Microwave treatment of grapes: effect on the must and red wine polysaccharide composition

In red wines the post-MLF SO2 addition is an essential event. It is also the case for the “mutage” during the elaboration of the “liquoreux”. At these moments SO2 plays an antimicrobial action and an antioxidant effect. But at current pH of wines, ensuring a powerful molecular SO2 has become very difficult. Recent work on Brettanomyces strains have also shown that some strains are resistant up to 1.2 mg / L of molecular SO2. It’s also the case of the some Saccharomuces or Zygosaccharomyces strains suitable to re-ferment “liquoreux” wines after the “mutage”.

The chemical composition of wines depends on series of variables such as the type of grape, edaphoclimatic conditions, and viticulture and winemaking practices employed during production. Metallic elements play a significant role during winemaking (e.g. as catalysts of oxidation reactions) and have been previously employed for the classification of wines according to provenance. In this work, we focused on the analysis of metallic elements (K, Na, Ca, Zn, Cu, Fe, Mg, Mn, Ni, Cr, Al, Pb, Cd, Hg, Se, Co, Sn and As) in 145 Chilean wine samples (102 reds and 43 white wines), of seven grape varieties, and five of the major wine producing regions in Chile.

Lanthanides, together with scandium and yttrium, make up the group of Rare Earth Elements (REEs). An official method for analysis of the bioavailable REEs accumulated by plants, depending mainly on soil characteristics, chemical speciation in soil and the specific ability of the plant, is still lacking.

The objective this work has been study the possibility of partially or completely replacing sulphur in the winemaking of white wines through the use of the prefermentative saturation of musts with CO2.

We depict the main features of five viticulture agroclimatic indices for 626 wine growing regions within 41 countries.