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 treatment on the following juice and wine volatiles was considered: fruity esters, terpenes, alcohols, volatile phenols (4-vinylphenol and 4-vinylguaiacol), hydroxycinnamate derivative esters (caftaric, coutaric, and fertaric esters), and free hydroxy cinnamic acids (caffeic, coumaric and ferulic acids). Pectic enzyme treatment increased the higher alcohols, free hydroxycinnamic acids and volatile phenols, whereas amounts of most esters, herbaceous alcohols and hydroxycinnamate derivative esters were reduced. Terpenes, 2-phenylethanol and benzyl alcohol levels were not affected by pectic enzyme treatment. When tasted by an expert panel, differences were found in sensory characteristics, with wines from untreated judged higher quality than those from treated grapes.