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…

Evaluation of Polarized Projective Mapping as a possible tool for attributing South African Chenin blanc dry wine styles

Multiple Factor Analysis (MFA) According to the Chenin blanc Association of South Africa, there are three recognized dry wine styles, Fresh and Fruity (FF), Rich and Ripe Unwooded (RRU), and Rich and Ripe Wooded (RRW), classically attributed with the help of sensory evaluation. One of the “rapid methods” has drawn our attention for the purpose of simplifying and making style attribution for large sample sets, evaluated during different sessions, more robust. Polarized Projective Mapping (PPM) is a hybrid of Projective Mapping (PM) and Polarised Sensory Positioning (PSP). It is a reference-based method in which poles
(references) are used for the evaluation of similarities and dissimilarities between samples.

Fingerprinting the origin of rosé wines with a new high throughput polyphenomics method

Wine is a widely consumed alcoholic beverage with a high commercial value. More specifically, the worldwide consumption of rosé wine has increased by 20% since 2002[1]. But because of its high commercial value, it can become a subject of fraud, and authenticity control is necessarily required. More than one hundred polyphenols have been recently quantified in various rosé wines [2]. They are key components defining color, taste and quality of wines. Their amount and composition depend on many different factors such as grape variety, winemaking and age of the wine. In this study, the influence of geographic origin of some rosé French wines was investigated. An original and very fast UPLC-QTOF-MS method was developed and used to predict the geographic origin authenticity of rosé wines.

How small amounts of oxygen introduced during bottling and storage can influence the metabolic fingerprint and SO2 content of white wines

The impact of minute amounts of headspace oxygen on the post-bottling development of wine is generally considered to be very important, since oxygen, packaging and storage conditions can either damage or improve wine quality. This is reflected in the generalised use of inert bottling lines, where the headspace between the white wine and the stopper is filled with an inert gas. This experiment aimed to address some open questions about the chemistry of the interaction between wine and oxygen, crucial for decisions regarding optimal closure. While it is known that similar amounts of oxygen affect different wines to a variable extent, our knowledge of chemistry is not sufficient to construct a predictive method.

Micro-meteorological, compositional and transcriptional study of corvina grape color during ripening

Grape anthocyanin content and composition could affect the quality and the production strategies of red wines. Differences in the pigment composition modify the color properties in terms of hue, extractability and stability. Thus, for the production of a highly qualitative wine such as “Amarone”, variations in the pigment composition are not negligible. The aim of this work was the investigation of the anthocyanin profile changes during ripening in Corvina grapes, the main cultivar for the “Amarone” production. The experiment took place in 2015, in two vineyards located in Valpollicella (Italy).

Determination of metallic elements in Chilean wines by atomic absorption spectroscopy and inductively coupled plasma–mass spectrometry

The chemical composition of wines depends on series of variables such as the type of grape, edaphoclimatic conditions, and viticulture and winemaking practices employed during production. Metallic elements play a significant role during winemaking (e.g. as catalysts of oxidation reactions) and have been previously employed for the classification of wines according to provenance. In this work, we focused on the analysis of metallic elements (K, Na, Ca, Zn, Cu, Fe, Mg, Mn, Ni, Cr, Al, Pb, Cd, Hg, Se, Co, Sn and As) in 145 Chilean wine samples (102 reds and 43 white wines), of seven grape varieties, and five of the major wine producing regions in Chile.