Effects of Nitrogen Fertilization of Grapevines on Amino Acid Metabolism and Higher-Alcohol Formation during Grape Juice Fermentation

Abstract

The nitrogen nutritional status of the grapevine can have a determining effect on higher-alcohol (n-propanol, isobutanol, isoamyl alcohol, and active amyl alcohol) concentrations in wine fermented from the juice. Concentrations of key amino acids (valine, leucine, and isoleucine) and others were measured in grape juice and wine made from Thompson Seedless grapes grown under several levels of nitrogen fertilization. Lower levels increased isobutyl, active, and isoamyl alcohol production, and lowered n-propanol production. Above nitrogen fertilization at about 112 kg/ha, higher-alcohol concentrations in the wine changed negligibly.