**5. Conclusions**

DWF by BF or BFR at levels of 10, 20, 30 and 50% w/w on the total flour basis resulted in increased chelating capacity of breads. The highest Fe(II) chelating capacity was noted for BEDWBs with 50% substitution of DWF by BF or by BFR. This level of DWF substitution resulted in 40% increase in the chelating capacity of bread as compared to the reference DWB

The obtained results show that substitution of DWF by two types of buckwheat flour, especially by BF, enhanced the antioxidant properties of BEDWBs. This clear beneficial effect may be due to the enrichment of DWB in bioactive compounds, including rutin with well-recognized antioxidant properties. These results are consistent with the results obtained by Zielińska et al. [14] and Zieliński et al. [35]. Similarly, Lin et al. [21] showed that supplementation of wholegrain buckwheat flour in wheat bread resulted in increase of the antioxidant properties more than the application of light buckwheat flour. Whereas Yoo et al. [15] and Błaszczak et al. [16] found that rutin content in buckwheat groats is greatly reduced by thermal processing (by approximately 60%). This finding may explain the lower antioxidant capacity of buckwheat-enhanced dark wheat bread based on flour from roasted groats as compared to bread formulated with buckwheat flour as it was shown in this study. Many researchers also argue that phenolic compounds as well as compounds formed in Maillard reaction (e.g. HMF, furfural and acrylamide) play a significant role in scavenging of free radicals [36, 37]. However, the formation of Maillard reaction compounds can disguise actual reduction of phenolic contents and antioxidant capacity as well as loss of antioxidant activity in bread samples

Furthermore, the present study showed that BEDWBs were more effective scavengers of

differences were statistically significant (*p* < 0.05) (**Table 2**). An inverse relationship was found in the reference DWB. This trend in the rank of the radical scavenging activity was demonstrated by Floegel et al. [39] and Xu et al. [40]. Similarly, Sakač et al. [38] observed clear differences in antioxidant capacity between the light buckwheat enriched bread and whole-

One of the significant mechanisms to defend against oxidative damage and lipid peroxidation is to chelate metal ions. In this study, we observed significant differences in metal chelating activity and reducing power between the reference DWB and BEDWBs (**Table 3**). Especially, supplementation of BFR has contributed to an increased metal chelating activity of BEDWBs. Whereas, Sakač et al. [38] found significant differences in antioxidant capacity measured by metal chelating activity and reducing power between the light and wholegrain buckwheat enriched breads. Enhancement of the antioxidant activity of bread after application of buckwheat flour from milled roasted groats can be related to the modification and/or degradation of phenolic compounds and formation of Maillard reaction products such as melanoidins, which may also act as antioxidants [36, 37]. It is possible that the enhancement of bread

−•). These

radical cation (ABTS•+) than DPPH• radicals and superoxide anion radical (O2

(9.89 ± 0.01 µmol EDTA/g d.m.).

284 Superfood and Functional Food - An Overview of Their Processing and Utilization

throughout the heat treatment [38].

grain buckwheat enriched bread.

**4. Discussion**

This paper shows the beneficial role of the addition of buckwheat in bakery products. It highlights aspects of buckwheat as a food ingredient and possible use as flour in bakery products. The obtained results indicate that the improved antioxidant properties of buckwheat-enhanced dark wheat bread might be enhanced due to the incorporation of phenolic compounds, mainly rutin and quercetin, which had been shown to possess antioxidant activity. Overall, buckwheat breads could be developed as a source of antioxidant activity for humans.
