Wine aroma is a complex gaseous mixture composed of various compounds; some of these molecules derive directly from the grapes while most of them are released and synthetized during fermentation or are due to ageing reactions
Yeast mannoproteins and derivates are polysaccharides produced from the cell walls of different yeast strains widely used in the winemaking and finning of wines to improve their overall stability and sensory properties.
Pinking of white wine is an undesired change potentially occurring over storage, leading to the turning of color from yellow into salmon-red hue.
Hydrogen sulfide and methanethiol are recognised as two of the most significant contributors to reductive off-flavours in wine.
Polysaccharides (PS) are one of the main compounds found in wines, and they come mainly from the grape cell walls or from the yeasts, and they play an important role in the technological and sensory characteristics of wines. Polysaccharides obtained from yeasts have been more studied, especially mannoproteins, since there are commercial products.
High temperatures typical of warm climates cause the colour of red wines to become increasingly unstable over time.
Stems may bring various benefits to the wine such as alcoholic reduction, color protection or improvement of the tannic intensity.
Light-induced reactions can be responsible for detrimental changes of white and rosé wines. This is associated to the photo-degradation of riboflavin (RF) and of methionine (Met) causing the appearance of light-struck taste (LST).
Dimethyl sulfide (DMS) is a compound that accumulate in wine for the early years of ageing 1. During this stage, which is often carried out in the bottle, the environmental conditions are conducive to the release of DMS from its precursors, already present in grapes2
Port wine is a fortified wine exclusively produced in the Douro Appellation (Portugal) under very specific conditions resulting from natural and human factors. Its intrinsic aroma characteristics are modulated upon a network of factors, such as the terroir, varieties and winemaking procedures that include a wide set of steps, namely the fortification with grape spirit (ca. 77% v/v ethanol).
Volatile sulfur compounds (VSCs), mainly hydrogen sulfide and methanethiol (H2S and MeSH), are the responsible for reductive off-odor in wine.
Vinification by carbonic maceration (CM) is based in the anaerobic fermentative metabolism also called intracellular fermentation (IF).
Sulfur dioxide is widely used during winemaking as an antioxidant and antimicrobial agent. Bisulfite (HSO3−), the predominant form of SO2 at wine pH, reacts with several wine components forming sulfonated adducts.
A major problem for winemakers is the formation of proteinaceous haze after bottling. Although the exact mechanisms remain unclear, this haze is formed by unfolding and agglomeration of grape proteins, being additionally influenced by numerous further factors.
Anthocyanins are the main pigments present in young red wines, being responsible for their intense red color. These pigment in aqueous solutions occur in different forms in equilibrium that are dependent on the pH
Nowadays, winemaking is dealing with great challenges, notably climate change, disease resistance and low pesticide inputs, desire for more sustainable agricultural productions and permanent changing of consumer preference.
SO2 is the most widely used preservative in the wine industry. However, there are several drawbacks related with the use of SO2 in wine such as its toxicity and the unpleasant odor in case of excess.
The use of elicitors to promote the biosynthesis of secondary metabolites in grapes has been tackled in several reports, however its study linked to nanotechnology is less developed.