Study of Intact Glycosidic Aroma Precursors in Recovered Minority White Grape Varieties under Water Stress Conditions

The identification of viticultural strategies capable of mitigating the effects of climate change, including increased temperatures and reduced water availability, has prompted renewed interest in minor grapevine varieties adapted to specific growing areas. The enological suitability of these cultivars depends, in part, on the characterization of their glycosylated aroma precursors. In this study (2022 harvest), two recovered white grape varieties from Castilla-La Mancha, Pintada and Jarrosuelto, were evaluated. Their adaptability to two water stress regimes (moderate/deficit and severe/survival) was evaluated through the composition of intact aroma precursors compared with the predominant regional cultivar, Airén. The results revealed cultivar-dependent responses to water stress. Aroma precursor biosynthesis in Airén was only marginally affected, whereas Pintada exhibited enhanced accumulation under severe water deficit. Additionally, a C₁₃-norisoprenoid hexose-hexose derivative and an isopropyl alcohol pentosyl-hexoside isomer were detected exclusively in Airén and Jarrosuelto, respectively, indicating their potential as varietal markers.