The Production of Reduced-Alcohol Wine Using Glucose Oxidase Treated Juice. Part I. Composition

¹ Viticulture and Oenology Group, Faculty of Science and Technology, Eastern Institute of Technology, Private Bag 1201, Taradale, New Zealand
² Wine Science Group, Lincoln University, Canterbury, New Zealand.

gpickering{at}eit.ac.nz

The effects of treatment with glucose oxidase (GOX) on grape juice and the composition of the resultant reduced-alcohol wine were investigated. Grape juice glucose was converted to gluconic acid by GOX, and conversion efficiencies of 87% and 74% were obtained for Müller-Thurgau and Riesling juices, respectively. The alcoholic fermentation of these GOX-treated juices proceeded without incident, and final ethanol concentrations of 6.3% to 6.5% v/v were obtained, corresponding to a 36% to 40% reduction in alcohol compared to control wines. Large amounts of gluconic acid are formed during treatment with glucose oxidase and are present in the finished wine, although a reduction in content occurs from precipitation reactions during the alcoholic fermentation. At bottling the pH of GOX wines are very similar to those of control wines, although titratable acidity remains significantly higher. Higher A₄₂₀ values were observed with GOX wines compared to control and aeration wines. Increased quinone production and regeneration of oxidizable phenolic substrate are suggested as possible hypotheses accounting for these observations.

Key words: reduced-alcohol wine, low-alcohol wine, glucose oxidase, catalase, reduced sugar grape juice, juice oxidation, composition

Submitted on January 28, 1998
Revised on April 29, 1999