Grapegrowing soils

During alcoholic fermentation, nitrogen is an essential nutrient for yeast as it plays a key role in sugar transport and biosynthesis of wine aromatic compounds (thiols, esters, higher alcohols). The main issue of a lack in yeast assimilable nitrogen (yan) in winemaking is sluggish or stuck fermentations promoting the growth of alteration species which may lead to economic losses. However, correcting this nitrogen deficiency is sometimes not enough to restore proper fermentation performance. This suggests the existence of other nutritional shortages.

Many microbial starters for the alcoholic and malolactic fermentation processes are commercially available, indicated for diverse wine styles and quality goals. The screening protocols cover a wide range of oenologically relevant features, although some characteristics could also be studied using underexplored powerful techniques. In this study, we applied Fourier Transform Infrared (FTIR) microspectroscopy [1,2] to compare the cell wall biochemical composition and monitor the autolytic process in several wine strains of Saccharomyces cerevisiae.

Establish relationships between taste and mouthfeel properties of grapes and tannin-related chemical parameters. Tempranillo Tinto and Garnacha Tinta grapes were harvested from distinct blocks in different dates; each sample collection date was separated by one week. Grapes were destemmed and macerated in 15% of ethanol for one week. The polyphenolic fraction (PF) of samples was submitted to solid phase extraction on C18 cartridges and recovered with ethanol. PFs were reconstituted in wine model and their taste and mouthfeel properties were characterised by rate-K-attributes methodology. In parallel, concentration (TC) and activity (TAc) of tannins as well as the concentration of tannins linked to anthocyanins (T-A) were determined using HPLC-UV–VIS.

In 2004, at its general assembly, the oiv adopted the transfer of its scientific and technical heritage from the office to the international organisation of vine and wine. Unesco defines heritage as “our legacy from the past, what we live with today, and what we pass on to future generations.”

Phenolic compounds play a central role in sensory characteristics of wine, such as colour, mouthfeel, flavour and determine its shelf life. Furthermore, the major non-enzymatic wine oxidation process is due to the catalytic oxidation of phenols in quinones. Due their importance, during the years have been developed different analytical methods to monitor the concentration of phenols in wine, such as Folin-Ciocalteu method, spectrophotometric techniques and HPLC. These methods can also be used to follow some oxidation-related chemical transformations.