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

摘要

Aims: To determine the anthocyanin composition in Carignan and Grenache grapes and wines as affected by vintage, plant vigor and bunch uniformity.Methods and results: 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.Conclusion: 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.Significance and impact of the study: 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. IntroductionGrapes of red varieties contain large amounts of anthocyanin compounds in the skins, and sometimes in the pulp too. These anthocyanins are partially extracted during winemaking. For the European Vitis vinifera species, there are five monoglucoside anthocyanins and their corresponding acylate derivatives (acetyl and p-coumaryl); malvidin-3-O-glucoside is the most abundant anthocyanin (Pomar et al. 2005), although in some varieties peonidin-3-O-glucoside predominates (Mattivi et al. 2006). The evolution of anthocyanins during veraison and ripening corresponds to different enzymatic activities at the cellular level (Castellarín et al. 2011). In He et al. (2010)’s review, two synthetic pathways were described from naringenin flavanone: one that generates anthocyanidin cyanidin from the action of F3'H (flavonoid 3'-hydroxylase), DFR (dihydroflavonol 4-reductase) and ANS (anthocyanidin syntase) and another that generates anthocyanidin delphinidin from the action of F3'5'H (flavonoid 3', 5'-hydroxylase), DFR and ANS. The action of UFGT (UDP glucose:flavonoid-3-O-glucosyltransferase) generates cyanidin-3-O-glucoside from cyanidin and, finally, peonidin-3-O-glucoside by the action of OMT (O-methyltransferase). UFGT also synthesizes delphinidin-3-O-glucoside from delphinidin and the action of OMT generates petunidin-3-O-glucoside and malvidin-3-O-glucoside. At the end of the ripening process, the synthesis and accumulation of the non-acylated anthocyanins is slowed down or even stopped whereas there is some increase with the acylated derivatives (p-coumarylated and/or acetylated) (González-San José and Díez 1992, Jordao et al. 1998, Ryan and Revilla 2003).Anthocyanin composition depends on the interaction between climate, soil, viticultural practices and genotype (Jackson and Lombard 1993, Downey et al. 2006), which involves variations in the expression of genes coding for different enzymes (Yamane et al. 2006). Canopy management modifies the growth and structure of the vine, causing changes in exposure to solar radiation and temperature in the fruit zone (Smart 1985, Smart 1987, Bergqvist et al. 2001). Dense canopies increase the level of shading in the fruit zone, causing a reduction in the activity of F3'5'H or an increase in the activity of F3'H and hence an increase in the concentration of dioxygenated anthocyanins: peonidin-3-O-glucoside and cyanidin-3-O-glucoside (Downey et al. 2004). Some authors, however, found quite the opposite result in colder weather conditions, such as in northern Italy (Chorti et al. 2010) and north-eastern United States (Tarara et al. 2008). Temperature is also a factor that alters the biosynthetic pathway of dioxygenated or trioxygenated (malvidin-3-O-glucoside, petunidin-3-O-glucoside, and delphinidin-3-O-glucoside) anthocyanins. According to Cohen et al. (2008), the proportion of dioxygenated anthocyanins should increase under conditions of low daytime temperatures. Conversely, Guidoni et al. (2008) referred to the sensitivity of the enzyme F3'H to temperature in order to justify the high concentrations of dioxygenated anthocyanins found in Nebbiolo grapes during a warm year as opposed to a cool year.The distribution of anthocyanins between the acylated and non-acylated forms is altered by the combination of temperature and solar radiation. This is because acyltransferase activity increases with temperature (Haselgrove et al. 2000, Spayd et al. 2002). This combination is complex because it can be synergistic if the te