Effect of nanofiltration on the chemical composition and wine quality
Abstract
In Enology the conventional processes of filtration for clarification and stabilization are giving place to alternative membrane processes, including nanofiltration (NF). Furthermore, the increased alcohol content in wines recorded in recent years became an important issue for all the main wine producing countries. Among techniques available to the wine industry to reduce the ethanol content, NF is certainly one of the newest. This study is focused on the evaluation of NF influence on wine physical-chemical composition, including mineral content, which in accordance to our best knowledge is a novelty. NF essays at laboratorial scale using a cellulose acetate membrane prepared and characterized for this purpose were carried out, at a first stage with model solutions (to better understanding of wine NF results) and later with white and red wines from three Portuguese Denominations of Origin (DO), Dão, Palmela and Óbidos. Regarding model solutions trials, high rejection to tartaric acid and low rejection to ethanol were observed. Wines and respective NF fractions were evaluated in terms of physical-chemical composition, comprising summary analysis parameters, organic acids, total anthocyanins, total phenols index, total polysaccharides and multi-elemental composition. As expected, ethanol was preferentially permeated by the membrane. Rejections to tartaric, lactic, malic and acetic acids, phenolic compounds and mineral elements were in general very high. Concerning polysaccharides a complete retention was verified. For the majority of chemical compounds concentrations in final feed increased with NF treatment, due to water and ethanol removal. Considering NF use for wine dealcoholisation, alcoholic strength in final feed can be reduced by reposition of the permeated water, after separation by distillation.
Issue: Macrowine 2016
Type: Poster
Authors
*ISA