## 3 Results and Discussion  
### In Silico Analysis of Conformational Effects on Mx3 glc Predicted Color  
The visible absorbance spectra for the different mv3 glc conformers computed by the time-dependent density functional theory (in the positively charged flavylium state) with the dispersion-corrected hybrid functional B3 LYP are shown in Figure 2, while their corresponding simulated CIELAB color parameters (\(L^{*}\), \(a^{*}\), \(b^{*}\), \(C^{*}_{ab}\), and \(h_{ab}\)) are presented in Table 1.  
Mv3 glc conformers differ from each other in the torsion of the dihedral angle \(\theta\), which was modified from 0\({}^{\circ}\) to 90\({}^{\circ}\) to cover a wide range of conformations. Considering the planar geometry of the flavylium chromophore (\(\theta\) = 0\({}^{\circ}\)), the computed spectra for mv3 glc in the visible range included a single strong absorption peak between 470 and 530 nm (\(\lambda_{\max}\) = 498 nm; Figure 2), which corresponds in qualitative terms to the spectrum characteristics obtained for malvin by [PERSON] et al. [33], who used the B3 PYL XC functional, and for mv3 glc by [PERSON] et al. [34] based on the IEFPCM-B3P86/6-311+G(d,p) theoretical level. In this study, a deviation from planarity in the calculations between 0\({}^{\circ}\) and 60\({}^{\circ}\) does not affect the global shape or the number of simulated spectral peaks of mv3 glc conformers but reflects important variations in the position of the main absorption band peak and its intensity. The theoretical results reproduced a progressive bathochromic effect in the mv3 glc computed spectra by 58 nm at increasing molecular torsions from 0\({}^{\circ}\) to 60\({}^{\circ}\) (\(\lambda_{\text{max}}\) = 498 nm and 556 nm, respectively) simultaneously with a notably hypochromic effect. A greater deviation from planarity (\(\theta\) torsion larger than 60\({}^{\circ}\)) reproduces a suppression of the absorption in the visible range of the flavylium chromophore. Previous computational studies with cyanidin-3-glucoside have shown that changing the dihedral angle significantly affects its optical behavior, depending on several competing effects such as the orientation of the hydroxyl groups in the aglycone structure or the relative position of the sugar in the 3\({}^{\prime}\) position [26; 35]. By applying the tristimulus colorimetry algorithms to the computed spectra, the _in silico_ methodology allowed the prediction of the color of the different mv3 glc conformers, both in quantitative (\(L^{*}\) and \(C^{*}_{ab}\)) and qualitative (\(h_{ab}\)) colorimetric terms (Table 1). Considering no torsion effect in the mv3 glc structure (\(\theta\) = 0\({}^{\circ}\)), the computed CIELAB parameters were \(L^{*}\) = 50.27, \(C^{*}_{ab}\) = 50.41, and \(h_{ab}\) = 1.47\({}^{\circ}\), which would correspond to a vivid red hue. These results predicted by computational tools match the color exhibited by mv3 glc in its flavylium cation form in solutions observed in previous experimental studies [16]. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Mv3 glc** & **Dihedral** & \(L^{*}\) & \(a*\) & \(b*\) & \(C^{*}_{ab}\) & \(h_{ab}\) \\
**Conformation** & **Angle (\(\theta\))** & & & & & \\ \hline
1 & 0 & 50.27 & 50.39 & 1.30 & 50.41 & 1.47\({}^{\circ}\) \\
2 & 10 & 50.24 & 50.73 & \(-\)2.72 & 50.80 & 356.94\({}^{\circ}\) \\
3 & 20 & 49.71 & 50.33 & \(-\)4.73 & 50.55 & 354.63\({}^{\circ}\) \\
4 & 30 & 49.68 & 50.11 & \(-\)12.92 & 51.75 & 345.54\({}^{\circ}\) \\
5 & 40 & 50.83 & 48.33 & \(-\)25.89 & 54.83 & 331.82\({}^{\circ}\) \\
6 & 50 & 55.92 & 39.87 & \(-\)37.68 & 54.86 & 316.61\({}^{\circ}\) \\
7 & 60 & 67.90 & 20.21 & \(-\)35.49 & 40.84 & 299.66\({}^{\circ}\) \\
8 & 70 & 89.80 & 1.68 & \(-\)9.91 & 10.05 & 279.63\({}^{\circ}\) \\
9 & 80 & 93.61 & 2.08 & \(-\)4.85 & 5.28 & 293.77\({}^{\circ}\) \\
10 & 90 & 97.61 & 2.67 & 0.48 & 2.71 & 10.23\({}^{\circ}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: In silico color parameters of the mv3 glc conformations at increasing torsions of the dihedral angle.