Sensory, olfactometric and chemical characterization of the aroma potential of Garnacha and Tempranillo winemaking grapes.

Reconstituted polyphenolic and aromatic fractions (PAFs) from 33 different Garnacha and Tempranillo grapes were incubated in strict anoxia (75 °C × 24 h). Obtained hydrolyzates were characterized by sensory analysis, gas chromatography-olfactometry (GC-O) and gas chromatography-mass spectrometry (GC-MS). Five different aroma categories emerged. Garnacha may develop specific tropical/citrus fruit, kerosene and floral and Tempranillo toasty-woody and red-fruit characteristics. Those notes seem to mask alcoholic and fruit-in-syrup descriptors and the common vegetal background. Twenty-seven odorants were detected by GC-O. GC-MS data showed a clustering closely matching the one found by sensory analysis, suggesting the existence of five specific metabolomic profiles behind the five specific sensory profiles. Overall results suggest that 3-mercaptohexanol is responsible for tropical/citrus fruit, TDN for kerosene, volatile phenols for woody/toasty, β-damascenone and massoia lactone, likely with Z-1,5-octadien-3-one for fruit-in-syrup and alcoholic notes. Nine lipid-derived unsaturated aldehydes and ketones may be responsible for the vegetal background.