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…

Adaptation to soil and climate through the choice of plant material

Choosing the rootstock, the scion variety and the training system best suited to the local soil and climate are the key elements for an economically sustainable production of wine. The choice of the rootstock/scion variety best adapted to the characteristics of the soil is essential but, by changing climatic conditions, ongoing climate change disrupts the fine-tuned local equilibrium. Higher temperatures induce shifts in developmental stages, with on the one hand increasing fears of spring frost damages and, on the other hand, ripening during the warmest periods in summer. Expected higher water demand and longer and more frequent drought events are also major concerns. The genetic control of the phenotypes, by genomic information but also by the epigenetic control of gene expression, offers a lot of opportunities for adapting the plant material to the future. For complex traits, genomic selection is also a promising method for predicting phenotypes. However, ecophysiological modelling is necessary to better anticipate the phenotypes in unexplored climatic conditions Genetic approaches applied on parameters of ecophysiological models rather than raw observed data are more than ever the basis for finding, or building, the ideal varieties of the future.

Impact of climate change on the viticultural climate of the Protected Designation of Origin “Jumilla” (SE Spain)

Protected Designation of Origin “Jumilla” (PDO Jumilla) is located in the Spanish provinces of Albacete and Murcia, in the South-eastern part of the Iberian Peninsula, where most of the models predict a severe impact of climate change in next decades. PDO Jumilla covers an area of 247,054 hectares, of which more than 22,000 hectares

Impact of yeast derivatives to increase the phenolic maturity and aroma intensity of wine

Using viticultural and enological techniques to increase aromatics in white wine is a prized yet challenging technique for commercial wine producers. Equally difficult are challenges encountered in hastening phenolic maturity and thereby increasing color intensity in red wines. The ability to alter organoleptic and visual properties of wines plays a decisive role in vintages in which grapes are not able to reach full maturity, which is seen increasingly more often as a result of climate change. A new, yeast-based product on the viticultural market may give the opportunity to increase sensory properties of finished wines. Manufacturer packaging claims these yeast derivatives intensify wine aromas of white grape varieties, as well as improve phenolic ripeness of red varieties, but the effects of this application have been little researched until now. The current study applied the yeast derivative, according to the manufacture’s instructions, to the leaves of both neutral and aromatic white wine varieties, as well as on structured red wine varieties. Chemical parameters and volatile aromatics were analyzed in grape musts and finished wines, and all wines were subjected to sensory analysis by a tasting panel. Collective results of all analyses showed that the application of the yeast derivative in the vineyard showed no effect across all varieties examined, and did not intensify white wine aromatics, nor improve phenolic ripeness and color intensity in red wine.

Green berries on Gewürztraminer (Vitis vinifera L.) in South Tyrol (Italy)

The grape variety Gewürztraminer is known to be affected by two physiological disorders namely berry shrivel and bunch stem necrosis. During the season 2014 we noticed a new symptomatology type of ripening disorder on the variety. The new symptom showed not all berries fallowing the normal maturation stages, but single berries remaining at a soft but green stage till harvest. The broad distribution of these so called “green berries” symptoms in different production sites of our region, caused huge damage due to the difficulty of eliminating single berries per bunch before harvesting. Therefore, the Research Centre Laimburg began to investigate the reasons and origins of this new symptom. This work shows the results of first attempts to find causes for the symptom as well as the resulting approach to mitigate symptoms. Applications of magnesium leaf fertilizer showed first promising results against this putative disorder. To study the causal effect of the green berries 30 symptomatic vineyards in 2014 have been selected for a monitoring during the season 2016. To evaluate the foliar nutrient treatment two vineyards have been selected for application of magnesium sulfate and magnesium chloride. Leaf and berry nutrient analysis, as well as the main quality parameters during ripening have been performed. As soon as “green berries” symptoms appeared, incidence and severity have been evaluated. Most of the symptomatic vineyards of the 2016 monitoring showed light to clear magnesium deficit symptoms on their foliage. Only during the seasons 2020 and 2021 “green berries” symptoms could be found in the leaf fertilizer treatment vineyards. Both seasons showed a significant effect of the magnesium treatments to reduce the incidence and severity of the symptom. It seems that the appearance of the “green berries” symptom on Gewürztraminer is correlated to a disturbed uptake of magnesium of the vines.

A multidisciplinary approach to evaluate the effects of the training system on the performance of “Aglianico del Vulture” vineyards

Vineyards are complex agro-ecosystems with high spatial and temporal variability. An efficient training system may counteract the adverse effects of this variability. Moreover, considering the climate change issues, choosing an efficient training system that enhances water use and protects the vines from radiative thermal stress has become a priority for the farmers. A multidisciplinary approach that assesses the soil-crop-yield-wine relationships of vineyards in a distributed and holistic way could bring added knowledge on the behavior of the different training systems. This ongoing research aimed to implement a multidisciplinary approach to study the behavior of “Aglianico del Vulture” grapevines trained with two different systems: a spurred cordon (SC) and an “Alberello in parete” (AL), grown in a high-quality wine production area of Basilicata region (Italy). The approach merged several methods and scales of soil, ecophysiology, must/wine quality, and spectral data collection to assess the influence of the training system. Homogeneous zones (HZs) in both training systems were defined through a procedure based on geomorphological classification, unmanned aerial vehicles (UAV) images analysis, and a traditional soil survey supported by geophysical scanning. During the 2021 season, TDR probes monitored soil water content, while grapevine health status was assessed using eco-physiological measurements (LWP, chlorophyll content, PSII photosynthetic efficiency, LAI, and point-based field spectroscopy). These grapevine in-vivo measurements validated the spectral vegetation indexes (NDVI, RENDVI, CVI, and TVI) derived from the UAV multispectral imagery, which monitored the grapevine status in a distributed and non-invasive way. Grape yield, quality of berries, must and wine were measured to assess the effects of the training systems. The first experimental year results showed the variability of the vineyards and revealed relationships among soil parameters, crop characteristics, and vegetation indices of the SC and AL training systems. This multidisciplinary study could bring new insights into the vineyard training system’s effects on grape yield and wine quality.