Comparison of the principal production methods for alcohol-free wine based on analytical parameters

Abstract

Production, demand, and brand awareness of dealcoholized wine (<0.5% v/v) is steadily increasing worldwide. However, there have been few studies to date investigating and comparing the different physical processes for dealcoholizing wine. This study examines the differences in the analytical parameters of the main membrane and thermal methods currently employed to remove ethanol from wine and produce dealcoholized wine [1-7]. A total of 600 litres of Spanish white wine from the 2023 vintage served as the base. The wine was dealcoholized using leading thermal methods—vacuum distillation, Spinning Cone Column, and traditional distillation. Additionally, it underwent dealcoholization using key membrane techniques, such as osmotic distillation and dialysis, in combination with other methods: reverse osmosis followed by osmotic distillation of the permeate, reverse osmosis paired with dialysis, and reverse osmosis alone to produce an alcohol-free base by adding demineralized water to the retentate before applying dialysis. Each approach was replicated three times to ensure consistency in results. The batches were stabilized post-process with sulphur dioxide and Nagardo®, a natural preservative, before bottling. After one month of storage in bottles, each sample was analysed: colour parameters were measured with a spectrophotometer [8], key minerals were determined using, basic wine parameters assessed via FTIR [9], redox (mV) with ORP sensor, further parameters like total phenols was determinate by Folin-Ciocalteu reagent and spectrophotometer, and acetaldehyde are determined through UV-enzymatic method.

The findings demonstrated distinct variations in key analytical parameters across the different dealcoholization techniques. Membrane-based methods, particularly reverse osmosis combined with osmotic distillation, exhibited superior retention of essential compounds and colour stability compared to thermal processes. In contrast, thermal techniques, such as vacuum distillation and traditional distillation, resulted in significant colour degradation. Advanced analyses using atomic absorption spectrometry, FTIR, and NMR highlighted changes in mineral content and structural components of the wine matrix, underscoring the critical impact of the chosen dealcoholization process on wine quality. Further, the results obtained are extensively discussed in the presentation.

References

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