Aroma quality of fortified wines from different Moscato cv. cultivated in Sicily

AIM: Vitis vinifera L. cv. Moscato includes different varieties, mainly white grapes with a medium-sized berry, spheroidal or slightly flattened in shape, yellow greenish color which becomes golden yellow or amber when exposed to the sun. Moscato varieties are mainly used for the production of sweet aromatic wines: Fortified, Sfursat and Passito Moscato wines are present on the market.

Despite the increasing interest in sweet dessert wines, at the best of our knowledge, limited data are reported in literature on the composition of Moscato wines especially as regards the aroma volatile constituents which are determinant for the sensory features.

In this context, the research aimed to verify the aroma quality of fortified wines produced from different Moscato varieties, not present in the Sicilian ampelographic panorama, in comparison with Moscato Bianco already grown on the island. A great attention has been given to the amount of terpenes, key aroma compounds for Moscato wines.

METHODS: Grapes of Vitis vinifera L. cv. Moscato of the different varieties (Giallo, Ottonel, Petit Grain, Rosa, Cerletti, Bianco Zucco and Bianco), were cultivated in the experimental vineyard of the Sicilian Wine and Oil Regional Institute (IRVO) located in Partinico (Sicily, Italy); grapes of Moscato Bianco variety were also harvested in the IRVO experimental vineyard located in Noto (Sicily, Italy), the area in which the Moscato Bianco DOC is produced. The phenological, vegetative-productive and fertility data were collected. The protocol to produce fortified wines was the same for all the varieties; the fermentation was stopped when the residual sugar content of must was about 100 g/L by adding 6g/hL of sulfur dioxide and ethanol (95% v/v) up to a total alcohol content of about 15% v/v. Physico-chemical analyses will be carried out on grapes and wines according to the EEC Official Method. Wine volatile aroma compounds were analysed by Headspace Solid Phase Microextraction Gas Chromatography Mass Spectrometry (HS-SPME-GC-MS).

RESULTS: Among the studied varieties, Moscato Giallo showed the highest productivity (P<0,05) whereas Ottonel the lowest. As regards the wine aroma profile, several volatiles have been identified and quantified, both fermentation and varietal aromas. The volatile profiles of the wines from the different varieties showed statistically significant differences mainly regarding the quantity of the varietal aromas, when compared with that one of the Moscato Bianco of Noto. Moscato Rosa wines evidenced a distinctive aroma profile especially as regards the ratio between varietal aromas (floral notes) and esters (fruity notes).

CONCLUSIONS: The results obtained allowed to characterize the behavior of different Moscato varieties in the Sicilian pedoclimatic environment both as regards productivity, and oenological aspects and wine aroma quality. Among the studied varieties, Moscato Rosa cv stands out above all for the peculiarity of its aroma.