Articles
Enzymatic reduction of glucose from grape must using glucose oxidase as a strategy for the production of low-alcohol wine
Article number
1418_49
Pages
391 – 400
Language
English
Abstract
Increasing temperatures as a result of climate change, the application of modern viticultural technologies, as well as the use of highly alcohol-tolerant selected yeast strains, have gradually led to the production of wines with higher alcohol concentrations.
On the contrary, consumers’ preference for wines with lower ethanol content, which are generally perceived as healthier, has become increasingly evident in recent years.
One of the most promising processes for obtaining wines with a lower alcohol concentration than the potential of the grapes at harvest is the enzymatic reduction of glucose from grape must using glucose oxidase (GOX). The current studies aimed to evaluate the action of GOX, both in free form (produced by Aspergillus niger) and immobilized (Gluzyme Mono 10000 BG), in citrate buffer solutions (0.1 M), synthetic media (MMM) and grape must, with or without the addition of catalase (CAT). Tested in synthetic media, GOX catalyzed the transformation of over 50% of the glucose, the enzymatic reaction being strongly influenced by the pH of the solutions.
The application of GOX in grape must (Muscat Ottonel; pH 4.00) for 24 h at 25°C, with intermittent aeration, led to a reduction in glucose content by up to 12.90% (24 g L‑1), in parallel with gluconic acid accumulation (<4.00 g L‑1), being obtained wines with a lower alcohol concentration of up to 1.05% (v v‑1), but with higher values of volatile acidity and the browning index (DO420 nm) and lower non-reducing extract, which may adversely affect their sensory perception.
On the contrary, consumers’ preference for wines with lower ethanol content, which are generally perceived as healthier, has become increasingly evident in recent years.
One of the most promising processes for obtaining wines with a lower alcohol concentration than the potential of the grapes at harvest is the enzymatic reduction of glucose from grape must using glucose oxidase (GOX). The current studies aimed to evaluate the action of GOX, both in free form (produced by Aspergillus niger) and immobilized (Gluzyme Mono 10000 BG), in citrate buffer solutions (0.1 M), synthetic media (MMM) and grape must, with or without the addition of catalase (CAT). Tested in synthetic media, GOX catalyzed the transformation of over 50% of the glucose, the enzymatic reaction being strongly influenced by the pH of the solutions.
The application of GOX in grape must (Muscat Ottonel; pH 4.00) for 24 h at 25°C, with intermittent aeration, led to a reduction in glucose content by up to 12.90% (24 g L‑1), in parallel with gluconic acid accumulation (<4.00 g L‑1), being obtained wines with a lower alcohol concentration of up to 1.05% (v v‑1), but with higher values of volatile acidity and the browning index (DO420 nm) and lower non-reducing extract, which may adversely affect their sensory perception.
Publication
Authors
V.R. Filimon, R.M. Filimon, R. Pașa, A. Nechita, D. Damian
Keywords
catalase, enzymatic reaction, ethanol, grape juice, oxidation, pH
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