Abstract

YANG, Yi; DEED, Rebecca C.; ARAUJO, Leandro D.  and  KILMARTIN, Paul A.. The Influence of Micro-oxygenation on the Long-term Ageing Ability of Pinot noir Wine. S. Afr. J. Enol. Vitic. [online]. 2022, vol.43, n.1, pp.39-45. ISSN 2224-7904.  http://dx.doi.org/10.21548/43-1-4841.

In this study, Pinot noir wines were bottle aged for 12 and 18 months after micro-oxygenation (MOX) applied before or after malolactic fermentation (MLF) at two doses (10.8 and 52.4 mg/L/month). After ageing, a greater decrease in the total SO₂ concentration was found in wines with the higher MOX dosage, demonstrating a long-term impact of higher oxygen exposure on wines' SO₂ requirement. Meanwhile, a negative impact of MOX on wine colour development occurred over time, resulting in a large loss of colour measures (i.e., 420 nm for brown hues, 520 nm for red colour, SO₂ resistant pigments, and colour intensity), which was greater with the early oxygen exposure. This was linked to a significantly lower content of large polymeric pigments in MOX treatments. Tannin concentration was, in the end, not affected by the MOX treatments. However, regarding tannin composition, considerably higher (-)-epicatechin extension units but much lower (-)-epicatechin terminal units were found with MOX treatments. In addition, a significant reduction of tannin trihydroxylation (%Tri-OH) but a higher galloylation (%Galloyl) and mean degree of tannin polymerisation (mDP) remained in wines with MOX, indicating a long-term negative influence on astringency intensity.

Keywords : Micro-oxygenation; Pinot noir; ageing ability; colour development; phenolic composition.

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