4-Ethylphenol and 4-ethylguaiacol depletion in wine using esterified cellulose

The ability of cellulose acetate, cellulose acetate propionate (CAP), cellulose acetate butyrate and cellulose propionate (CP) fibres to reduce 4-ethylphenol and 4-ethylguaiacol, causing the off-flavour named “Brett character”, was studied. CAP and CP performed best in a preliminary comparative test. The former was chosen because of its more favourable FDA classification for food contact substances. CAP effectiveness was studied in relation to the reduction in volatile phenols with doses of up to 20 g/l and wine contact times of up to 60 min. Using 4 g/l, reduction of both phenols was, on average, 31–32% in defective red wines. Wine treatment affected neither colour nor total proanthocyanidins and catechins, and wines were judged to be better than the corresponding spoiled controls. CAP fibre can be regenerated by washing with ethanol or aqueous solution (pH 12), without notable changes in depletion efficiency. The technological characteristics of CAP and, to a lesser extent, CP offer interesting prospects for producing filtration beds, pads and membranes for the treatment of wines and beverages affected by “Brett character”.