Headspace-SPME applied to varietal volatile components evolution during Vitis vinifera L. cv. 'Baga' ripening

Grape berries of Vitis vinifera L. cv. Baga were collected during 7 weeks since half-veraison to a post-maturation stage. Two vineyards in different locations in Bairrada Appellation, Pedralvites (Ped) and Colegio (Col) were used. The free varietal and pre-fermentative related volatile compounds that arise in the first 2 h after crushing the grapes were followed by Headspace-Solid Phase Microextraction (HS-SPME). Twenty-three sesquiterpenoids, 13 monoterpenoids, 6 norisoprenoids, 2 aromatic alcohols, and I diterpenoid were detected in both vineyards. However, 40 sesquiterpenoids and 10 norisoprenoids were detected in Ped. The maximum gas chromatographic peak area was reached at the maturity, and remained constant until post-maturation. At maturity sesquiterpenoids represented 56% and 80% of the total. varietal GC peak area in Col and Ped, respectively, which was the group with higher number of constituent varietal compounds. The results obtained indicated a high number of sesquiterpenoid compounds, namely (+)-cycloisosativene, gamma-elemene, alpha-ylangene, beta-bourbonene, beta-cubenene, beta-caryophyllene, 3,7-guaiadiene, (-)-isoledene, (+)-aromadendrene, alpha-amorphene, (-)-delta-selinene, germacrene D, epizonarene, beta-cadinene, gamma-cadinene, delta-cadinene, alpha-muurolene, alpha-calacorene in 'Baga' ripe grapes, which allows to suggest that this variety is a potential source of sesquiterpenoids. (c) 2005 Elsevier B.V. All rights reserved.