## 3 Results and Discussion
### Differential Scanning Calorimetry (DSC)  
The DSC parameters (denaturation peak temperature (T) and transition enthalpy (\(\Delta\)H)) and DSC thermograms of both gluten proteins are presented in Table 2 and Figures S4 and S5 in the Supplementary Material, respectively. The DSC thermograms showed two negative peaks at 76 and 308 \({}^{\circ}\)C for gliations (see Figure S4), and one negative and one positive peak at 91 and 302 \({}^{\circ}\)C, respectively, for glutenins (see Figure S5). The first peak for both kinds of proteins is exothermic (\(\Delta\)H \(\cong\) 180 J g\({}^{-1}\)) and connected with water evaporation. The second peak is connected with protein decomposition [25]. In the case of gliadins, this peak is exothermic, with a transition enthalpy of 263 J g\({}^{-1}\), whereas glutenins show an endothermic peak, and the enthalpy value is ca. 29 J g\({}^{-1}\). In the case of gluten, which consists of gliadins and glutenins, the authors of [9] observed an exothermic peak connected with gluten decomposition at ca. 305 \({}^{\circ}\)C.  
\begin{table}
\begin{tabular}{l l l l l l l l l l} \hline \hline
**Polyphenyl** & **T\({}_{1}\) (\({}^{\circ}\)C)** & **\(\Delta\)H\({}_{1}\) (\({}^{\circ}\)g\({}^{-1}\))** & **T\({}_{2}\) (\({}^{\circ}\)C)** & **\(\Delta\)H\({}_{2}\)** & **T\({}_{3}\) (\({}^{\circ}\)C)** & **\(\Delta\)H\({}_{3}\)** & **T\({}_{4}\) (\({}^{\circ}\)C)** & **\(\Delta\)H\({}_{5}\) (\({}^{\circ}\)C)** & **\(\Delta\)H\({}_{6}\) (J g\({}^{-1}\))** \\ \hline glia\_control & 76 (2) \({}^{\text{bcd}}\) & \(-\)179 (2) \({}^{\text{f}}\) & & & & 308 (2) \({}^{\text{f}}\) & \(-\)263 (2) \({}^{\text{e}}\) & & \\ glia\_QUE & 80 (2) \({}^{\text{dof}}\) & \(-\)180 (2) \({}^{\text{ef}}\) & & & 267 (3) \({}^{\text{b}}\) & 136 (2) \({}^{\text{g}}\) & 324 (1) \({}^{\text{f}}\) & 44 (2) \({}^{\text{f}}\) & & \\  & 81 (1) \({}^{\text{f}}\) & \(-\)196 (2) \({}^{\text{c}}\) & & & 262 (2) \({}^{\text{b}}\) & 89 (1) \({}^{\text{f}}\) & 320 (2) \({}^{\text{f}}\) & 60 (1) \({}^{\text{m}}\) & & \\  & 76 (2) \({}^{\text{bcd}}\) & \(-\)190 (3) \({}^{\text{d}}\) & & & 249 (3) \({}^{\text{e}}\) & 41 (2) \({}^{\text{e}}\) & 308 (1) \({}^{\text{f}}\) & 55 (2) \({}^{\text{f}}\) & & \\  & 105 (2) \({}^{\text{g}}\) & \(-\)21 (2) \({}^{\text{l}}\) & & & & 322 (2) \({}^{\text{l}}\) & \({}^{\text{l}}\) & 154 (2) \({}^{\text{l}}\) \({}^{\text{l}}\) \({}^{\text{l}}\) \({}^{\text{l}}\) \({}^{\text{l}}\) \({}^{\text{l}}\) \({}^{\text{l}}\) \({}^{\text{gThe DSC thermograms of all modified protein samples also show an exothermic peak related to the water evaporation in the temperature range of 70-100 \({}^{\circ}\)C (peak T\({}_{1}\)). In the case of gliadin samples, this temperature is ca. 15 \({}^{\circ}\)C lower compared to glutenin samples (see Table 2). This difference can be attributed to the molecular weight of the studied proteins, since gliadins are monomeric proteins with a low molecular weight (30-80 kDa), whereas glutenins are polymeric and characterized by a high molecular weight (500-10,000 kDa) [17]. Polymeric proteins contain more water molecules that are bound inside the protein complex, and therefore, more energy is needed to release them. This peak is not observed in the DSC thermograms of pure flavonoids and their glycosides. The unmodified gliadin decomposition is observed at 308 \({}^{\circ}\)C as an exothermic peak. The addition of the QUE shifts this peak toward higher temperatures to ca. 320 \({}^{\circ}\)C. An increase in the QUE concentration to 0.2% causes the decomposition temperature to be similar to that recorded for the gliadin control sample. Additionally, the presence of the QUE changes the character of the thermal transition to endothermic, and its enthalpy decreases by about five times. The peak at 320 \({}^{\circ}\)C could be assigned to free QUE decomposition since the thermogram of the free QUE has a sharp, intensive peak at this temperature (see Figure S4a). However, the QUE decomposition is exothermic, while the decomposition of gliadin-QUE samples is endothermic.