Mgaloblishvili Rpv29 and Rpv31 loci reveal new insights on downy mildew resistance sources in Vitis vinifera

The timing of grape harvest is crucial factor to be considered in the winemaking process, as delayed harvest increases the content of varietal aromas, esters, aldehydes

In Chile there is a dry farming area known as a traditional wine region, where varieties brought by the Spanish conquerors still persist. These varieties, in general, are cultivated under traditional systems, with low use of technical and economic resources, and low profitability for their grapes and wines. In this region, as in other wine grape growing areas, climatic conditions have changed significantly in recent decades. In particular, the occurrence of spring frosts, when bud break has already begun, have generated significant losses for these growers.

Hydroxytyrosol (HT) is a bioactive phenolic compound with antioxidant activity. Yeast synthetise tyrosol from tyrosine by the Ehrlich pathway which is subsequently hydroxylated to HT. The aim of the present work is to develop and validate an UHPLC–HRMS method to assess the metabolites involved in this pathway as well as to screen Spanish commercial wines for HT bioactive compound.

Malolactic fermentation (MLF) is a desired process in red and acidic white wines, after alcoholic fermentation (AF), carried out by the lactic acid bacterium (LAB) Oenococcus oeni. The advantages are an increase of pH, microbiological stabilization and organoleptic improvement of the final wine. However, the presence of stress factors such as ethanol, low pH, high total SO2, lack of nutrients and presence of inhibitors, could affect the successful completion of MLF [1]. Changes in amino acid composition and deficiencies in peptides after AF, showed that MLF can be delayed, signaling its importance for bacterial growth and L-malic acid degradation during MLF [2].

Recent wine-like reconstitution sensory studies confirmed that several monoterpenes were the key aroma compounds in the perception of an ‘apricot’ aroma attribute in Viognier wine.