title: Effects of elevated CO2 on grapevine (Vitis vinifera L.): volatile composition, phenolic content, and in vitro antioxidant activity of red wine.
abstract: The impact of elevated carbon dioxide concentration ([CO2]) on the quality of berries, must, and red wine (with special reference to volatile composition, phenolic content, and antioxidant activity) made from Touriga Franca, a native grape variety of Vitis vinifera L. for Port and Douro wine manufacturing grown in the Demarcated Region of Douro, was investigated during 2005 and 2006. Grapevines were grown either in open-top chambers (OTC) with ambient (365 +/- 10 ppm) or elevated (500 +/-16 ppm) [CO2] or in an outside plot. In general, the increase of [CO2] did not affect berry characteristics, especially the total anthocyan and tannin concentrations. However, the total anthocyan and polyphenol concentrations of the red wine were inhibited under elevated [CO2]. The antioxidant capacity of the wines was determined by DPPH, ABTS, and TBARS assays and, despite the low concentrations of phenolics, the elevated [CO2] did not significantly change the total antioxidant capacity of the red wines. Thirty-five volatile compounds belonging to seven chemical groups were identified: C6 alcohols, higher alcohols, esters, terpenols, carbonyl compounds, acids, volatile phenols, and C13 norisoprenoids. Generally, the same volatile compounds were present in all of the wines, but the relative levels varied among the treatments. The effect of elevated [CO2] was significant because it was detected as an increase in ethyl 2-methylbutyrate, isoamyl acetate, ethyl hexanoate, ethyl octanoate, butyric acid, and isovaleric acid concentrations and a decrease in ethyl acetate concentration when compared to wines produced in ambient [CO2] in 2005. In elevated [CO2], wines from 2006 had lower methionol, 1-octanol, and 4-ethylguaiacol and higher ethyl lactate and linalool concentrations. The increase in [CO2] did not significantly affect C6 alcohols, citronellol, carbonyl compounds, and beta-damascenone concentrations. This study showed that the predicted rise in [CO2] did not produce negative effects on the quality of grapes and red wine. Although some of the compounds were slightly affected, the red wine quality remained almost unaffected.
authors.affiliation: Department of Food Science, CITAB-Centre for the Research and Technology of Agro-Environment and Biological Sciences, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal. bertag@utad.pt
authors.forename: Berta
authors.initials: B
authors.lastname: Gonçalves
authors.forename: Virgílio
authors.initials: V
authors.lastname: Falco
authors.forename: José
authors.initials: J
authors.lastname: Moutinho-Pereira
authors.forename: Eunice
authors.initials: E
authors.lastname: Bacelar
authors.forename: Francisco
authors.initials: F
authors.lastname: Peixoto
authors.forename: Carlos
authors.initials: C
authors.lastname: Correia
mesh_terms: D000872:Anthocyanins / Q000032:analysis; D000975:Antioxidants / Q000032:analysis*; D001272:Atmosphere / Q000737:chemistry; D002245:Carbon Dioxide / Q000032:analysis*; D005419:Flavonoids / Q000032:analysis*; D005638:Fruit / Q000737:chemistry; D009812:Odorants / Q000032:analysis*; D010636:Phenols / Q000032:analysis*; D059808:Polyphenols; D027843:Vitis / Q000737:chemistry* / Q000187:drug effects; D055549:Volatile Organic Compounds / Q000032:analysis; D014920:Wine / Q000032:analysis*
chemical_list: D000872:Anthocyanins; D000975:Antioxidants; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D055549:Volatile Organic Compounds; D002245:Carbon Dioxide