Effect of non-wine Saccharomyces yeasts and bottle ageing on the release and generation of aromas in semi-synthetic Tempranillo wines

Abstract

AIM: Explore the variability and contribution of non-wine Saccharomyces yeasts and bottle aging on the release and generation of aromas of semi-synthetic Tempranillo wines, together with an in-depth study of the capacity of these strains to provide good fermentative and oenological qualities.

METHODS: 6 Saccharomyces yeasts strains of different species and origins performed fermentations in semi-synthetic must containing polyphenolic and aroma precursor Tempranillo extract. The resulting wines were subjected to accelerated anoxic aging simulating bottle aging. The aroma compounds released during fermentation and those contained in young and aged wines and must were liquid-liquid extracted and analysed by Gas Chromatography-Olfactometry (GC-O), GC-FID (flame ionization detector) and GC-Mass Spectrometry.

RESULTS: Among the compounds volatilised during fermentation, one of varietal origin was tentatively detected, 4-methyl-4-mercaptopenta-2-one (4MMP). The natural yeasts likely to introduce positive aroma notes to young and aged Tempranillo wines were E1 (S. eubayanus), C3, C2 (S. cerevisiae), K3 (S. kudriavzevii) and U1 (S. uvarum) by the highest production of ethyl esters, lactones, β-ionone and terpenes related to floral and fruity aroma. After aging, β-damascenone, riesling acetal, vitispirane A/B, linanool oxide and massoia lactone were found, nerol was no longer detected and β-linalool was not affected. In addition, there was a modulating effect by the yeasts, increasing or decreasing certain compounds favoured by aging. Regarding this effect, C2 strain excelled due to the large increase in ethyl leucate compared to its young wine and the rest of the aged wines.

CONCLUSIONS: Most compounds were highly increased by aging while yeasts at species and strain level were able to modulate the varietal and fermentative aroma profile differentially in both young and aged semi-synthetic Tempranillo wines.