 IVES 9 IVES Conference Series 9 Tuning the pH during the fermentation has a strong effect on the wine protein composition and the stability of the resulting white wines

Tuning the pH during the fermentation has a strong effect on the wine protein composition and the stability of the resulting white wines

Abstract

AIM: Previous results have shown the impact of the pH on the stability of white wine proteins. In a context of global warming that implies increases in ethanol content and pH, we wanted to compare for the same initial must (given composition in polysaccharides, polyphenols, ions, _) the impact of the pH on the protein composition after fermentation. Several white wine varieties were considered.

METHODS: Vinifications were carried out using musts from Sauvignon, Muscat, Sylvaner, Riesling, Gewurztrminer, and Pinot Gris). The pH of the initial musts was adjusted to 3.0, 3.3, 3.6 and 3.9. For each wine thus obtained, heat tests (heating at 40°C for 4 hours) were carried out and proteins were analyzed and quantified by gel electrophoresis.

RESULTS: On the whole, protein concentrations in wines decreased during fermentation. However, this decrease was more marked for the lowest pH (3.0 and 3.3), as well as for some proteins (chitinases, b-glucanases). Thus the total concentration of proteins was higher at pH 3.9. The turbidity measured after heat tests evolved differently: a maximum was observed at pH 3.6 in the present experimental conditions (40°C- 4h).

CONCLUSIONS

This study confirms that the pH has a decisive impact on the protein composition in white wines, with higher pH favoring their conformational stability during winemaking. However, haze formation due to heat-induced denaturation of proteins is higher at high pH. This trend was observed whatever the studied variety, but with more or less haze intensities. This indicated also an impact of non-protein compounds, whose composition strongly depends on the grape variety.

DOI:

Publication date: September 14, 2021

Issue: Macrowine 2021

Type: Article

Authors

Céline Poncet-Legrand

INRAE,Eric MEISTERMANN, IFV Aude VERNHET, Institut Agro, Montpellier SupAgro Philippe COTTEREAU, IFV Frédéric CHARRIER, IFV Patrick CHEMARDIN, INRAE Céline PONCET-LEGRAND, INRAE

Contact the author

Keywords

white wines, haze formation, proteins, pH

Citation

First large-scale study of thiol precursor distribution in red grape berry compartments and implications for thiol-type red wine production

Climate change and the growing need to reduce the use of phytosanitary products demand the exploration of disease-resistant grape varieties and/or adapted to drought conditions.

Evaluation of winegrape anthocyanins in the vineyard using a portable fluorimetric sensor: seasonal and water regime effects

Accumulation of anthocyanins (Anth) on whole winegrape (Vitis vinifera L.) bunches attached to the vine was monitored by a fluorescence-based sensor (Multiplex) on ‘Aleatico’ and ‘Nero d’Avola’. Different water regimes were applied.

Methodological approach to zoning

An appellation or geographic indication should be based on the terroir concept in order to ensure its integrity. The delimitation of viticultural terroirs must include two consecutive or parallel steps, namely (a) the characterisation of the environment and identification of homogenous environmental units (basic terroir units, natural terroir units) taking all natural factors into account, as well as (b) the characterisation of the viticultural and oenological potential of these units over time.

Genetic prospecting of rainfed viticulture in the region with the largest cultivated area in Chile

The Maule region hosts up to a third of the total area of vineyards in Chile, in an environment where ancient practices inherited from the colonial past coexist with modernity and dynamism that include technified irrigation and fine vines. In the dry land of Maule there is a viticulture that has subsisted with ancient vines and traditions transmitted over generations, and there is little clarity about the origin and classification of the Maule viticulture, giving rise to the use of different concepts as synonyms to describe the ancient, minority, patrimonial or Criollas vines. In order to characterize and protect the ancient material, we studied the genetic diversity of a territorial collection that covers 80% of the communes of the region, prioritizing plants established more than 40-60 years ago.

Phytosterols and ergosterol role during wine alcoholic fermentation for 27 Saccharomyces cerevisiae strains

Sterols are a class of the eukaryotic lipidome that is essential for the maintenance of the cell membrane integrity and their good functionality (Daum et al., 1998).