Impact of the application of new biostimulants on the aromatic profile of Vermentino grapes (

Biostimulants in viticulture, represent a potential sustainable option against abiotic and biotic threats. Moreover, can trigger an innate immune response that leads to the synthesis of secondary metabolites, key compounds for the organoleptic properties of grapes and wines. In this study, the impact of foliar application of biostimulants, prepared with specific fractions of inactivated yeast, on the aromatic profile of Vermentino grapes grown in Tuscany was investigated. Two different products were compared, applied two or three times during veraison, in two years characterized by hot and dry summers. The qualitative and quantitative determination of the aromatic composition of the grapes was carried out using gas chromatography coupled with mass spectrometry (GC-MS). Generally, in treated plants, the sugar content was lower compared to the control. The treatments favoured the content of aromatic precursors in the grapes, particularly terpenoids; in the first year, when applied at three different times during veraison, and in the following year, when applied twice. The effect of biostimulants was positive but varied depending on the frequency of application, the vintage year conditions, and the chemical class of the compounds. Further research is needed to optimize the application of this kind of biostimulants to counteract stress conditions and maintain high grape quality.