IVAS 2022 banner
IVES 9 IVES Conference Series 9 IVAS 9 IVAS 2022 9 The antioxidant properties of wine lees extracts in model wine

The antioxidant properties of wine lees extracts in model wine

Abstract

While the ethanol and tartaric acid contained in wine lees are typically recovered by distilleries, the remaining solid fraction (yeast biomass) is usually disposed of, thus negatively affecting the overall sustainability of the wine industry. Previously we demonstrated that the wine lees’ solid fraction could be submitted to a food-grade physical extraction method (autoclave, 20 min, 121°C) to yield yeast polysaccharides with proven foaming, emulsifying and wine stabilizing properties [1,2]. In this study, the autoclave extraction procedure was applied directly on lees from red winemaking. As a result, two extracts were obtained: the Total extract, namely the whole lees after autoclave containing the soluble and insoluble fractions; the Supernatant, containing only the soluble compounds released during extraction. The composition of the extracts in terms of protein, polysaccharides, glutathione, total thiols, and total polyphenol content, was determined by spectrophotometric and chromatographic analytical methods. Subsequently, the extract’s oxidative behavior was tested by dissolving them (0.5 g/L) in model wine (20% EtOH, 5 g/L tartaric acid, 5 mg/L Fe, 0.5 mg/L Cu) containing 30 mg/L free SO2 and 0.5g/L catechin. The O2 and SO2 consumption, color development (as a function of catechin degradation), and linear sweep voltammetry (LSV) behavior were investigated. The effect of the wine lees’ extracts was benchmarked against analogs extracts obtained from a lab-grown culture of the same yeast strain present in the wine lees. Samples prepared with the wine lees’ extracts showed a higher O2 and SO2 consumption rates compared to those prepared with the lab-grown yeast extracts. All extracts protected the catechin from oxidation, with the best protective action achieved by the Total wine lees extract. This extract, along with its analog from the lab-grown yeast culture, showed the greatest resistance to anodic oxidation according to LSV. The protective action on catechin displayed by all the extracts was not fully explainable by their content in antioxidant compounds as glutathione, thiols, and wine polyphenols. Interestingly, the fact that the best results were obtained using the Total extracts in which both the soluble (released polysaccharides) and insoluble (yeast cell walls) fractions were present, allowed to hypothesize that other compounds are involved in limiting the catechin oxidation. In this scenario, the candidates are the yeast membrane sterols as they possess an oxygen-consuming action, and yeast cell wall polysaccharides as they could bind to catechin thus making it unavailable for oxidation. To conclude, wine lees can be considered a novel source of yeast extract with potential oenological application also against quality-affecting oxidative reactions. If adopted on a large scale,  this wine lees valorization strategy would result in an improvement of the overall sustainability of the wine industry.

References

[1] De Iseppi, A., Marangon, M., Vincenzi, S., Lomolino, G., Curioni, A., & Divol, B. (2021). A novel approach for the valorization of wine lees as a source of compounds able to modify wine properties. LWT, 136, 110274.
[2] De Iseppi, A., Marangon, M., Lomolino, G., Crapisi, A., & Curioni, A. (2021). Red and white wine lees as a novel source of emulsifiers and foaming agents. LWT, 152, 112273.

DOI:

Publication date: June 23, 2022

Issue: IVAS 2022

Type: Article

Authors

De IseppiAlberto1, Curioni Andrea1,2, Marangon Matteo1,2, Invincibile Diletta3, Slaghenaufi Davide3 and Ugliano Maurizio3

1Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale dell’Università, 16, 35020 Legnaro, Padua, Italy
2Centre for Research in Viticulture and Enology (CIRVE), University of Padova, Conegliano, Italy
3Department of Biotechnology, University of Verona, San Pietro in Cariano, Italy

Contact the author

Keywords

wine lees, wine oxidation, voltammetry, wine color, by-product valorization

Tags

IVAS 2022 | IVES Conference Series

Citation

Related articles…

How can historical cultivars mitigate the effects of climate change?

IFV, INRAe and the national network “Partenaires de la Sélection Vigne” representing 37 organizations from the different wine regions, have been working increasingly closely over the last 2 decades towards the preservation of the French varietal patrimony. There are approximately 600 patrimonial varieties according to INRAe and SupAgro Montpellier experts, including ancient cultivars (400) and intravarietal crossbreeds obtained since the 19th century. In the context of a drastic reduction in such varieties from the mid 1980’s in favor of mainstream varieties, it was essential to carry out an inventory of old vines and vineyards. INRAe Vassal collection plays a key role here as it holds the largest diversity available, along with a rich bibliography and herbariums, offering us the opportunity to document and double check the identity of a cultivar, consolidating the expertise of ampelographers. The work is carried out in several stages, from verifying the existence of a variety in a small region, through to rehabilitation. During this session, the authors present the process that leads to the official registration of a variety. After this, IFV selection center takes over to initiate the process of selection and propagation. A specific focus within regions such as the Alps, Champagne and the South-West will provide details of the full procedure. Bia, Bouysselet, Chardonnay rose, Mecle and the aptly named Tardif, are some of the cultivars that have followed this procedure. Furthermore, a recent regulation established by INAO on “varieties of interest for adaptation purposes” might boost uptake by growers. Since 2006, 36 historical cultivars have been registered. Most of these have been neglected in the past due to late maturity, lack of sugar and high titratable acidity at harvest time. Such characteristics are today considered as positive qualities, not only in mitigation of the effects of climate change, but also as an opportunity for restoring diversity…

Effects of organic mulches on the soil environment and yield of grapevine

Farming management practices aiming at conserving soil moisture have been developed in arid and semiarid-areas facing water scarcity problems. Organic mulching is an effective method to manipulate the crop-growing microclimate increasing crop yield by controlling soil temperature, and retaining soil moisture by reducing soil evaporation. In this sense, the effectiveness of different organic mulching materials (straw mulch and grapevine pruning debris) applied within the row of a vineyard was evaluated on the soil and on the vine in a Tempranillo vineyard located in La Rioja (Spain). Organic mulches were compared with a traditional bare soil management technique (based on the use of herbicides to avoid weed incidence). Mulching coverages favourably influenced the soil water retention throughout all the grapevine vegetative cycle. However, the soil-moisture variation was not the same under different mulching materials, being the straw mulch (SM) the one that retained more water in comparison with grapevine pruning debris (GPD) based-cover. The changes of soil moisture in the upper surface layer (0–10 cm) were highly dynamic, probably due to water vapour fluxes across the soil-atmospheric interface. However, both, SM and GPD reduced these fluctuations as compared with bare soils. A similar trend occurred with soil temperature. Both organic mulches altered soil temperature in comparison with bare soil by reducing soil temperature in summer and raising it in winter. Moreover, the same buffering effect for the temperature on the covered soil also remains in the deeper layers. To conclude, we could see that organic mulching had a positive impact on soil-moisture storage and soil temperature and the extent of this effect depends on the type of mulching materials. These changes led to higher rates of photosynthesis and stomatal conductivity compared to bare soils, also favouring crop growth and grape yields.

Heatwaves and grapevine yield in the Douro region, crop model simulations

Heatwaves or extreme heat events can be particularly harmful to agriculture. Grapevines grown in the Douro winemaking region are particularly exposed to this threat, due to the specificities of the already warm and dry climatic conditions. Furthermore, climate change simulations point to an increase in the frequency of occurrence of these extreme heat events, therefore posing a major challenge to winegrowers in the Mediterranean type climates. The current study focuses on the application of the STICS crop model to assess the potential impacts of heatwaves in grapevine yields over the Douro valley winemaking region. For this purpose, STICS was applied to grapevines using high-resolution weather, soil and terrain datasets over the Douro. To assess the impact of heatwaves, the weather dataset (1989-2005) was artificially modified, generating periods with anomalously high temperatures (+5 ºC), at certain onset dates and with specific durations (from 5 to 9 days). The model was run with this modified weather dataset and results were compared to the original unmodified runs. The results show that heatwaves can have a very strong impact on grapevine yields, strongly depending on the onset dates and duration of the heatwaves. The highest negative impacts may result in a decrease in the yield by up to -35% in some regions. Despite some uncertainties inherent to the current modelling assessment, the present study highlights the negative impacts of heatwaves on viticultural yields in the Douro region, which is critical information for stakeholders within the winemaking sector for planning suitable adaptation measures.

Spatial determination of areas in the Western Balkans region favorable for organic production

In problematic conditions for production of grapes and wine caused by the COVID-19 pandemic and the resulting occurrence of wine surpluses, producers are increasingly turning to the innovative viticulture and winemaking of products that are more appealing to the market and the consumers. On the other hand, consumption of the food safety or organic products, and therefore of organic grapes and wine, is increasingly common in the world, in particular in Europe. The Regional Rural Development Standing Working Group (SWG RRD), as a regional intergovernmental organization gathers actors in the viticulture and winemaking sector from states and territories of the Western Balkans (South-East Europe) in the Expert Working Group for Wine, with the aim of improving viticulture and winemaking in this region through joint activities. In accordance with the aforementioned, the SWG RRD is working on advancing organic production of grapes and wine, and on recognition of specificities of the terroir of wine-growing areas in Western Balkans. In addition, as part of the project “Facilitation of Exchange and Advice on Wine Regulations in Western Balkan Countries” helmed by the German Federal Ministry of Food and Agriculture, in addition to harmonization of relevant legislation with EU regulations, efforts are being invested towards recognition of organic wines. Within activities and project implemented by this organization, expert analyses and scientific research of the terroir of Western Balkans were carried out, and some of the results are presented in this paper.

Rapid damage assessment and grapevine recovery after fire

There is increasing scientific consensus that climate changeis the underlying cause of the prolonged dry and hot conditions that have increased the risk of extreme fire weather in many countries around the world. In December 2019, a bushfire event occurred in the Adelaide Hills, South Australia where 25,000 hectares were burnt and in vineyards and surrounding areas various degrees of scorching and infrastructure damage occurred. The ability to coordinate and plan recovery after a fire event relies on robust and timely data. The current practice for measuring the scale and distribution of fire damage is to walk or drive the vineyard and score individual vines based on visual observation. The process is time consuming, subjective, or semi-quantitative at best. After the December 2019 fires, it took many months to access properties and estimate the area of vineyard damaged. This study compares the rapid assessment and mapping of fire damage using high-resolution satellite imagery with more traditional ground based measures. Satellite imagery tracking vineyard recovery in the season following the bushfire is being correlated to field assessments of vineyard productivity such as canopy health and development, fertility and carbohydrate storage. Canopy health in the seasons following the fires correlated to the severity of the initial fire damage. Severely damaged vines had reduced canopy growth, were infertile or had very low fertility as well as lower carbohydrate levels in buds and canes during dormancy, which reduced productivity in the seasons following the bushfire event. In contrast, vines that received minor damage were able to recover within 1-2 years. Tools that rapidly and affordably capture the extent and severity of damage over large vineyard area will allow producers, government and industry bodies to manage decisions in relation to fire recovery planning, coordination and delivery, improving the efficiency and effectiveness of their response.