The valorisation of wine lees as a source of mannoprotein for food and wine application

Wine lees is one of the main winemaking by-products, and still today one of the less valorised, as ethanol and tartaric acid are still the main extracted compounds.  In particular, at the ethanol extraction, what remains is lees yeast biomass (high BOD) usually used as a fertilizer in land-spreading, which can be harmful for soil. Commercial mannoproteins, made from pure yeast biomass, are already present on the market, sold as wine stabilizers and foam enhancers, but are also used as emulsifiers and foaming agents in the food industry.

New ways to valorise this specific fraction, which can contribute to the environmental and economical sustainability of the wine supply chain, has been the focus of different researchers. In Alberto De Iseppi’s quest, the goal was to extract yeast mannoproteins, cell wall polysaccharides localized in the more external layer of the cell wall and evaluate if wine lees can be a novel effective source of mannoproteins for both wine and food applications.

Starting from the application of different extraction methods, two physical (autoclave and sonication) and one enzymatic (Glucanex®, an industrial β-glucanases), the research carries on with the characterization of the obtained extracts and wine applications of all three. What was the impact on tartrate stability, foaming properties and protein stability of these extracts? Which proved to be the best and could be used as an alternative to pure biomass in food application?

Video of the seminar held during Enoforum USA 2021 (4-5 May 2021)