# Assessing the Performance of Different Grains in Gluten-Free Bread Applications
## 3 Results and Discussion
### Antioxidant Activity of the Breads
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Properties**} & \multicolumn{4}{c}{**Breads Prepared With**} \\ \cline{2-5}  & **Quinoa flour** & **Sorghum flour** & **Millet flour** & **Rice flour** \\ \hline Total phenol content, mg fertile acid & 398.42 \(\pm\) 0.15 & 387.16 \(\pm\) 0.11 & 180.09 \(\pm\) 0.10 & 70.34 \(\pm\) 0.10 \\ equiv/100 g d.w. & & & & \\ \hline DPPH-radical scavenging activity, \% & 32.85 \(\pm\) 0.11 & 35.01 \(\pm\) 0.10 & 19.24 \(\pm\) 0.10 & 10.50 \(\pm\) 0.11 \\ \hline FRAP, umoli Fe\({}^{2+}\)/g d.w. & 2.53 \(\pm\) 0.09 & 3.67 \(\pm\) 0.09 & 2.06 \(\pm\) 0.07 & 0.98 \(\pm\) 0.05 \\ \hline TEAC, umoli Trolox/g d.w. & 19.32 \(\pm\) 0.12 & 54.51 \(\pm\) 0.12 & 15.07 \(\pm\) 0.10 & 6.97 \(\pm\) 0.10 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Total phenol contents and antioxidant activity of quinoa, sorghum, millet and rice breads. [PERSON] et al. [14] reported for the free phenolic acids of red and white sorghum flours values of 81.19 and 150.67 \(\upmu\)g GAE/g d.w., respectively. [PERSON] et al. [17] found that the breads prepared from blends of wheat flour and 40% sorghum flour (red and white, respectively) had the free phenolic contents of 1.09-0.49 mg GAE/g d.w. Additionally, [PERSON] et al. [17] reported that the addition of red or white sorghum flour to the wheat flour increased the polyphenonic content and the antioxidant capacity of the bread. [PERSON] et al. [14] noted that the phenolic acids prevailing in the extract were ferulic acid, p-hydroxicbenzoic acid and salicylic acid. Besides these phenolic acids, the red sorghum flour contained flavonoids such as anthocyanins (luteolinidin and apigeninidin). Thermal processing of cereals usually causes the reduction of the flavonoid contents to different extents, depending on the food matrix and on the intensity of the thermal treatment [44]. In particular, [PERSON] et al. [14] noted that anthocyanins were less stable than phenolic acids during cooking. There are other phytochemicals, such as carotenoids, that contribute to the antioxidant activity of the samples [14]. [PERSON] et al. [47] studied the antioxidant activity of ten sorghum genotypes and reported variation of the FRAP, ABTS and DPPH values from 3.94 to 63.34, from 44.21 to 121.73 and from 1.83 to 65.73 \(\upmu\)mol Trolox/g, respectively, and of total phenol content values from 1.408 to 12.348 \(\upmu\)g catechchin equivalents/g. [PERSON] and [PERSON] [15] found higher free phenolic contents in finger millet (411-610 mg FAE/100 g), compared to the pearl and proso millets (168 mg FAE/100 g and 140 mg FAE/100 g, respectively). They registered different flavonoid contents of 203-228, 49 and 140 mg/100 g catechchin equivalent in the phenolic extracts obtained from finger, pearl and proso millet, respectively. [PERSON] and [PERSON] [48] showed that the main phenolic acids in millets are ferulic acid, gallic acid, p-hydroxicbenzoic acid, cumaric acid and proto-catechuic acid. [PERSON] et al. [49] found higher antioxidant activity (FRAP of 471.71 \(\upmu\)mol/g, DPPH-RSA and total phenol content of 1.73 and 373.15 mg Trolox/g, respectively) in finger millet compared to the rice (FRAP of 60.93-67.48 \(\upmu\)mol/g, DPPH-RSA and total phenol content of 0.49-1.23 and 47.64-56.61 mg Trolox/g, respectively). Previous studies mentioned a significant correlation between phenolics and antioxidant activity in quinoa [50]. Large variation of the total phenol content of quinoa seed from 28.49 to 1.59 mg gallic acid/100 g d.w. was reported by [PERSON] et al. [12]. Later study of [PERSON] et al. [13] revealed the phenolic profile of quinoa flour; the most abundant phenolic acids were 4-hydroxbenzoic, syringic acid, vanillic acid, gallic acid, ferulic acid and p-cumaric acid, while the most dominant flavonoids were neohesperidin, kaempferol and isoquercitin. In addition to the polyphenols and flavonoids which are know the possess antioxidant properties, [PERSON] et al.