 IVES 9 IVES Conference Series 9 The valorization of wine lees as a source of mannoproteins for food and wine applications

The valorization of wine lees as a source of mannoproteins for food and wine applications

Abstract

AIM. Wine yeast lees constitute a winemaking by-product that, unlike grape skins and seeds, are not sufficiently exploited to add value to the winemaking sector, as their treatment and disposal generally represents a cost for wineries [1]. Recently, some valorization strategies proposed the integrated extraction of ethanol, polyphenols, and tartaric acid, while only a few studies investigated ways to exploit the remaining wine lees’ yeast biomass. In particular, no studies attempted the extraction of mannoproteins (MPs), yeast cell wall polysaccharides with known foaming, emulsifying and wine-stabilizing activities [2], from the wine lees’ yeast biomass. To fill this gap, this research aims at developing an efficient and food-grade method for the extraction of yeast MPs from commercial wine lees, and to test the obtained extracts as wine stabilizers, foaming agents, and food emulsifiers.

METHODS. Several protocols were studied to extract MPs from wine lees. Ultimately, commercial wine yeast lees were extracted at pH 3.4 using an autoclave-based treatment (121°C, 20 min). The obtained MPs extracts were characterized by SEC-HPLC, SDS-PAGE or CI-ELLSA [3]. The functionalities of the MPs’ extracts were tested in wine by assessing their foam-promoting ability and their stabilizing potential against protein and tartrate instabilities. Additionally, MPs extracts were tested as emulsifying and foaming agents in model food matrices. The results were compared to those obtained using commercial MPs-based products and/or MPs extracts from pure cultures of the same yeast strains.

RESULTS. Among the extraction protocols tested, the autoclave emerged as the best performing in terms of extract’s effectiveness and, therefore, it was selected for the subsequent extractions. Firstly, MPs obtained from white winemaking lees positively impacted both wine’s foaming properties (+260% height; +360% stability) and tartrate stability (-11%) compared to untreated wine samples. Conversely, the extracts were ineffective in stabilizing wine against protein haze formation [4]. Subsequently, MPs extracts obtained autoclaving red and white wine lees and tested in model food matrices showed encouraging emulsifying activity (≃55% emulsion stability) and foaming properties (stability >3h). In this case, the extract from red wine lees performed better than its analog derived from the same yeast strain grown in the laboratory, thus suggesting a possible impact of wine polyphenols in enhancing the surfactant action of MPs [5].

CONCLUSIONS

The extraction of MPs from wine lees with a simple and food-grade autoclave-based method can represent an effective valorization strategy that, if integrated with the already available techniques to recover ethanol, tartaric acid, and polyphenols, would result in a better exploitation of this by-product with a consequent improvement of the environmental and economic sustainability of the wine industry.

DOI:

Publication date: September 7, 2021

Issue: Macrowine 2021

Type: Article

Authors

Alberto De Iseppi

Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Italy, Andrea CURIONI1,2; Matteo MARANGON1; Giovanna LOMOLINO1; Simone VINCENZI1,2; Benoit DIVOL3

¹ Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Italy
² Centre for Research in Viticulture and Enology (CIRVE), Conegliano, Italy
³ South African Grape and Wine Research Institute, Stellenbosch University, South Africa

Contact the author

Keywords

wine yeast lees, by-product valorisation, mannoproteins, stability, foam, emulsion

Citation

Can soil water content be used as a predictor of predawn leaf water potential for deficit irrigation scheduling? A case study at Alentejo wine region

Water and heat stress impose new challenges to irrigation management in the Mediterranean areas. This reality has a major impact on the vineyard ecosystem, particularly on the scarce water resources of the Alentejo region (South Portugal). To mitigate this problem, irrigation management should focus on optimizing yield and fruit quality per volume of water applied. This work aims to discuss the use of predawn leaf water potential and soil water status relationships as a decision tool for irrigation management taking as basis data from a field trial where two deficit irrigation strategies were compared.

Smoke tainted wine – what now?

The frequency of bushfires close to wine regions around the world has increased in the last two decades. The economic losses incurred when grapes and wines are discarded due to ‘smoke taint’ are substantial (i.e., hundreds of millions of dollars). Efforts to mitigate and ameliorate smoke taint are therefore crucial. Chardonnay, rosé and cabernet sauvignon wines made from grapes exposed to smoke during the 2020 wildfires in eastern Australia were subjected to various amelioration techniques: the addition of activated carbons, molecularly imprinted polymers (mips), and a proprietary resin (either directly, or following membrane filtration); spinning cone column (scc) distillation; and finally, transformation into vinegar.

Effect of post-harvest ozone treatments on the skin phenolic composition and extractability of red winegrapes cv Nebbiolo and Barbera

Wine industry is looking forward for innovative, safe and eco-friendly antimicrobial products allowing the reduction of chemical treatments in the grape defense and the winemaking process that can affect negatively the quality of the product. Ozone has been tested in food industry giving good results in preventing fungi and bacteria growth on a wide spectrum of vegetables and fruits, due to its oxidant activity and ability to attack numerous cellular constituents. Ozone leaves no chemical residues on the food surface, decomposing itself rapidly in oxygen. Gaseous ozone has been already tested for table grapes storage and on wine grapes during withering.

Caractérisation et gestion de la maturation par terroir en Champagne

Pour prévoir et gérer chaque année les principales caractéristiques de la maturation en Champagne, le CIVC (Comité Interprofessionnel du Vin de Champagne) a développé un ensemble de moyens de prévision et d’information très performants qui permettent aux différents acteurs de la filière viti-vinicole de prendre en compte ces informations à l’échelle de chaque terroir communal pour la recherche d’une qualité optimale.

Rootstock regulation of scion phenotypes: the relationship between rootstock parentage and petiole mineral concentration

Grapevine is grown as a graft since the end of the 19th century. Rootstocks not only provide tolerance to Phylloxera but also ensure the supply of water and mineral nutrients to the scion. Rootstocks are an important mean of adaptation to environmental conditions, because the scion controls the typical features of the grapes and wine. However, among the large diversity of rootstocks worldwide, few of them are commercially used in the vineyard. The aim of this study was to investigate the extent to which rootstocks modify the mineral composition of the petioles of the scion. Vitis vinifera cvs. Cabernet-Sauvignon, Pinot noir, Syrah and Ugni blanc were grafted onto 55 different rootstock genotypes and planted in a vineyard as three replicates of 5 vines. Petioles were collected in the cluster zone with 6 replicates per combination. Petiolar concentrations of 13 mineral elements (N, P, K, S, Mg, Ca, Na, B, Zn, Mn, Fe, Cu, Al) at veraison were determined. Scion, rootstock and the interaction explained the same proportion of the phenotypic variance for most mineral elements. Rootstock genotype showed a significant influence on the petiole mineral element composition. Rootstock effect explained from 7 % for Cu to 25 % for S of the variance. The difference of rootstock conferred mineral status is discussed in relation to vigor and fertility. Rootstocks were also genotyped with 23 microsatellite markers. Data were analysed according to genetic groups in order to determine whether the petiole mineral composition could be related to the genetic parentage of the rootstock. Thanks to a highly powerful design, it is the first time that such a large panel of rootstocks grafted with 4 scions has been studied. These results give the opportunity to better characterize the rootstocks and to enlarge the diversity used in the vineyard.