Aromatics in Three Flavor-type Grapes and Content Changes at Different Growth Stages

  Objective  Contents and changes on aromatics in flavor-type grapes in various stages of fruit development were studied.

  Method  Grapes from Red Globe, Seedless Venus, and Muscat Hamburg varieties were collected for aromatic determination by the headspace solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS).Changes in the contents of major aromatics in 3 growth stages were monitored and analyzed for principal components.

  Result   Methyl salicylate, dimethyl phthalate, dibutyl phthalate, damascenone, and phenylethyl alcohol were the principal aromatic compounds in the fruits of Seedless Venus; linalool, α-Terpineol, geraniol, and geranic acid flavoring compounds, in those of Muscat Hamburg; and (E)-2-hexenal and 1-hexanol, in those of Red Globe.The content of ester aromatics continued to increase along the process of fruit development; the C₁₃ isoprenoids (e.g., damascenone) were the highest in quantity at young stage; the volatiles, e.g., phenylethanol, accumulated from veraison to maturation; the aromatic terpenoids from young to veraison stage; and the C₆ compounds displayed no consistent pattern in the entire growth period.

  Conclusion  The contents and accumulation of aromatics in the varieties of grapes differed significantly. For instance, the aroma of Seedless Venus grapes came mainly from esters, C₁₃ isoprenoids, and other aromatic compounds, with methyl salicylate, dimethyl phthalate, dibutyl phthalate, damascenone, and phenylethyl alcohol being the major contributors.Whereas Muscat Hamburg grapes composed largely of terpenes including linalool, α-Terpineol, geraniol, and geranic acid, while Red Globe consisted of C₆ compounds like (E)-2-hexenal and 1-hexanol.