Abstract:Developed from crosses between Vitis vinifera and North American Vitis species, interspecific hybrid grape varieties are becoming economically significant in northern areas, where they are now extensively grown for wine production. However, the varietal differences between interspecific hybrids are not well defined, nor are the relationships between hybrid grape and wine composition, which causes significant drawbacks in the development of viticulture and winemaking of northern wines. In an effort to increase our understanding of interspecific hybrids, we have characterized the free volatile compounds profiles of berries (juice and skin) and wines of five red hybrid varieties (Frontenac, Marquette, Maréchal Foch, Sabrevois and St. Croix) grown in Québec (Canada), using GC-MS(TOF)-SPME. In grapes and wines, significantly higher levels of C6 and other fatty acid degradation products (FADP) were found in Frontenac, Maréchal Foch and Marquette. Terpenes were primarily located in the skin, with Marquette showing the highest level for these compounds. Both the level of terpenes and the level of FADP in grape were strongly correlated with their respective levels in wine, as demonstrated by the redundancy analyses. Nonanal, (E,Z)-2,6-nonadienal, β-damascenone, ethyl octanoate and isoamyl acetate showed the highest OAVs in the wines of the studied varieties.

Viticulture and wine production in challenging environments such as cold and humid areas has substantially expanded in recent years, mostly due to the development of grapevine varieties that show high resistance to fungal diseases and cold temperatures. These interspecific hybrid Vitis (IHV) varieties result from multiple crosses between Vitis vinifera varieties and North American native species such as V. riparia and V. labrusca. Limited scientific information is available on the aroma and winemaking of IHV, and about the relationships between grape and wine composition in regard to compounds of enological interest. In this work, the profile of volatile compounds of grapes and wines from five white IHV varieties largely grown in cold-climate viticulture (Frontenac blanc, Frontenac gris, Seyval, St. Pepin and Vidal) was determined by GC-MS-SPME. Compound classes detected in juice and wine included fatty acid degradation products that represented the largest part of volatile compounds, fatty acid ethyl esters, terpenes, C 13 -norisoprenoids, and volatile phenols and other phenyl derivatives. The flavor profile of Vidal showed the largest diversity of compounds in both juice and wine, and the overall highest amount of volatile compounds of all varieties. Principal component analysis showed relationships between the presence of certain C 6 compounds, terpene and volatile phenols in musts and in the finished wines.

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