IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 Composition and molar mass distribution of different must and wine colloids

Composition and molar mass distribution of different must and wine colloids

Abstract

A major problem for winemakers is the formation of proteinaceous haze after bottling. Although the exact mechanisms remain unclear, this haze is formed by unfolding and agglomeration of grape proteins, being additionally influenced by numerous further factors. For instance, increased levels of polyphenols and sulfate ions, high pH and ionic strength, and increased storage temperatures have been discussed to promote haze formation. In contrast, organic acids and polysaccharides appear to inhibit protein agglomeration (Albuquerque et al. 2021). To avoid haze formation, winemakers use bentonite to reduce protein levels in the wine before bottling. However, the bentonite treatment imposes negative side effects such as losses in wine quantity and quality, as well as costs of bentonite waste disposal (van Sluyter et al. 2015). To better understand haze formation and to find alternative procedures for protein removal e.g. by enzymatic treatments, detailed insights into the composition of the wine colloids might be helpful.
Prior to characterization, colloids were isolated from five different musts (four varieties from five vineyards, three with pectinase treatment) and their corresponding wines by ultrafiltration (10 kDa cut-off) and freeze-drying. Protein and carbohydrate composition were determined after hydrolysis by ion chromatography and high-performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), respectively. Molar mass distribution of colloids was determined by size exclusion chromatography with multi angle light scattering in combination with an UV and RI detector (SEC-UV-MALS-RI).
Colloids were found to contain a wide range of 8.9 to 67.1 g protein and 28.1 to 78.0 g carbohydrates per 100 g dry matter. Thus, protein concentrations in must and wine were been between 0.06 and 0.40 g/L and carbohydrate concentrations between 0.17 and 0.65 g/L. While there were just minor differences in the amino acid composition between the musts and wines, the carbohydrate composition was different in the samples. For instance, arabinose and galactose were the main sugars found in all hydrolyzed must colloids, while galacturonic acid was present in higher amounts in those not treated with pectinase. After fermentation, mannose was found to be the main sugar in hydrolyzed wine colloids. SEC-UV-MALS-RI showed that the colloids contained three main fractions. Two carbohydrate-rich fractions with average molar masses from 931 to 22,617 kDa and from 80 to 495 kDa as well as a proteinaceous fraction with an average molar mass between 16 to 44 kDa.
Our results indicate that colloid concentration and composition in wine is heavily influenced by variety, vineyard and oenological practices. The isolated colloids and the analytical methods will in the future be used to screen for enzyme preparations suitable to degrade proteins in must and wine to avoid haze formation.

References

Albuquerque, Wendell; Seidel, Leif; Zorn, Holger; Will, Frank; Gand, Martin (2021): Haze Formation and the Challenges for Peptidases in Wine Protein Fining. In: Journal of Agricultural and Food Chemistry 69, S. 14402–14414.
van Sluyter, Steven C.; McRae, Jacqui M.; Falconer, Robert J.; Smith, Paul A.; Bacic, Antony; Waters, Elizabeth J.; Marangon, Matteo (2015): Wine Protein Haze: Mechanisms of Formation and Advances in Prevention. In: Journal of Agricultural and Food Chemistry 63 (16), S. 4020–4030.

DOI:

Publication date: June 23, 2022

Issue: IVAS 2022

Type: Poster

Authors

Seidel Leif1, Albuquerque Wendell2, Happel Katharina3, Gand Martin2, Zorn Holger2,3, Schweiggert Ralf1 and Will Frank1

1Department of Beverage Research, Geisenheim University
2Institute of Food Chemistry and Food Biotechnology, Justus Liebig Giessen 
3Fraunhofer Institute for Molecular Biology and Applied Ecology, Giessen, Germany

Contact the author

Keywords

wine colloids, proteins, carbohydrates, molar mass

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

A spatial explicit inventory of EU wine protected designation of origin to support decision making in a changing climate

Winemaking areas recognized as protected designations of origin (PDOs) shape important economic, environmental and cultural values that are tied to closely defined geographic locations. To preserve wine products and wine-growing practices adopted in different PDOs these areas are strictly regulated by legal specifications. However, quality viticulture is increasingly under pressure from climate change, which is altering the local conditions of many winegrowing areas. Therefore, maintaining traditional wine products will require the adoption of tailored adaptation strategies, including possible changes in the legal regulation of protected wines. To this end, it is necessary to have a comprehensive knowledge on PDOs including their extension, products and allowed practices. While there have been efforts to build databases that summarize the characteristics for individual wine PDO areas and to quantify the related effects of climate change, much information is still included only in the official documentation of the EU geographical indication register and has never been collected in a comprehensive manner. With this study we aim at filling this gap by building a spatial inventory of European wine PDOs that supports decision making in viticulture in the context of climate change. To map and characterize European wine PDOs, we analysed their legal documents and extracted relevant information useful for climate change adaptation. The output consists of a comprehensive geographical dataset that identifies the boundaries of all 1200 European wine PDOs at unprecedented spatial resolution and includes a set of legally binding regulations, such as authorized vine varieties, maximum yields and planting density. The inventory will allow researchers to analyse the impacts of climate change on European wine PDOs and support decision makers in developing tailored adaptation strategies. This includes, among others, the evaluation of new vineyard site selection, the expansion of cultivated varieties or the authorization of irrigation in vineyards.

Current climate change in the Oplenac wine-growing district (Serbia)

Serbian autochthonous vine varieties Smederevka (for white wines) and Prokupac (for rosé and red wines) are the primary representatives of typical characteristics of wines and terroir of numerous wine-growing areas in Serbia. In the past, these varieties were the leading vine varieties, however, as the result of globalization of winemaking and the trend of consumption of wines from widely prevalent vine varieties, they were replaced by introduced international varieties. Smederevka and Prokupac vine varieties are characterized by later time of grape ripening, and relative sensitivity to low temperatures. Climate conditions can be a restrictive factor for production of high-quality grapes and wine and for the spatial spreading of these varieties in hilly continental wine-growing areas.
This paper focuses on the spatial analysis of changes of main climate parameters, in particular, analysis of viticultural bioclimatic indices that were determined for the purposes of viticulture zoning of wine-growing areas in the period 1961-2010, and those same parameters determined for the current, that is, referential climate period (1988-2017). Results of the research, that is, analysis of climate changes indicate that the majority of examined climate parameters in the Oplenac wine-growing district improved from the perspective of Smederevka and Prokupac vine varieties. These studies of climate conditions indicate that changes of analyzed climate parameters, that is, bioclimatic indices will be favorable for cultivation of varieties with later grape ripening times and those more sensitive to low temperatures, such as the autochthonous vine varieties Smederevka and Prokupac, therefore, it is recommended to producers to more actively plant vineyards with these varieties in the territory of the Oplenac wine-growing district.

Leaf vine content in nutrients and trace elements in La Mancha (Spain) soils: influence of the rootstock

The use of rootstock of American origin has been the classic method of fighting against Phylloxera for more than 100 years. For this reason, it is interesting to establish if different rootstock modifies nutrient composition as well as trace elements content that could be important for determining the traceability of the vine products. A survey of four classic rootstocks (110-Richter, SO4, FERCAL and 1103-Paulsen) and four new ones (M1, M2, M3 and M4) provided by Agromillora Iberia. S.L.U., all of them grafted with the Tempranillo variety, has been carried out during 2019. The eight rootstocks were planted in pots of 500 cc, on three soils with very different characteristics from Castilla-La Mancha (Spain). In the month of July, the leaves were collected and dried in a forced air oven for seven days at 40ºC. Then, the samples were prepared for the analysis determination, carried out by X-Ray fluorescence spectrometry. The results obtained showed that in the case of content in mineral elements in leaf, separated by soil type, we can report the importance of few elements such as Si, Fe, Pb and, especially, Sr. The rootstock does not influence the composition of the vine leaf for the studied elements that are the most important in determining the geochemical footprint of the soil. The influence of the soil can be discriminated according to some elements such as Fe, Pb, Si and, especially, Sr.

Frost risk projections in a changing climate are highly sensitive in time and space to frost modelling approaches

Late spring frost is a major challenge for various winegrowing regions across the world, its occurrence often leading to important yield losses and/or plant failure. Despite a significant increase in minimum temperatures worldwide, the spatial and temporal evolution of spring frost risk under a warmer climate remains largely uncertain. Recent projections of spring frost risk for viticulture in Europe throughout the 21st century show that its evolution strongly depends on the model approach used to simulate budburst. Furthermore, the frost damage modelling methods used in these projections are usually not assessed through comparison to field observations and/or frost damage reports.
The present study aims at comparing frost risk projections simulated using six spring frost models based on two approaches: a) models considering a fixed damage threshold after the predicted budburst date (e.g BRIN, Smoothed-Utah, Growing Degree Days, Fenovitis) and b) models considering a dynamic frost sensitivity threshold based on the predicted grapevine winter/spring dehardening process (e.g. Ferguson model). The capability of each model to simulate an actual frost event for the Vitis vinifera cv. Chadonnay B was previously assessed by comparing simulated cold thermal stress to reports of events with frost damage in Chablis, the northernmost winegrowing region of Burgundy. Models exhibited scores of κ > 0.65 when reproducing the frost/non-frost damage years and an accuracy ranging from 0.82 to 0.90.
Spring frost risk projections throughout the 21st century were performed for all winegrowing subregions of Bourgogne-Franche-Comté under two CMIP5 concentration pathways (4.5 and 8.5) using statistically downscaled 8×8 km daily air temperature and humidity of 13 climate models. Contrasting results with region-specific spring frost risk trends were observed. Three out of five models show a decrease in the frequency of frost years across the whole study area while the other two show an increase that is more or less pronounced depending on winegrowing subregion. Our findings indicate that the lack of accuracy in grapevine budburst and dehardening models makes climate projections of spring frost risk highly uncertain for grapevine cultivation regions.

Underpinning terroir with data: rethinking the zoning paradigm

Agriculture, natural resource management and the production and sale of products such as wine are increasingly data-driven activities. Thus, the use of remote and proximal crop and soil sensors to aid management decisions is becoming commonplace and ‘Agtech’ is proliferating commercially; mapping, underpinned by geographical information systems and complex methods of spatial analysis, is widely used. Likewise, the chemical and sensory analysis of wines draws on multivariate statistics; the efficient winery intake of grapes, subsequent production of wines and their delivery to markets relies on logistics; whilst the sales and marketing of wines is increasingly driven by artificial intelligence linked to the recorded purchasing behaviour of consumers. In brief, there is data everywhere!

Opinions will vary on whether these developments are a good thing. Those concerned with the ‘mystique’ of wine, or the historical aspects of terroir and its preservation, may find them confronting. In contrast, they offer an opportunity to those interested in the biophysical elements of terroir, and efforts aimed at better understanding how these impact on vineyard performance and the sensory attributes of resultant wines. At the previous Terroir Congress, we demonstrated the potential of analytical methods used at the within-vineyard scale in the development of Precision Viticulture, in contributing to a quantitative understanding of regional terroir. For this conference, we take this approach forward with examples from contrasting locations in both the northern and southern hemispheres. We show how, by focussing on the vineyards within winegrowing regions, as opposed to all of the land within those regions, we might move towards a more robust terroir zoning than one derived from a mixture of history, thematic mapping, heuristics and the whims of marketers. Aside from providing improved understanding by underpinning terroir with data, such methods should also promote improved management of the entire wine value chain.