Evaluation of Nonvolatile Flavor Compounds in Vidal Icewine from China

Nonvolatile favor compounds are important for icewine mouthfeel and flavor. Three tiers (ranks) of Vidal icewines from vintages 2008 to 2010 in China were selected for organic acid, amino acid, and phenolic compound analysis by HPLC and UPLC, and a large database on nonvolatile flavor compounds of Vidal icewines was developed. The results revealed similar distribution profiling of nonvolatile flavor compounds among the nine icewine samples. The most abundant organic acids in the icewines were L-malic, tartaric, acetic, and citric, and the principal amino acids were arginine and proline. Hydroxybenzoic acid derivatives were the major constituents of the phenolic acids in the icewines, such as protocatechuic acids, while the hydroxycinnamic acids, such as ferulic acid, were also detected in large amounts. Epigallocatechin accounted for over 80% of total flavan-3-ol content in all icewines. Principal component analysis resulted in satisfactory classifications of vintages. Icewine samples were effectively distinguished in three groups by 2008, 2009, and 2010 vintages. However, the ranks of icewines could not be discriminated by data on amino acids, organic acids, or phenolic compound contents. In sum, the distribution profiling of nonvolatile flavor compounds could be a criterion for identifying icewines of different years.