Bioactive compounds of red grapes from Dão region (Portugal): Evaluation of phenolic and organic profile

Abstract

Objective: To improve the knowledge on the metabolite profile of five red grapes from Dão region (Portugal), concerning to the phenolic characteristics (coloured and non-coloured phenolics) and organic acid composition. Methods: Five red grapes collected from Dão region were studied. The profiles of phenolic compounds and organic acids were estimated by high-performance liquid chromatography with diode-array detection and high-performance liquid chromatography with UV detector, respectively. Results: Totally 24 phenolic compounds were identified, and distributed by several classes: 8 anthocyanins, 1 hydroxybenzoic acid, 4 hydroxycinnamic acids, 1 stilbene, 4 flavan-3-ols, 6 flavonols. Additionally, 10 organic acids were detected in all samples. Total contents of each phenolic class and organic acids amounts varied significantly among the different grape cultivars investigated. The principal components analysis differentiates the Touriga Nacional from the other varieties due to their high contents in anthocyanins, non-coloured phenolics and organic acids. Touriga Nacional is an important red grape cultivar, highly esteemed in Dão region for its ability to produce high quality wines. Conclusions: The results suggest that the red grapes from Dão region present a good composition in bioactive compounds, being important for the production of wines with superior quality.

Keywords

• Vitis vinifera
• Grapes
• Dão region
• Phenolics
• Organic acids