Andrea Versari

Effect of micro-oxygenation on sensory characteristics and consumer preference of Cabernet Sauvignon wine.

BACKGROUND The main objective of this study was to improve the structure of a Cabernet Sauvignon red wine in a short period of time by micro-oxygenation (MOX) at high rates (25 and 50 mL L(-1) month(-1) ), the effects of which were evaluated based on sensory characteristics and consumer preference. Sensory data were analysed by principal component analysis, discriminant analysis and ordinal logistic regression (OLR). RESULTS MOX led to significant differences in the colour, colour stability and phenolic compounds of wine. Sensory characteristics also changed through MOX treatment, and wine experts were able to discriminate between MOX-treated and untreated samples, with olfactory intensity, complexity, astringency and roundness being the main discriminating characteristics. Ordinal logistic regression enabled identification of the sensory characteristics that drove consumer preference. CONCLUSION MOX at high rates improved the sensory characteristics of wine and may therefore be considered a valid technique for obtaining structured wines in a short period of time, i.e. within just a few months after the vintage. The results highlight the need for (i) careful selection of the MOX dosage rate and duration (the 25 mL L(-1) month(-1) dose for 6 days provided the best result) and (ii) continuous monitoring of the MOX treatment.

Characterization of Uva Longanesi Red Wine by Selected Parameters Related to Astringency

This research represents a first attempt to chemically characterize wines produced from the autochthonous grape variety, Uva Longanesi, based upon the phenolic compounds responsible for its high astringency as confirmed by preliminary sensory analysis. In addition, a wine produced from Sangiovese, the most popular grape variety in the Emilia-Romagna region, was analyzed for comparative purposes. Results showed that Uva Longanesi wine had a higher pH, alcohol concentration, and total dry extract than the Sangiovese wine. With regards to phenolic constituents, the Uva Longanesi wine had higher color parameters and greater concentrations of total phenolics, including monomeric anthocyanins, small polymeric pigments, and tannins. The phenolic composition of Uva Longanesi wine was found to be responsible for the high reactivity of the wine during fining trials.

Mass Spectral Characterization of Uva Longanesi Seed and Skin Extracts

Polyphenolics in grape seed and skin extracts of Uva Longanesi were analyzed at harvest with selected chromatography techniques. Seed extract of Uva Longanesi was characterized by high content of proanthocyanidins (average 49 g/100 g extract), of which 42% was polymeric and ~28% was oligomeric. Epicatechin comprised the primary extension subunit (~75%), whereas catechin predominated as the terminal unit (~67%); epicatechin-gallate was present in both extension (~11%) and terminal subunits (~9%). As skins matured, terminal unit galloylation decreased and extension unit galloylation increased. The mean degree of polymerization of seed proanthocyanidins was relatively constant (average 2.7 subunits) across the sampling dates.