Colour-related phenolics, volatile composition, and sensory profile of Nero di Troia wines treated with oak chips or by micro-oxygenation

The changes of Nero di Troia wines submitted to micro-oxygenation or treatment with oak chips were studied. Oak chips favoured polymerization reactions (SPP, LPP, I (HCl), polymeric phenols, and polymeric pigments, respectively +28, +67, +44, +60, and +73 % in comparison with the untreated wines, 12 months after racking). The polymerization reactions increased colour stability (colour intensity, and % of red and blue colour of the oak-treated wines were +11, +2, and +10 % compared to the control). At the end of ageing, the oak-treated wines had the highest concentrations of alcohols, carbonyl compounds, and lactones, while the highest contents of acids and esters were detected in the micro-oxygenated wines. The sensory profile of the oak-treated wines was characterized by the attenuation of floral, fruity, and vinous attributes. Concerning the phenolic profile, micro-oxygenated wines showed the highest concentrations of anthocyanins (+23 % respect to the untreated samples and +306 % respect to the oak-treated ones) and of flavan-3-ols (+24 % respect to the untreated samples and +95 % respect to the oak-treated ones). Micro-oxygenation reduced astringency and herbaceous character and intensified spicy and fruity flavours.