Impact of crop load management on terpene content in gewürztraminer grapes

The purpose of the study was to monitor berry development as a function of site, vine water status and climate in order to improve our understanding of the role played by climate change on secondary metabolites relevant to wine quality.

Winemaking is influenced by micro-organisms, which are largely responsible for the quality of the product. In this context, Non-Saccharomyces and Saccharomyces species are of great importance not only because it influences the development of alcoholic fermentation (AF) but also on the achievement of malolactic fermentation (MLF). Among these yeasts, Torulaspora delbrueckii allows in sequential inoculation with strains of S. cerevisiae shorter MLF realizations [5] . Little information is available on the temporal effect of the presence of T. delbrueckii on (i) the evolution of AF and (ii) the MLF performance.

Ellagitannins are the main oak wood phenolic compounds that contribute to wine and spirits organoleptic quality (color, astringency, bitterness)(1-3). Given the lack of knowledge regarding their composition and evolution in spirits, the objectives were to follow their extraction kinetic in Cognac “eaux-de-vie” matured in barrel representing different toasting and to observe their evolution and structural modifications during aging. METHODS: Eight different toasting levels were used for studying the impact of the toasting on ellagitannins composition. Two verticals (1978-2018) of “eaux-de-vie” samples coming from two terroirs were analyzed in order to observe ellagitannins evolution during aging. The above analyses were conducted using HPLC-Triple Quadrupole mass spectrometer (4) and the unknown compounds were identified by UPLC-Q-TOF, purified by preparative HPLC prior to 1D/2D-NMR analysis.

Favoring the formation of volatile compounds and their precursors in must and wine represent one of the principal goals during winemaking technology. In recent years, most attention has been placed on using glycosidases to enlarge the aroma profile of white wines. The effect of enzymes makes odorless glycosidically-bound precursors be converted into aromatic compounds. This paper focuses to study the influence of enzymes (pectolytic and β-glycosides) administered before alcoholic fermentation, even if most studies analyze their use in different winemaking stages. Two semi-aromatic varieties such as Fetească regală and Sauvignon blanc were chosen.

Mannoproteins (MPs) with different structure of their polysaccharide part (branching, substitutions, …) were used to better understand the impact of characteristics of the usual structure of MPs when interacting with Grape Seed Tannins (ST).