Study of the evolution of nitrogen compounds during grape ripening. application to differentiate grape varieties and cultivated systems.
The aim of this work was to study the evolution of amino acids and ammonium during grape ripening and to evaluate its application to differentiate grape varieties and cultivated systems (organic and nonorganic). For this purpose, Monastrell, Syrah, Merlot, and Petit Verdot grapes produced using conventional agriculture and Monastrell grape cultivated using organic agriculture, collected during two consecutive harvests at different stages of ripening, were studied. These years of harvest were very different climatic years; even so, the grape varieties presented similar qualitative compositions. Therefore, the percentage of amino acids at harvest moment allowed differentiation of grapes according to variety and cultivated system, regardless of the year. The nitrogen composition could allow estimation of the fermentative aroma potential of grapes. Thus, Syrah was the grape with the greatest aroma potential at harvest. Monastrell nonorganic grape had a concentration of nitrogen compounds superior to that of Monastrell organic grape. In Monastrell, Syrah, and Merlot, traditional varieties in the area, the highest concentration of nitrogen compounds coincided with the highest degrees Baume/total acidity ratio and color index during 2007. Consequently, technological and phenolic maturity of these grape varieties coincided with the maximum composition of nitrogen compounds. However, in 2008, this did not happen because grape ripening was irregular as a consequence of different climatological conditions.
Garde-Cerdán
Teresa
T
Catedra de Quimica Agricola, ETSI Agronomos, Universidad de Castilla-La Mancha, Campus Universitario, Albacete, Spain.
Lorenzo
Cándida
C
Lara
José Félix
JF
Pardo
Francisco
F
Ancín-Azpilicueta
Carmen
C
Salinas
M Rosario
MR
D000383:Agriculture / Q000379:methods; D000596:Amino Acids / Q000032:analysis; D002980:Climate; D058870:Food, Organic; D005638:Fruit / Q000737:chemistry* / Q000254:growth & development*; D017672:Nitrogen Compounds / Q000032:analysis*; D000644:Quaternary Ammonium Compounds / Q000032:analysis; D012621:Seasons; D013045:Species Specificity; D027843:Vitis / Q000254:growth & development*; D014920:Wine / Q000032:analysis
D000596:Amino Acids; D017672:Nitrogen Compounds; D000644:Quaternary Ammonium Compounds