Sensory and Olfactometric Profiles of Red Wines after Natural and Forced Oxidation Processes

The aromatic profiles of different Spanish red wines undergoing natural and forced oxidation were examined using sensory, gas chromatography/olfactometry (GC/O), and quantitative analyses. A significant increase in oxidation descriptors such as cognac/brandy/sherry wine or old wine/matured wine was observed after wine oxidation, and wines also lost some of their herbal, fresh, fruity, and flowery notes. This change in the aroma profile was linked to an increase in compounds such as methional, (Z)-2-nonenal, (E)-2-octenal, furaneol, dodecanal, (Z)-whiskey lactone, and o-aminoacetophenone and a decrease of some volatiles with herbal, fruity, and flowery descriptors, such as (Z)-3-hexenol, ethyl hexanoate, and isoeugenol. Quantitative analyses confirmed the importance of aldehydes in the oxidation processes, especially in forced oxidations, where most of the aldehydes reached very high concentrations, such as methional (83.6 μg/L), phenylacetaldehyde (90.2 μg/L), furfural (183.7 μg/L), 5-hydroxymethylfurfural (89.9 μg/L), and 2-methylpropanal (197.7 μg/L).