Effects of regulated deficit irrigation (RDI) on grape composition in Monastrell grapevines under semiarid conditions

Ochratoxin A (OTA) is a mycotoxin produced by several filamentous fungi infecting grape bunches (Penicillium and Aspergillus spp.), this toxin pass to must when grapes are crushed and later it is found in wine. Following the evaluations of the toxicity of OTA, European Commission Regulations have been promulgated introducing upper limits for OTA concentrations in various commodities (cereals, cereal products, dried vine fruit, coffee, wine, grape juice, baby foods and dietary foods for special medical purposes).

The utilization of non-Saccharomyces yeasts in the wine industry has increased significantly in recent years. Alternative species need commonly be employed in combination with Saccharomyces cerevisiae to avoid stuck fermentation, or microbial spoilage. The employment of more than one yeast starter can lead to interactions between different species with an impact on the outcome of wine fermentation. Previous studies[1] demonstrated that S. cerevisiae elicits transcriptional responses with both shared and species-specific features in co-culture with other yeast species.

During red wine aging, numerous chemical reactions occur, contributing to the modification and enhancement of the wine sensory parameters over time [1].

Glutathione is a natural tripeptide composed of l-glutamate, l-cysteine and glycine, found in various foods and beverages. In particular, glutathione can be found in its reduced (GSH) or oxidized form (GSSG) in must, wine or yeasts¹. Numerous studies have highlighted the importance of GSH in wine quality and aging potential². During winemaking, especially during aging on lees, GSH helps prevent the harmful effects of oxidation on the aroma of the wine³. Nevertheless, the amounts of GSH/GSSG present in wine lees are often unknown and the choice of operating conditions (quantity of lees and aging time) remains empirical.

Tartrates are salts of tartaric acid that occur naturally in wine and lead to sediments that cause consumers’ rejection. There are currently different treatments to prevent its occurrence, with cold stabilization being the most traditional and well-known method.