# Usefulness of Rowanberry for Improving the Nutritional Value of Buckwheat Flour Extrudates
## 3 Results and Discussion
### DPPH, CUPRAC, and FRAP Antioxidant Activities  
The DPPH, CUPRAC, and FRAP of the extruded samples prepared with corn-buckwheat in different percentages are seen in Table 3. Increasing the buckwheat content of the control and milk-containing samples increased the antioxidant activity. The highest DPPH, CUPRAC, and FRAP were determined as 2.43 mg TE/g, 7.28 mg TE/g, and 1.14 mg TE/g in control samples with 50% buckwheat added, respectively. Buckwheat was reported as a good source of antioxidant compounds. [PERSON] et al. (2018) reported that the DPPH antioxidant capacity of extruded products produced using corn flour and buckwheat flour in different ratios (70:30, 50:50, and 30:70) increased with the increase in the buckwheat content. [PERSON] et al. (2017) investigated the properties of corn grit extrudates containing buckwheat flour at different rates (0, 10, 20, and 30 \(w\)/\(w\)). They determined the antioxidant activity of extruded products to be between 1.07 and 1.25 uM TE/mg. They also reported a similar trend in antioxidant activity. The increase in the antioxidant activity of the samples may also be associated with the Maillard reaction. Some Maillard reaction products were reported to have high antioxidant activity ([PERSON] et al., 2018). Figure 8: Box-whisker plots of the total flavonoid content values of extrudate samples. Mean \(\pm\) 1.96*standard deviation (SD) of the mean describes a 95% confidence interval. **30W**: 30% Buckwheat + 30% Corn grits + Water; **40W**: 40% Buckwheat + 40% Corn grits + Water; **50W**: 50% Buckwheat + 50% Corn grits + Water; **30M**: 30% Buckwheat + 30% Corn grits + Milk; **40M**: 40% Buckwheat + 40% Corn grits + Milk; **50M**: 50% Buckwheat + 50% Corn grits + Milk; **30 WR**: 30% Buckwheat + 30% Corn grits + Water + Rowanberry; **40 WR**: 40% Buckwheat + 40% Corn grits + Water + Rowanberry; **50 WR**: 50% Buckwheat + 50% Corn grits + Water + Rowanberry; **30 MR**: 30% Buckwheat + 30% Corn grits + Milk + Rowanberry; **40 MR**: 40% Buckwheat + 40% Corn grits + Milk + Rowanberry; **50 MR**: 50% Buckwheat + 50% Corn grits + Milk + Rowanberry. The DPPH, CUPRAC, and FRAP of rowanberry-added extruded samples prepared with buckwheat in different percentages are seen in Table 3. The supplementation of rowanberry to the control samples showed the highest antioxidant activity in the 40% buckwheat sample. The DPPH, CUPRAC, and FRAP values of this sample increased by 55%, 30%, and 75% compared to the control sample, respectively. Among the samples containing rowanberry and milk, the 30% buckwheat sample showed the highest DPPH activity, while the 40% buckwheat sample demonstrated the highest CUPRAC and FRAP. According to previous studies, rowanberry fruit is rich in antioxidant compounds [62, 66]. In a previous study, the DPPH antioxidant capacity of rowanberry extracts was determined as 73 umol TE/g, 103 umol TE/g, and 309 umol TE/g in acetone, ethanol, and water solvents, respectively. For FRAP, it was determined as 117 umol TE/g, 118 umol TE/g, and 323 umol TE/g [62]. Therefore, this additive in extrudates caused a significant increase in the antioxidant activity of the sample. In addition, it has been reported that antioxidant and antiradical activities in extruded products depend not only on the ratio of bioactive compounds but also on the composition of these compounds [1]. The antioxidant activity of corn and buckwheat extrudates with rowanberry has not been reported in the literature, but the extrudates containing different fruits have been reported. [PERSON] et al. [40] determined that the rowanberry pomace added to the shortbreach cookies at 20% showed remarkably higher DPPH antioxidant activity in the product. [PERSON] et al. [41] determined that blueberry, grape, cranberry, and raspberry powders added to breakfast cereals increased the antioxidant activity of the product. Similarly, [PERSON] et al. [21] observed an increase in the antioxidant activity of corn extrudates added with rosehip pomace powder compared to those without additives. In another study, [PERSON] et al.