Off-Vine Grape Drying Effect on Volatile Compounds and Aromatic Series in Must from Pedro Ximénez Grape Variety

Changes in 36 volatile compounds of must from ripe grapes dried by direct exposure to sun and
must from ripe grapes were studied. Compounds not dependent on sampling site in both musts were
selected, and their concentration/Brix degree ratio values, were subjected to variance analysis. Only
butan-1-ol and isoamyl alcohols showed no differences, while (E)-hex-3-en-1-ol, (Z)-hex-3-en-1-ol,
(E)-hex-2-en-1-ol, (E)-hex-2-enal, hexanoic acid, isobutanol, benzyl alcohol, 2-phenylethanol, γ-butyrolactone, γ-hexalactone, and 5-methylfurfural, showed significant differences between the two must
types, which may be ascribed to the drying process. An approach to describe must odor has been
carried out by grouping volatile compounds in aromatic series, increasing their values in the fruity,
solvent, sweet, and roasted series and diminishing the herbaceous as a consequence of the drying
process.
Keywords: Volatiles; aroma; musts; off-vine grape drying; Pedro Ximénez