## 3 Results and Discussion
### Thermogravimetric Analysis (TGA)
Its negative orientation suggests that all QUE added to the model dough may be incorporated into the glutenin polymeric network. The fact that the glutenin-QUE thermograms are the least structured, i.e., we observe only three peaks, may be related to the unbranched structure of QUE (i.e., all aromatic rings and functional groups lie in the same plane). Therefore, the QUE molecule can incorporate into the glutenin network and stabilize it. In the case of other flavonoids and glycosides, whose structure is more branched (i.e., some functional groups and/or aromatic rings lie out of plane), the thermal behavior is less ordered compared to the glutenin-QUE  
Figure 1: Difference TGA thermograms calculated by subtraction of the gliadin thermogram from thermogram of gliadin–polyphenol: (**a**) quercetin (QUE), (**b**) rutin (RUTG), (**c**) naringin (NAR), (**d**) naringenin (NARG), (**e**) hesperitin (HET), and (**f**) hesperidin (HEDG). complex. However, a comparison of the difference thermogram shows similarities in thermal behavior between RUTG and NARG and NAR and HEDG. Similar results were obtained for gliadins. The thermograms of glutenin-RUTG/NARG 0.05 and 0.1 samples show a negative peak at ca. 300 \({}^{\circ}\)C, whose intensity increases with increasing RUTG concentration. This increase suggests the incorporation of both glycosides into the glutenin network. In contrast, the difference thermograms of glutenin-RUTG/NARG 0.2 samples are similar to the difference thermograms of glutenin-QUE samples. This similarity may indicate that some glutenin polypeptide chains interact with QUE, RUTG, and NARG in the same way as gliadins. However, these results do not enable the determination of the place of chemical bond formation. An analysis of the difference thermograms for glutenin-NAR 0.1 and all glutenin-HEDG samples also suggests a similar method of interaction, but there is too little information to determine the place of the interaction. Figure 2: Difference TGA thermograms calculated by subtraction of the glutenin thermogram from thermogram of glutenin–polyphenol: (**a**) quercetin (QUE), (**b**) rutin (RUTG), (**c**) margin (NAR), (**d**) naringenin (NARG), (**e**) beseritin (HET), and (**f**) hesperidin (HEDG). These studies show that the addition of flavonoids and their glycosides to gluten proteins affects their thermal properties, which may affect the quality of bread. TGA and DSC analyses have shown that flavonoids such as quercetin, naringenin, hesperetin, and their glycosides (rutin, naringin, and hesperidin) caused changes in the secondary and tertiary structure of gluten, modifying disulfide bridges and the amino acid environment, as well as influencing the thermal stability of the gluten network [10]. During baking, flavonoids mainly interact with gluten proteins through hydrogen and hydrophobic bonds, leading to changes in the protein structure, which may affect the texture, volume, and sensory properties of bread [22]. The incorporation of polyphenols into the gluten network may have a beneficial effect on the nutritional quality of the final product, improving its health and functional properties. Although it is known that polyphenols are thermally degraded under the influence of high temperature, which reduces their bioactivity [23], they can remain thermally stable in the gluten network after binding to gluten proteins. Such an interaction may protect polyphenols from degradation. It has been confirmed that flavonoids retain their biological activity after baking, and their bioavailability is high, which translates into an increase in antioxidant activity in the blood after the consumption of such bread [24].