Within a research project for simulating the nitrogen turnover in vineyard soils and the nitrogen uptake by the grape vine, a previously developed plant growth model (Nendel and Kersebaum 2004) had to be evaluated. A dataset was obtained from a monitoring experiment at three vineyard sites with different soil types, conducted in the years 2003 and 2004.

Mannoproteins (MPs) are proteoglycans from the outmost layer of yeast cell walls released into wine during alcoholic fermentation and ageing on lees processes. The use of commercial preparations of mannoproteins as additives to improve wine stability with regards to the crystallization of tartaric salts and to prevent protein haze in the case of white and rosé wines is authorized by the OIV.
Regarding red wines and polyphenols, mannoproteins are described as able to improve their colloidal stability and modulate the astringent effect of condensed tannins. The latter interact with salivary proteins forming insoluble aggregates that cause a loss of lubrication in the mouth and promote a drying and puckering sensation. However, neither the interaction mechanisms involved in mannoproteins capacity to impact astringency nor the structure-function relationships related to this property are fully understood.

The main objective is to unravel the yeast biosynthetic pathways for MEL, SER and HT by using the respective labelled amino acids precursors: 15N2-L tryptophan and 13C-tyrosine.
The alcoholic fermentation experiments are performed with two different commercial
S cereviseae yeasts using synthetic must with the addition of the labelled compounds and the bioactive compounds were followed during the fermentation process. Six biological replicates of the fermentations were considered. MEL, SER and HT were analysed by UHPLC coupled to High Resolution Mass Spectrometry (HRMS). Accurate mass determination allowed to unequivocally distinguishing labelled and unlabelled compounds.

Perceived aroma plays an important role in wine quality, and it depends mainly on the volatile composition. Volatile organic compounds (VOCs) from grapes and those formed during winemaking are involved in the sensory complexity of wines. In aroma-neutral winegrape varieties, the winemaking process itself, and particularly alcoholic fermentation (AF), impacts strongly on the organoleptic characteristics of wines due to the formation of volatile alcohols, acids, and esters. In addition, phenolic compounds could contribute not only to the wine color but also to VOCs evolution during AF.

The aim of this work was to study the trapping capacity of four polyaniline polymers towards phenolic compounds in wine-like model solutions. METHODS: The model wine solution was composed of 12% (v/v) and 4 g/L of tartaric acid adjusted to pH = 3.6. A series of centrifuge tubes (15 mL) were filled with 10 mL of model solution enriched with 50 mg/L of five phenolic compounds (i.e., Gallic acid, caffeic acid, (+)-catechin, (-)-epicatechin, and rutin), and treated with different doses of PANI polymer (i.e., 0, 2, 4 and 8 g/L). After the addition of the polymer, the samples were stirred using a platform shaker at room temperature (20 ºC) for 2, 8, 16 and 24 h. All treatments included three replications.