Estabilização tartárica de vinhos tintos por combinação de nanofiltração e permuta catiónica

Abstract

Tartrate precipitation of wine is a natural and unpredictable phenomenon. So in the production of red white and rosé wines is always included a tartaric stabilization step before bottling. The permission for using cation exchangers, since 2009, Reg (EC) Nº 606/2009, has opened a new field of action in the processes of tartaric stabilization. The implementation of a non expensive and versatile system for tartaric stabilization, using equipment which can also be used for other applications, with a minimum impact on wine sensory properties is certainly appealing. This work aims to study the application of nanofiltration in association with cation exchange of the potassium rich permeate for the tartaric stabilization of red wine. The comparison of the behavior of four cationic resins, Dowex Monosphere 88, Pentacque Stab, AEB and Amberjet 1200H, in exchange of a model solution rich in potassium, did not show any noticeable differences. None of the resins reached the saturation point in the 6 hours time course of the assays. The tartaric stabilization results obtained from the combination of nanofiltration with cation exchangers, showed that this process is effective. The decrease in the conductivity of wine was monitored until the intended value was reached. There was a reduction in the potassium content considerably greater than that of calcium, due to the relative impermeability of the nanofiltration membrane, Trisep XN45 TSF 4040, to calcium. The total acidity increased and the pH decreased, resulting in a sharp acidification of the wine and an impact on the tonality (more red) and on the Color Intensity (higher). The value of the Index of Total Polyphenols, tannins and anthocyanins didn’t change, meaning that these molecules did not pass through the membrane used in the nanofiltration. The tasting assays performed showed that the treated wines were significantly different from the control wine and from a wine directly exchanged on the resins. Despite the increase in acidity, the treated wines were preferred by the panel, due to a cleaner and more clear flavour . The control wine did not show a significant difference when compared to the wine directly exchanged on the resins. The stabilization process described above, although being more expensive and requiring a bigger investment than the direct cation exchange, requires less investment than the electrodialysis and the cold stabilization. On the other hand, it is a very versatile device which can enable operations such as the dealcoholization and off-flavors removal, among others.

Date of Award	2012
Original language	Portuguese
Awarding Institution	Universidade Católica Portuguesa
Supervisor	José António Couto (Supervisor) & Maria da Conceição Hoog (Supervisor)