During alcoholic fermentation, acetaldehyde is the carbonyl compound quantitatively the most produced by yeasts after ethanol. The dynamics of acetaldehyde production can be divided into 3 phases. Early formation of this compound is observed during the lag phase at the beginning of fermentation before any detectable growth [1].

The under-way zoning works of the Emilia viticulture have pointed out a huge variability of the features of the soils, which belong to this area.

To our knowledge all the studies about laccase kinetics and its inhibition have been performed with substrates and conditions very different from those of real grape juice. Moreover, none of these researches really measure enzymatic browning, since they have not taken into account what happens after the oxidation of o-diphenols in o-diquinones and their subsequent polymerization to form melanins1. For that reason, the aim of this research was to develop a new model to measure the kinetics of browning caused by Botrytis cinerea laccase under conditions much closer to those of grape juice and using the substrates naturally present in it.

Wine aroma is influenced by various factors, from agricultural practices in the vineyard to the enological choices made by winemakers throughout the vinification process. Spontaneous fermentations have a characteristically deeper complexity of aromas when compared to fermentations that have been inoculated with Saccharomyces (S.) cerevisiae because of the diversity of microflora naturally present on grape skins. Non-Saccharomyces yeast are being extensively studied for their ability to positively contribute to wine aroma and flavour. These yeasts are known to liberate more bound volatile compounds present in grape must than S. cerevisiae through the enzymatic action of β-glucosidases and β-lyases1.

Aims: To investigate the intraregional variation of varietal thiol precursors and free thiols in Sauvignon blanc grape juices and experimental wines arising from the Adelaide Hills Geographical Indication (GI) in South Australia.