Application of Elicitors, as Conventional and Nano Forms, in Viticulture: Effects on Phenolic, Aromatic and Nitrogen Composition of Tempranillo Wines

Abstract

The phenolic, aromatic and nitrogen composition of a wine determines its organoleptic profile and quality. Elicitors have been used as a tool to stimulate the plant’s defense systems, favoring the synthesis of secondary metabolites. In this pioneering study, the elicitor methyl jasmonate in conventional form (MeJ) and in nanoparticle form (ACP-MeJ), with a concentration ten times lower, was applied in a Tempranillo vineyard over two seasons. The phenolic, nitrogen and volatile composition and the sensory properties of the MeJ-based wines were determined. The results showed that the effects of foliar applications of MeJ modify the wine composition. Thus, although the total concentration of most of the groups of phenolic compounds was not altered, several compounds, such as petunidin-3-glucoside, quercetin-3-glucoside, epigallocatechin and most of the stilbenes, increased, in both years, in the treated wines. Amino acids were influenced differently in each of the years studied, and volatile compounds generally did not improve in the treated wines. However, the ACP-MeJ wines were the best rated by the tasters, highlighting their equilibrium on the taste and their genuineness and odor quality. Therefore, foliar applications of ACP-MeJ can be considered a useful tool to improve wine quality.

Influence of foliar treatments with methyl jasmonate and methyl jasmonate-doped nanoparticles on nitrogen composition of Tempranillo grapes during two vintages

“…In 2019, the content of alcohols in the control wines was higher than that of the wines from the MeJ and ACP-MeJ treatments [8], which was probably due to the fact that the sugar content was higher in the control must (Table 1), indicating that the main route of formation of these compounds was the anabolic pathway. Since there were no differences in sugar content between MeJ and ACP-MeJ must samples (Table 1), the differences, respect to the control wines, in the content of alcohols were higher in MeJ than in ACP-MeJ wines [8], probably due to the higher content of amino acids in the MeJ musts (Table 2). However, in 2020, as there were no differences in the sugar content between the control musts and those treated with MeJ and ACP-MeJ (Table 1), practically no differences were observed in the content of higher alcohols in the wines [8], and when there were differences, their content in MeJ wines was lower, since these musts had a lower content of several amino acids (Table 2).…”

“…Higher alcohols can be formed anabolically from sugars as well as catabolically from amino acids via the Ehrlich pathway [27]. In 2019, the content of alcohols in the control wines was higher than that of the wines from the MeJ and ACP-MeJ treatments [8], which was probably due to the fact that the sugar content was higher in the control must (Table 1), indicating that the main route of formation of these compounds was the anabolic pathway. Since there were no differences in sugar content between MeJ and ACP-MeJ must samples (Table 1), the differences, respect to the control wines, in the content of alcohols were higher in MeJ than in ACP-MeJ wines [8], probably due to the higher content of amino acids in the MeJ musts (Table 2).…”

“…This nanoelicitor has been applied in the vineyard of two red grape varieties, Monastrell and Tempranillo, and the results, published to date, are collected in six scientific articles, focused on its effect on: (i) grape: Monastrell nitrogen composition [5] and Tempranillo phenolic composition [6]; (ii) wine: stilbenes content in Monastrell [4], volatile compounds in Monastrell [7] and a broad characterization of volatile, nitrogen and phenolic composition in Tempranillo [8]; and (iii) grape and wine: nitrogen composition in Monastrell [9].…”

“…Regarding the Tempranillo variety, the treatments in the vineyard with MeJ and ACP-MeJ improved the content of phenolic compounds in the grapes, the effect being dependent on the vintage, so that, in a vintage, MeJ increased the total content of anthocyanins and ACP-MeJ that of hydroxycinnamic acids (HCA); while, in the second vintage, the application of MeJ had no effect on the phenolic composition of the grapes and, however, ACP-MeJ increased the total content of flavonols, flavanols, gallic acid, and stilbenes [6]. Regarding the Tempranillo wine [8], its phenolic composition was little affected by the treatments with MeJ and ACP-MeJ carried out in the vineyard, since only the content of gallic acid and total HCA showed changes; furthermore, the total amino acids content was little affected; and volatile compounds decreased their concentration when applying both treatments in the first vintage, while in the second one, these compounds were not affected by ACP-MeJ, while esters and acids decreased again when applying MeJ, without effect on alcohols.…”

“…Nitrogen compounds are essential for the correct development of alcoholic fermentation [10,11]. Moreover, these compounds are precursors of the main fermentative volatile compounds [12,13], and have been especially affected by the applications in the Tempranillo vineyard of MeJ and ACP-MeJ [8], although the same effect was not observed when the treatments were applied in Monastrell [7], despite the important difference in the nitrogen composition of the grapes [9]. For all these reasons, the aim of this work was to study the influence of MeJ and ACP-MeJ foliar treatments on Tempranillo grape amino acids content over two vintages.…”