Role of phenylalanine in viticulture and enology

Resumen

Total nitrogen in grapes consists of inorganic and organic forms. Ammonia salts and amino acids are the most prevalent form of total nitrogen by weight in grapes. They constitute, except proline under good nitrogen content conditions, the assimilable nitrogen fraction, which is used by the yeast in the fermentation process. Moreover, amino acids are also important because they are precursors of a larger number of compounds in grape and wine. Thus, the phenolic compounds are synthesized by the plant through the flavonoid pathway, starting with phenylalanine as a precursor. This amino acid is also metabolised in the course of the fermentation by the yeasts, producing 2-phenylethanol and 2-phenylethyl acetate, which are important compounds for the wine aromatic quality. Therefore, the foliar application of this amino acid in the vineyard could modify the phenolic and aromatic composition of grapes and wines. In recent years, some studies have been conducted about different treatments in vineyard that modified berry composition. These treatments have been carried out to improve the phenolic compound content and the aromatic quality of grapes and wines. However, the effect of the foliar application of phenylalanine on the composition of grape and wine has recently begun to be studied. For these reasons, this paper reviews the role of phenylalanine in the fields of viticulture and enology, focus on its influence on the phenolic and aromatic quality of grape and wine. © 2015 by Nova Science Publishers, Inc. All rights reserved.