Free amino acids of leaves and berries of Cabernet Sauvignon grapevines

Abstract

The composition of free amino acids was studied from leaves, pericarps, skins, musts and seeds of Vitis vinifera L. cv. Cabernet Sauvignon. Vineyards were in the Bordeaux region and the grapevines were conducted in espalier and lyre systems. Grapes were collected at maturity and lyophilized after sampling. Extraction of free amino acids was done with a hydroalcoholic solution and their analysis was performed with an autoanalyzer. A standard of 34 amino acids was utilized for the qualitative analysis. The results showed that, for both espalier and lyre training systems, respectively, the free amino acids were predominant in the pericarps (12.85 and 11.21 mg/g dw) - 16.88 and 15.12 mg/g dw in skins and 3.29 and 2.88 g/l in musts -, followed by the seeds (2.37 and 2.32 mg/g dw) and leaves (1.87 and 1.98 mg/g dw). The most abundant free amino acids in leaves were glutamic acid (23.8 and 28.8 p. cent), aspartic acid (8.8 and 11.1 p. cent), and glutamine (10.1 and 9.4 p. cent). Proline (41.8 and 41.5 p. cent) and arginine (22.8 and 22.4 p. cent) predominated in the pericarps. In seeds, the main amino acids were proline (14.5 and 15.8 p. cent), arginine (11.0 and 11.8 p. cent), histidine (11.2 and 8.7 p. cent), and glutamic acid (11.3 and 8.2 p. cent). Grapevine training system showed some differences in the total amount and in the percentages of each free amino acid, but the pattern of these compounds for each tissue was similar for both training systems.