Influence of fertilisation with foliar urea on the content of amines in wine

Abstract

Amines are substances that could cause toxic effects in the consumer. The concentration of amines in wine depends on different factors such as grape variety, vinification conditions and nitrogen fertilisation of the vines. The aim of this work was to study the influence of the application of foliar urea on the concentration of amines in wine. To carry out the study, grapevines of Tempranillo variety were used. These grapevines were treated with foliar urea at two different concentrations: 2 and 4 kg N ha−1. Treatment with foliar urea significantly increased (p < 0.05) the concentration of histamine in the wines compared with the control sample (65% in the treatment with 2 kg N ha−1 and 93% in the treatment with 4 kg N ha−1), reaching higher concentrations than the threshold level where it could provoke toxic effects in the consumer (8–20 mg l−1). On the other hand, treatment with foliar urea did not increase the concentrations of other amines which could be toxic such as tyramine or phenylethylamine, nor amines such as putrescine which could enhance the toxic effect of histamine. In the case of the volatile amines containing secondary amine groups, the concentration of pirrolidine increased by 37% after treatment with 2 kg N ha−1 and 61% after treatment with 4 kg N ha−1.