Potential Contribution of Climate Change to the Protein Haze of White Wines from the French Southwest Region

Abstract

The aim of this study was to evaluate the role played by climatic conditions during grape ripening in the protein instability of white wines produced in the French southwest region. For this purpose, basic wine analyses were carried out on 268 musts and the corresponding wines, all produced during the 2016, 2017, 2018, and 2019 vintages, with distinctive climatic conditions. Qualitative and quantitative variables were correlated with levels of protein haze determined by heat test (80 °C/2 h) in the wines using analysis of covariance (ANCOVA), principal component analysis (PCA), and classification and regression trees (CART). Our results show that the climatic change, with the increase in temperatures, and the decrease in precipitation during the grape ripening phase, tends to enhance the risk of protein instability in wines. Indeed, the values of pH, titratable acidity, and malic acid concentrations of the musts, which are good indicators of the conditions in which the grapes ripened and of the level of ripeness of the grapes, were also the variables that correlated best with the protein haze. By measuring these parameters at harvest before alcoholic fermentation, it may be possible to predict the risk of protein haze, and thus early and precisely adapt the stabilization treatment to be applied.

The macromolecular diversity of Italian monovarietal red wines

“…Additionally, the extractability of these compounds increases during ripening due to the softening of the cell walls (Gil et al, 2012;Vicens et al, 2009). Other factors that could contribute to explaining the intra-varietal differences described here could be ascribed to differences in viticultural practices (e.g., irrigation, fertilisation) leading to modifications in the micro-environmental conditions between vineyards of a given area, leading to variations in the metabolism within each variety (Pasquier et al, 2021). Obviously, differences in the maceration step (e.g., length, temperature, and modality, frequency and intensity of the cap management) also directly affect the extraction of proteins (Gómez-Plaza et al, 2002) and polysaccharides (Gil et al, 2015;Martínez-Lapuente et al, 2021) from the skins, leading to different quantities of these macromolecules in wines.…”

Haze Formation and the Challenges for Peptidases in Wine Protein Fining

“…Wine haze is not promoted by any particular singular factor but rather by a combination of haze inducing elements and physicochemical conditions, which result in protein aggregation. ,, These factors include the (in)­stability of different HUP isoforms, pH, ionic strength, temperature and concentration of phenolic compounds, sulfite ions, and polysaccharides. , …”

“…Several factors such as grape cultivar, climate, , soil conditions, pathogen attack, winemaking ,, and clarification processes ,, can affect the wine protein composition. The pathogen-related (PR) proteins TLPs and CHIs are expressed in response to pathogenic attacks during all stages of grape development .…”

“…Wine haze is not promoted by any particular singular factor but rather by a combination of haze inducing elements and physicochemical conditions, which result in protein aggregation. 2,4,10 These factors include the (in)stability of different HUP isoforms, pH, ionic strength, temperature and concentration of phenolic compounds, sulfite ions, and polysaccharides. 11,12 Although some controversies exist, there is a consensus in the literature that wine haze results from the subsequent steps of: (1) slow denaturation of HUPs; 13 (2) exposure of hidden hydrophobic domains and binding sites; (3) binding of chemical compounds (nonproteinaceous factors known as "factor x"); (4) improper refolding; and (5) finally protein cross-linking to form particulate aggregates.…”

Mass Spectrometry-Based Proteomic Profiling of a Silvaner White Wine

“…The on-going climate change has also been shown to affect the quality of Franconian Silvaner wines, particularly increasing sugar levels and decreasing acidity, thereby altering the wines’ sensory characteristics [ 4 ]. Furthermore, increased temperatures and decreased precipitation amounts, a frequent consequence of climate change in many wine growing regions, increased the risk for protein haze formation in the wine [ 5 ]. Proteins that survive the vinification process can interact with other wine components (e.g., ethanol) to influence the wine aroma, flavor, texture astringency, and color [ 6 ].…”