Colour stabilisation properties of oenological tannins during wine ageing

The use of oenological tannins is authorized for many years by the OIV and advised for color stabilization. For this reason, winemakers look for a better understanding of tannins/anthocyanins interactions to produce deeply colored wines with great color stability during aging. Consequently, the aim of this work, was to verify/confirm the effectiveness of oenological tannins on wine color stabilization to be applied as a new tool by winemakers. 

To achieve this, a model wine solution was supplemented with 10, 20 and 40 g/hL of commercial tannins (quebracho, ellagitannin, gallotannin, grape-skin and grape-seed) or (-)-epicatechin used as reference. After 1, 7, 14 and 21 days, the full absorbance spectrum (400-800 nm) was measured to determine the CIELAB coordinates and the copigmentation index (new proposed index based on CIELAB parameters). In parallel, samples were injected in HPLC-MS-QTOF to quantify the malvidin-3-O-monoglucoside and its possible degradation products.

Did malvidin-3-O-glucoside concentration decrease and did we witness the formation of degradation products? Do these results differ based on the added tannins? Which tannins proved to be the most efficient to improve color stabilization during ageing by copigmentation and by inducing the formation of new polymerized pigments respectively?

DOI: https://doi.org/10.53144/infowine.en.2022.04.002

Video of the seminar held during Enoforum Italia 2021 (18-20 May 2021)

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