Water and nutritional savings shape non-structural carbohydrates in grapevine (Vitis vinifera L.) cuttings

Melatonin is a bioactive compound present in foods and beverages such as wines. During alcoholic fermentation, yeast transforms tryptophan into certain indole compounds, including melatonin. This paper aims to develop and validate a free solvent analytical method by ultra-high performance liquid chromatography coupled with high resolution mass spectrometry (UHPLC/MS-MS) to determine melatonin and its precursors (L-tryptophan, tryptamine, serotonin, tryptophol, N-acetylserotonin, 5-hydroxytryptophan, and 3- indoleacetic) that appropriately prevent the matrix effect.

The barrel-making process is widely recognized as a crucial practice that affects the composition of barrel-aged wine. After the drying process, the staves are considered ready for barrel assembly, which includes the processes of bending and toasting the barrel structure. Toasting is considered one of the most critical stages in determining the physical and chemical composition of the staves, which can influence the chemical and sensory composition of the wine aged in barrels made from them [1].

Ozone is a potent oxidizing compound that quickly decomposes into oxygen without residues. Previous works reported that ozone is not only a disinfectant that directly harms the pathogens of the vine but also activates systemic defense systems in the plant by activating oxidative stress. We assume these systemic defense mechanisms are essential to the vines’ resistance to downy and powdery mildew (Plasmopara viticola & Erysiphe necator, respectively). The goals of the research are to examine the effect of spraying with ozone water on the plant’s resistance against the mentioned pathogens as well as to characterize the metabolic profile of the plants treated with ozone as well as physiological characteristics in the vines such as the level of Photosynthesis and crop yield. Vines in the vineyard sprayed with ozone water at concentrations of 2 and 4 PPM weekly and biweekly, untreated control & conventional spray. Leaves were taken from vines 2,4,7,9 and 11 days after exposure to ozone and inoculated with the pathogens.

Based on historical vine cultivation, the recent development of wine production in Drama wine region (Greece) has led to vine cultivation expansion of white and red varieties. The current cultivation of 500 ha of vineyards is expected to increase in the coming years. Natural terroir units (NTU) have been designed recently to support the production of high quality wines in the region [1]. The aim of this work is to evaluate the relevancy of the proposed NTUs regarding their suitability to produce wines of specific sensorial identity, and to provide guidelines for correct site selection for the expanding wine industry of the region.

Antagonistic yeasts applied to wine grapes must be compatible with the thereafter winemaking process, avoiding competition with the fermentative Saccharomyces cerevisiae or affecting wine flavour. Therefore, fifteen epiphytic yeasts (6 Metschnikowia sp., 6 Hanseniaspora uvarum, 3 Starmerella bacillaris) previously selected for its biocontrol ability against Alternaria on wine grapes were evaluate for possible competition with S. cerevisiae by the Niche Overlap Index (NOI) employing YNB agar media with 10 mM of 17 different carbonate sources present in wine grapes (proline, asparagine, alanine, glutamic acid, tirosine, arginine, lisine, methionine, glicine, malic acid, tartaric acid, fructose, melibiose, raffinose, rhamnose, sucrose, glucose).