# From Vine to Wine: Coloured Phenolics as Fingerprints
## 4 Discussion
### Univariate Analysis
#### 4.1.1. Cultivar Analysis  
Significant variations in the anthocyanin profile across different grape cultivars were observed, supporting that genetic factors influence pigment biosynthesis [30]. As expected, M-3-glc is the most concentrated anthocyanin in all grape cultivars, as it is the most stable non-acylated anthocyanin [6]. Its higher concentration found in foreign cultivars such as R, C, and S supports the use of these international grapes for producing red wines with intense and stable red hues. Moreover, these higher M-3-glc concentrations compared to most of the autochthonous grape cultivars are likely due to clonal selection of cultivars commonly carried out in their regions of origin, which focused on enhancing red colour. Also, Acet concentrations were generally higher in foreign cultivars (S, R, and M) and also in the autochthonous T cultivar. Our results agree with previous studies [11] where the S cultivar also presented the highest percentage of acetylated anthocyanins. These anthocyanin derivatives are known for their higher colour stability compared to their non-acetylated counterparts, as they participate in intra-molecular copigmentation processes [16]. The higher levels of acetylated anthocyanins in T cultivar might suggest that this cultivar may be better suited for producing red wines due to its capacity for maintaining colour intensity over extended storage periods than the rest of Canary traditional cultivars. Interestingly the concentration of Cou showed a distinct pattern because the V cultivar had higher concentrations compared to foreign cultivars, with significant differences with respect to R cultivar. Despite its lower Tot concentration, the V cultivar had a higher mean Cou concentration, which might provide an advantage in the production of red wines, as Cou are usually associated with colour resistance to the oxidative degradation and, therefore, could retain the colour for a longer time.  
Concentrations of other minor glucosides such as D-3-glc and Pt-3-glc showed significant cultivar-specific differences. The foreign R and S cultivars, as well as the traditional C, exhibited higher concentrations, which could be due to an increased synthesis or higher colour stability in these cultivars. This could be related to a higher activity of flavonoid-3-hydrolase and flavonoid-3,5-hydrolase, which would produce different ratios between di- and trihydroxylated anthocyanins. C-3-glc presented no significant differences between cultivars and the lowest concentration, probably because it is the precursor of all the others [31]. Similarly, no significant differences between cultivars for Pe-3-glc were observed, as this anthocyanin is formed by the activity of the methyltransferase enzyme in C-3-glc [11]. The highest mean concentrations of Glc were observed in the traditional C and LN cultivars, as well as in the international R, with significant differences compared to V. This higher Glc concentration implies that these cultivars have a greater potential for producing young wines with a vivid and intense coloration. The variability in anthocyanin profiles across cultivars suggests that blending strategies could be employed to optimize wine colour and stability. For example, blending traditional cultivars rich in M-3-glc (C or LN) with those containing higher coumaryl derivatives (V) could produce wines with both immediate visual appeal and long-term colour stability.