Oak barrel maturation vs. micro-oxygenation: Effect on the formation of anthocyanin-derived pigments and wine colour

The objective of this study was to check whether micro-oxygenation (MO) could mimic oak barrel ageing as regard the effect on wine colour. A red wine was submitted to micro-oxygenation for three months while another lot from the same wine was matured in oak barrels for three or six months. After these times, oak-matured and micro-oxygenated wines were bottled and analyzed six months later. The chromatic characteristics of these wines were also compared with those of a control wine that remained in a stainless steel tank all the time. Anthocyanins and anthocyanin-derived compounds were studied by LC–ESI-MS. Monomeric anthocyanins and other compounds including direct anthocyanin–flavanol adducts, ethyl-linked anthocyanin–flavanol compounds, and pyranoanthocyanins were detected. The application of MO for three months produced wines with a lower concentration of monomeric anthocyanins and a higher concentration of vitisin-related pigments than the control wine, the oak mature wines showing similar results than MO wines when aged for the same period of time. Differences were also observed in the chromatic characteristics, the micro-oxygenated and the oak matured wines showing a higher colour intensity than control wine. However, after six months in bottle differences were found between the micro-oxygenated wines and oak matured wines, the latter showing a more stable colour, probably due to the beneficial effects of compounds extracted from the wood (e.g. ellagitannins or wood aldehydes).