PECTIC ENZYME TREATMENT EFFECTS ON QUALITY OF WHITE GRAPE MUSTS AND WINES

Grapes of three white cultivars were treated with a commercial pectic enzyme preparation on an industrial scale. The effect of enzyme treatm ent on the following juice and wine volatiles was considered: fruity e sters, terpenes, alcohols, volatile phenols (4-vinylphenol and 4-vinyl guaiacol), hydroxycinnamate derivative esters (caftaric, coutaric, and fertaric esters), and free hydroxy cinnamic acids (caffeic, coumaric and ferulic acids), Pectic enzyme treatment increased the higher alcoh ols, free hydroxycinnamic acids and volatile phenols, whereas amounts of most esters, herbaceous alcohols and hydroxycinnamate derivative es ters were reduced, Terpenes, 2-phenylethanol and benzyl alcohol levels were not affected by pectic enzyme treatment. When tasted by an exper t panel, differences were found in sensory characteristics, with wines from untreated judged higher quality than those from treated grapes.