Author(s):
Moreira, Nathalie 
; Pinho, Paula Guedes de ; Santos, Cristina ; Vasconcelos, Isabel
Date: 2011
Persistent ID: http://hdl.handle.net/10400.14/7515
Origin: Veritati - Repositório Institucional da Universidade Católica Portuguesa
Subject(s): Sulphur compounds; Aliphatic higher alcohols; Ammonium salts; Fermentation; Nitrogen; Yeast nitrogen consumption; White wines
Description
Ammonium salts were added to white grape musts, before alcoholic fermentation, in order to evaluate their influence on the heavy sulphur compound and aliphatic higher alcohol composition of resulting wines. Six grape musts were used (Trajadura, Pedernã, Loureiro, Azal Branco, Avesso and Alvarinho). Ammonium supplementation of Trajadura and Pedernã grape musts, with the highest nitrogen level, did not influence the content of heavy sulphur compounds and aliphatic higher alcohols in wines; however, the addition of ammonium salts to grape musts with low initial nitrogen content, such as Loureiro, Azal Branco and Avesso, led to a higher production of 1-propanol and a lower production of isoamyl alcohols and sulphur compounds, e.g. S-methyl thioacetate, 2-mercaptoethanol, acetic acid-3-(methylthio)propyl ester, 3-mercapto-1-propanol, 4-(methylthio)-1-butanol, 3-(ethyithio)-1-propanol. 3-methylthiopropionic acid and N-3-(methylthiopropyl)acetamide. For Alvarinho grape must, a decrease in sulphur compound concentrations in wines was only observed for 3-methylthiopropionic acid, acetic acid-3-(methylthio)propyl ester and 2-mercaptoethanol.
