Macrowine 2021
IVES 9 IVES Conference Series 9 Modulating role of SO2 in white wine protein haze formation

Modulating role of SO2 in white wine protein haze formation

Abstract

Despite the extensive research performed during the last decades, the multifactorial mechanism responsible for the white wine protein haze formation is not fully characterized. Herein, a new model is proposed, which is based on the experimental identification of sulfur dioxide as a major modulating factor inducing wine protein haze upon heating. As opposed to other reducing agents, such as 2-mercaptoethanol, dithiothreitol and tris(2-carboxyethyl)phosphine hydrochloride (TCEP), the addition of SO2 to must/wine upon heating cleaves intraprotein disulfide bonds, hinders thiol-disulfide exchange during protein interactions and can lead to the formation of novel inter/intraprotein disulfide bonds. Those are eventually responsible for wine protein aggregation which follows a nucleation-growth kinetic model as shown by dynamic light scattering [1]. Protein aggregates were further studied following heat stress to induce aggregation. We were able to dissolve the aggregates in buffer A (8 M urea, 200 mM NaCl and 30 mM sodium citrate pH 3) and B (4 % SDS, 200 mM NaCl and sodium citrate pH 3). Size-exclusion chromatography (SEC) of the dissolved proteins aggregates allowed the characterization of the different species present in solution under reducing and non-reducing conditions. Determination of free sulfhydryl groups present in native and stressed protein was also performed using 5,5ʹ-dithiobis(2-nitrobenzoic acid) (DTNB). We suggest/demonstrate that protein aggregation due to SO2 modulation under wine model solution occurs as a result of the combination between both hydrophobic interactions and the formation of new interprotein disulfide bonds. DTNB assay revealed that there were no free sulfhydryl groups both in native, heat stressed and heat stressed in the presence of SO2. Future work will focus on the study of the different protein aggregate species and on new methods for wine protein stabilization.

[1] Chagas, R., Ferreira, L. M., Laia, C. A., Monteiro, S. & Ferreira, R. B. (2016). The challenging SO2-mediated chemical build-up of protein aggregates in wines. Food Chemistry, 192, 460-469.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster

Authors

Ricardo Chagas*, César Laia, Luísa Carvalho, Ricardo Ferreira, Sara Monteiro

*FCT/UNL

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Characterization of non-Saccharomyces yeast and its interaction with Saccharomyces cerevisiae with investigation of fermentation kinetics and aromatic composition

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.20.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...
Read More

Estimation of chemical age of red wines with the use of Fourier transform infrared spectroscopy (FT-IR) and chemometrics

The color of a red wine is one of the most important parameters of its quality, giving much information on its status, such as the grape variety used or the winemaking style. As the result of a complex equilibrium between different forms of anthocyanins and polymerization reactions which occur over the course of time, color can also serve as an indication of a wines’ age. For this purpose the “chemical age” i and ii indexes have been introduced by Somers in 1977. The chemical age index i measures the color absorbance after the addition of acetaldehyde while chemical index ii provides an indication of how much of the total red pigments are resistant to SO2 bleaching.

Read More

Correlations between sensory characteristics and colloidal content in dry white wines

Must clarification is an important step occurring just after grape extraction in the elaboration of white wine, consisting in a solid-liquid separation. Traditionally, low must turbidity, around 50-150 NTU, is generally reached in white winemaking in order to prevent reductive aromas and facilitating alcoholic fermentation. Alternatively, a higher turbidity (300 NTU or above) can be sought for reasons such as a better expression of grapes identity (terroir), or for getting a must matrix that could supposedly lead to wines having greater ageing potential.

Read More

Update knowledge about the presence of condensed tannins in grapes and their contributions to astringency perception

Condensed tannin is a principle group of polyphenol compounds derived from grape, greatly contributing to the bioactivity and the sensory perception of wine. Condensed tannins present as a heterogeneous mixture in nature involving various degrees of both polymerization and galloylation. Even though multiple attempts focusing on fractionation of grape condensed tannins by solid-phase have been conducted over the past decades, few individual tannins have been purified and identified. Hence, our knowledge on grape and wine condensed tannin moleculars has to be limited at the several known monomeric, dimeric and trimeric proanthocyanidins

Read More

A multivariate approach using attenuated total reflectance mid-infrared spectroscopy to measure the surface mannoproteins and β-glucans of yeast cell walls during wine fermentations

Yeast cells possess a cell wall comprising primarily glycoproteins, mannans, and glucan polymers. Several yeast phenotypes relevant for fermentation, wine processing, and wine quality are correlated with cell wall properties. To investigate the effect of wine fermentation on cell wall composition, a study was performed using mid-infrared (MIR) spectroscopy coupled with multivariate methods (i.e., PCA and OPLS-DA). A total of 40 yeast strains were evaluated, including Saccharomyces strains (laboratory and industrial) and non-Saccharomyces species. Cells were fermented in both synthetic MS300 and Chardonnay grape must to stationery phase, processed, and scanned in the MIR spectrum.

Read More