Stability of White Wine Proteins: Combined Effect of pH, Ionic Strength, and Temperature on Their Aggregation

Protein haze development in white wines is an unacceptable visual defect attributed to slow protein unfolding and aggregation. It is favored by wine exposure to excessive temperatures but can also develop in properly stored wines. In this study, the combined impact of pH (2.5–4.0), ionic strength (0...

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Bibliographic Details
Published in:Journal of agricultural and food chemistry 2012-02, Vol.60 (5), p.1308-1319
Main Authors: Dufrechou, Marie, Poncet-Legrand, Céline, Sauvage, François-Xavier, Vernhet, Aude
Format: Article
Language:English
Subjects:
beta-glucanase
Biological and medical sciences
electrostatic interactions
Fermented food industries
Food industries
Fundamental and applied biological sciences. Psychology
Hydrogen-Ion Concentration
ionic strength
isoelectric point
Life Sciences
Osmolar Concentration
Plant Proteins - chemistry
protein isoforms
Protein Stability
proteins
Temperature
Vegetal Biology
white wines
Wine - analysis
Wines and vinegars
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Summary:Protein haze development in white wines is an unacceptable visual defect attributed to slow protein unfolding and aggregation. It is favored by wine exposure to excessive temperatures but can also develop in properly stored wines. In this study, the combined impact of pH (2.5–4.0), ionic strength (0.02–0.15 M), and temperature (25, 40, and 70 °C) on wine protein stability was investigated. The results showed three classes of proteins with low conformational stability involved in aggregation at room temperature: β-glucanases, chitinases, and some thaumatin-like protein isoforms (22–24 kDa). Unexpectedly, at 25 °C, maximum instability was observed at the lower pH, far from the protein isoelectric point. Increasing temperatures led to a shift of the maximum haze at higher pH. These different behaviors could be explained by the opposite impact of pH on intramolecular (conformational stability) and intermolecular (colloidal stability) electrostatic interactions. The present results highlight that wine pH and ionic strength play a determinant part in aggregation mechanisms, aggregate characteristics, and final haze.
ISSN:0021-8561
1520-5118
DOI:10.1021/jf204048j