Nitrogen is one of the fundamental elements for the plant, because it promotes its growth and vigor [1]. Moreover, this element is directly involved in the growth of yeasts during fermentation, may even cause sluggish or stuck fermentations [2], so that nitrogen fertilization is important to ensure growth of the vine and a correct composition of the grape and wine. Currently, there are new fertilization techniques such as foliar fertilization, due to assimilation fast and efficient way of products applied to plants [3]. Grape aroma consists of several hundred volatile compounds belonging to different chemical families, being the most important terpenes, C13 norisoprenoids, benzenoids, esters, and C6 compounds. The aim of this work was to study the effect of foliar application of phenylalanine and urea, at two different doses, on the aromatic grape composition. Therefore, to carry out the foliar treatments, aqueous solutions were prepared with the corresponding concentration of phenylalanine (Phe), and urea (Ur). Control plants were sprayed with water solution. The treatments were applied to grapevine twice, at veraison and one week later. The total amount applied in each treatment was 0.9 kg N/ha for Phe1 and Ur1 and 1.5 kg N/ha for Phe2 and Ur2. Treatments were carried out in triplicate. Grapes were analyzed by HS‐SPME‐GC‐MS in order to determine their volatile composition [4]. The results showed that phenylalanine treatment at low dose as nitrogen source improved the presence of esters and benzenoids, decreased the content of terpenoids and C6 compounds, while its effect on C13 norisoprenoids did not show a clear trend. For the urea treatment at low dose the content of all compounds increased, except C6 compounds. The same happened when the highest dose of phenylalanine was applied, showing that the presence of all compounds increased in the grapes, except C6 compounds. For the higher dose of urea, the content of terpenenoids, C13 norisoprenoids and esters increased while benzenoids and C6 compounds decreased. Consequently, the best results were obtained when the highest doses of both nitrogen sources were used, being urea the best treatment to improve the grape aromatic composition.

Póster presentado en la XVI Reunión Científica de la Sociedad Española de Cromatografía y Técnicas Afines (SECyTA 2016), celebrada en Sevilla del 2 al 4 de noviembre de 2016.

Peer Reviewed