exchange resins treatments – a technology available on the market - on the oxidative stability of the treated wines. "In the same way, this research project leads to suggest strategies to reduce the use of sulfites and improve the quality of the wine and its longevity," he said.
Projects like this are particularly important to the wine industry, which has positioned itself as one of the most dynamic sectors today, with increasing presence in export markets.