The Effects of Low-Level Oxidation in Winemaking on Phenolic Constituents and Herbal Character

In the last few years, the use of commercial devices to introduce small amounts of oxygen into wines in production stages has become very popular. Beneficial effects such as ?softer tannins?, color stabilization, and reduction of herbal character have been claimed without scientific support. The purpose of this project is evaluating the effects of micro-oxygenation in analytical and organoleptic attributes of wine. Six month ago, commercial treated and untreated wines were analyzed, a large commercial scale trial was conducted, and a novel experiment under highly controlled conditions is about to start. At the time, we have found that the oxygen treatments can produce variations in composition of specific species and classes of phenolic compounds; for instance, significant lost of quercetin have been observed. At the end of this project, we expect to confirm these preliminary results, recognize the reasons for the variation between wines, and hopefully identify some aspects of the chemical mechanisms involved in these reactions.