# Assessing the Performance of Different Grains in Gluten-Free Bread Applications
## 3 Results and Discussion
### Antioxidant Activity of the Breads  
The total phenol contents and antioxidant activity of quinoa, sorghum, millet and rice breads are reported in Table 4. The total phenol content of the breads varied from 70.34 to 398.42 mg FAE/100 g d.w. The highest total phenol content was registered in case of bread prepared with quinoa flour, while the lowest content was obtained for bread prepared with rice flour. The antioxidant properties of breads were evaluated by measuring the DPPH-radical scavenging activity, and by TEAC and ABTS and FRAP methods. [PERSON] et al. [43] mentioned that the TEAC method quantifies both lipophilic and hydrophilic antioxidants, comprising carotenoids, hydroxycinnamates, and flavonoids, while the DPPH-radical scavenging activity is mainly due to the phenolic compounds [25]. In order to directly measure the antioxidants or reductants in samples the FRAP assay was used. All methods applied for assessing the antioxidant properties indicated that the antioxidant ability of the bread samples decreased in the following order: sorghum \(>\) quinoa \(>\) millet \(>\) rice (Table 4). Sorghum and quinoa breads had higher value of FRAP, indicating the presence of Fe\({}^{2+}\) chelating agents in these samples. The results reported in the literature for the antioxidant activity of different types of flours and breads are very different due to many factors related both to the investigated samples, such as the genotype of the grains and environmental conditions, and to the techniques used for preparing the extracts and quantification of the antioxidant activity [13]. Therefore, is rather difficult to compare our results with those of other authors. [PERSON] et al. [3] studied the antioxidant properties of bread prepared with blends of wheat flour and quinoa flour and found that the phenolic content, ABTS and DPPH-RSA increased with increase of the levels of quinoa flours. They reported a loss of total polyphenol after baking. Similarly, when testing the possibility of using amaranth, quinoa, buckwheat and wheat for obtaining nutritionally enhanced gluten-free formulations, [PERSON] et al. [44] reported the overall decrease of the antioxidant activity and total phenol content following bread making. Anyway, new substance with antioxidant properties can be synthesized during baking, such as Maillard reaction products, which can be mainly found in the bread crust. [PERSON] et al. [45] observed the increase of the antioxidant activity of cookies during baking process with increasing the sugar level, temperature and time, most probably due to the formation of melanoidins. The antioxidant activity of cookies was stable after baking at 180 \({}^{\circ}\)C suggesting the completion of the reactions resulting in molecules with radical scavenging ability. Furthermore, the phenolics breakdown or other degradation reactions might result in products responsible for the increase antioxidant activity. [PERSON] and [PERSON] [46] reported the increase of the antioxidant activity up to five times with the increase of baking temperature and time. They explained this increase by the formation of the antioxidant compound pronyl-L-lysine. Moreover, they found higher antioxidant activity in crust in comparison to the crumb and untreated flour.