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Original scientific paper

https://doi.org/10.31727/gzb.43.6.11

Influence of laccase and polyvinylpyrrolidone on the quality and phenolic composition of Laški Riesling wine

Zrinka Čosić ; Prehrambeno-biotehnološki fakultet, Sveučilište u Zagrebu, Hrvatska
Branka Levaj ; Prehrambeno-biotehnološki fakultet, Sveučilište u Zagrebu, Hrvatska
Mara Banović ; Prehrambeno-biotehnološki fakultet, Sveučilište u Zagrebu, Hrvatska


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Abstract

Phenolic compounds, with their well known positive effect on human health, are a desirable constituent of wine, however, due to their susceptibility to oxidation, they can negatively affect the color, stability and overall quality of white wines. Sulphur dioxide, the effective antioxidant used for wine browning prevention and stabilization, is avoided cause of possible harmful effect on human health and wine quality. Therefore, other agents such as polyvinylpolypyrrolidone (PVPP) and laccase are used, and investigated as well still , too. PVPP ( a synthetic polymer) binds phenolic compounds and thus prevents their oxidation. In contrast, the enzyme lacase catalyzes the oxidation of phenolic compounds and accelerates the formation of high molecular weight brown polymers which are removed in finalization processes such as ultrafiltration. In this way, the subsequent oxidation of phenolic compounds as well as wine browning and turbidity are prevented. Considering the above facts, the aim of this study was to examine the effectiveness of treatment with PVPP or laccase, combined with ultrafiltration, on the physicochemical properties (contents of ethanol, total extract, volatile and non-volatile acids, pH value, color intensity), sensory quality and the concentration of individual groups of phenolic compounds (flavonoids, neflavonoids, condensed tannins, leukoanthocyanidins) of Laški Riesling white wine. Finalization of untreated (control) wine and wines treated with PVPP or laccase and treated wines was performed by ultrafiltration. The selected experimental conditions were previously tested in laboratory scale and confirmed that colloid content was reduced by treatments with PVPP or laccase. while wine aroma was not significantly impaired. Further, the same treatments were applied in the industrial conditions and according to obtained results they did not significantly affect the basic physicochemical properties, but improved the sensory quality of the treated wines. Therefore, the same treatment conditions were applied in industrial scale and generally did not significantly affect the physico-chemical properties, while the sensory quality of the treated wines were improved. The concentrations of all groups of phenolic compounds and color intensities were reduced in the treated wines when compared to color control wine. The obtained results indicate the suitability of both PVPP and laccase in the processes of stabilization and color preservation of white wine Laški Riesling.

Keywords

white wine, browning, phenolic compounds, laccase, PVPP

Hrčak ID:

247765

URI

https://hrcak.srce.hr/247765

Publication date:

11.12.2020.

Article data in other languages: croatian

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