Indole Content Profiling During Biological Ageing of Cava Sparkling Wine

Indoles are bioactive components found in wine products and are associated with yeast activity. Cava, a Spanish sparkling wine, is characterized by aging in contact with lees, making it a potential matrix for indoles. Therefore, the aim of this study was to determine the indole content in Cava produced at an industrial scale. Nine indoles were analysed by Ultra High-Performance Liquid Chromatography-Tandem Mass Spectrometry in Cava samples with different ageing times (n = 74). Significant amounts of tryptophan (2.3-1680.4 μg/L), tryptophan ethyl ester (0.1-5.2 μg/L), 5-methoxytryptophol (0.3-29.2 µg/L) and n-acetyl serotonin (0.3-2.3 μg/L) were determined. Tryptophan and tryptophan ethyl ester were positively correlated and decreased with ageing time. In fact, a concentration of less than 0.56 μg of the latter indole can become a marker of the most aged Cavas. The ageing time in contact with lees seems to play a key role affecting the indole content, since base wines show high amount of tryptophan and tryptophan ethyl ester while aged sparkling wines have values around the lower 95% confidence limit. Notably, the identification of tryptophan ethyl ester as a potential marker for aging in Cava suggests a new avenue for further research and quality assessment in its production.