Withering of the ‘Moscato giallo’ grapes under covered space

Malolactic fermentation (MLF) the microbial bioconversion of L-malic acid into L-lactic acid, is a pivotal metabolic process that holds fundamental significance for the quality and organoleptic characteristics of some wines. Oenococcus oeni is considered to be the main player in this conversion, and it is globally used as a starter culture for mlf thanks to his capacity to tolerate the harsh wine environment.

The chemical composition of grape berries at harvest is one of the most important factors that should be considered to produce high quality wines. Among the different chemical classes which characterize the grape juice, the polyphenolic compound, such as flavonoids, contribute to the final taste and color of wines. Recently, an innovative non-destructive method, based on chlorophyll fluorescence, was developed to estimate the phenolic maturity of red grape varieties through the evaluation of anthocyanins accumulated in the berry skin. To date, only few data are available about the application of this method on white grape varieties.

Bentonite fining is commonly used in oenology to remove all or parts of white wine proteins, which are known to be involved in haze formation. This fining is effective, but has disadvantages: it is not selective, thus molecules responsible for aroma are also removed, it causes substantial volume losses, and finally it generates wastes. Over the last decades, the knowledge of wine proteins has increased: they have been identified, their structures are known, some of them have been crystallized.

More frequent and extreme temperatures and droughts pose challenges to the wine sector in Mediterranean Europe. Soil is crucial to sustain the equilibrium of ecosystems, economic growth and people’s prosperity worldwide. In viticulture, soils are a major component of the terroir and do influence vine’s growth, yield and berry composition. Soil temperature (ST) affects soil´s physical, chemical and biological processes and also crop growth. The impact of ST becomes even stronger when dealing with row crops such as grapevine, when considering the increased exposition to radiation. However, the impact of ST on crop performance remains poorly described, especially for extreme climatic conditions.

Wine lees are quantitatively the second most important wine by-product after grape stems and marc [1]. In order to recycle, distilleries recovered ethanol and tartaric acid contained in wine lees but yeast biomass is often unused. It has already been demonstrated that this yeast biomass could be upcycled to produce yeast extracts of interest for wine chemical stabilization [2]. In addition, it is well known that lees, during aging, release compounds that preserve wine from oxidation.