In this post, we are going to talk about the importance of using mannoproteins in winemaking to improve quality, since its application improves the organoleptic perception in terms of sensations of body and volume in the mouthfeel, such as smoothness. In the case of red wines, they reduce the astringency and bitterness of the tannins. In addition, mannoproteins achieve greater aromatic, tartaric, protein and colouring stability.
WHAT ARE MANNOPROTEINS?
Mannoproteins are major components (25-50%) of the cell wall of Saccharomyces cerevisiae yeasts, which, together with other polysaccharides, form part of their structure
They are released during the cell active growth phase and in autolysis, after cell death. Chemically, mannoproteins are proteoglycans containing 5-20% peptide portion and 80-95% mannose sugar chains. Its biological function for yeasts is to provide structure and rigidity to the cell. In addition, they constitute an adaptation mechanism against adverse conditions. Indeed, the quantitative composition of the yeast cell wall is not always the same, but is strongly influenced by the physiological conditions and the age of the cells. Thus, the ratio of glycans to mannoproteins increases with the amount of sugar in the medium. On the other hand, and as is logical, given its protein fraction, the synthesis of mannoproteins is linked to the availability of nitrogen. In any case, the walls of older cells are richer in glucans and chitin (which forms part of the budding scars) and less abundant in mannoproteins than in young cells.
WHAT IS THEIR FUNCTION?
The mannoproteins mainly improve organoleptic perception, helping to improve the body and volume sensations in the mouthfeel in terms of unctuousness. In addition, they contribute to stability in both tartars, by blocking crystallization reactions, and protein and colouring matter, through interaction with tannins and wine proteins. By interacting with the phenolic compounds in red wines, they reduce the astringency and bitterness of the tannins. They also stabilize the aromatic fraction and delay its perception, prolonging the aftertaste. Mannoproteins are therefore very positive for wine quality.
AND HOW DO THEY DO IT?
Their mechanism of action is to act as protective colloids, preventing the aggregation of certain molecules, helping their suspension in the medium and preventing their precipitation. This way, they associate with tartrate crystals and interact with unstable proteins. With regard to the aromatic fraction, they are capable of forming weak bonds with fermentative aromas (esters) and using their protein fraction to bond to varietal aromas (β-ionone) with strong bonds (hydrophobic). It seems that those mannoproteins with a more significant part are more efficient when binding to volatile molecules. In red wines, mannoproteins and polysaccharides help colour stability, associating with polyphenolic compounds, limiting astringency and providing sensations of roundness and volume in the mouthfeel.
MANNOPLUS ND FROM AGROVIN: HOW TO GET A QUALITY WINE USING MANNOPROTEINS
Promoting the mannoprotein content in wines is a useful tool for increasing sensory perceptions in wine and helping wine stability. Working with the fermentation lees requires certain care from the beginning of the alcoholic fermentation to prevent both reduction problems and microbial deviations. There are valid alternatives to help limit risks, by completing or substituting the fermentation lees, such as the use of enzymatic preparations with β-glucanase activity or the application of yeast derivatives, specially prepared to increase the wine mannoprotein content (external lees).
The Agrovin Group has been a pioneer in the design of mannoproteins and has recently formulated a 20% aqueous solution with great competitive advantages over other formulations.
Its called MannoPlus ND and it is a purified mannoprotein in liquid format, prepared for direct application in wine. Its use helps improve the sensory characteristics of the wine, providing density, unctuous sensation and body. It polishes aggressive tannins, reducing astringency. It smooths out the excessive tannins of the wood and restores the acid balance by increasing the positive mouth sensations.
It also improves:
- Tartaric stability, preventing the crystallization of tartaric acid salts.
- Protein stability.
- Colour stability, due to the formation of protective colloids and stable complexes with tannins.
- When applied in a second fermentation, it favours the increase in volume in the mouthfeel and the persistence of the foam.
Due to the organoleptic intervention of the mannoproteins, it provides unctuousness and considerably increases the sensation of volume in the mouth. Fast action on the sensation of volume in the mouth. It does not provide any additional aromatic register to the wine.
HOW IT’S USED
The Agrovin Group technical and advisory team recommends its use for white, red and rosé wines, either in the finished wine as the final treatment before bottling or for wines before they are filtered.
The Mannoplus ND mannoprotein liquid formulation, hardly increases the clogging rate of well-prepared wines and can therefore be used at any stage of the process. It is recommended to know the clogging index prior to passing the wine through microfiltration.
And, finally, for sparkling wines, it is recommended for use during disgorgement or together with the addition of the liquor.