No abstract

This work studies the influence of two different nitrogen sources added to the must on aromatic series and sensory profile of ‘Chardonnay’ wines. Volatile compounds were classified into six odorant series and the total intensities for every aromatic series were calculated as sum of the OAV of each one of the compounds assigned to these series. Sensory profile was defined by quantitative descriptive sensory analysis. The fruity, floral and sweet series are the ones most strongly contributing to the aroma of ‘Chardonnay’ wines, independently of nitrogen source added. In general, the fortification of must with nitrogen source enhances the aroma intensity of wines, especially fruity and floral notes. Samples with organic nutrient presented greater aromatic intensity and more floral aromas than samples with inorganic nutrient. According to the results, the fortification of must with organic nitrogen enhanced the aromatic complexity of wines.

The behaviour in malolactic fermentation (MLF) of an autochthonous strain of Oenococcus oeni, C22L9, isolated from a winery in Castilla-La Mancha (Spain), and of two other commercial strains of O. oeni, PN4 and Alpha (Lallemand Inc.), inoculated by direct inoculation (MBR®) and after a short acclimatisation phase (1-STEP®), was studied. Strain C22L9 carried out MLF slightly faster than the two other commercial strains, leading to a lower increase in volatile acidity and in 2,3-butanedione and 3-hydroxy-2-butanone concentrations, a higher lactic acid content, lower degradation of citric acid and increased degradation of ethanol. No great differences were observed in the duration of MLF, although the acclimatisation cultures were slightly faster, or in the composition of the wines when using the O. oeni strains in the form of MBR® or 1-STEP® cultures. The tasters did not detect significant differences in the wines obtained from the same strain of O. oeni in the two inoculation formats.