Anthocyanin composition in Carignan and Grenache grapes and wines as affected by plant vigor and bunch uniformity

Abstract

<p style="text-align: justify;"><strong>Aims</strong>: To determine the anthocyanin composition in Carignan and Grenache grapes and wines as affected by vintage, plant vigor and bunch uniformity.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Anthocyanin composition of Carignan and Grenache grapes and wines were analysed by chromatographic techniques considering the influence of two different vigor levels over two vintages. The heterogeneity in the distal parts of the bunch was also taken into account. Warm vintage was better for the accumulation of anthocyanins. However, each variety responsed differently according to vine vigor. Grenache anthocyanin synthesis decreased in low vigor (weak) vines, whereas Carignan anthocyanin content depended on vigor, berry size, rootstock and vintage. In both varieties, but more significantly in Carignan, there was a tendency to accumulate acylated anthocyanins in bottom berries.</p><p style="text-align: justify;"><strong>Conclusion</strong>: Carignan anthocyanin concentration was increased in low vigor plants, where clusters received greater sun exposure, unlike Grenache, where better canopy management in the fruit zone is necessary. Avoiding the poor growing conditions for Grenache in the region and improving the canopy/fruit ratio deserves careful consideration in order to reach optimal anthocyanin content.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: Knowledge of anthocyanin accumulation according to both plant vigor and bunch ripeness is of major importance to determine the optimal harvest date for each cultivar and thus improve the quality of wine.</p>