## 3 Results and Discussion
### Effects of Waxy Barley Bran Blend Ratio
#### 3.3.3 \(\beta\)-Glucan, TPC, and Antioxidant Activity  
The results for \(\beta\)-glucan, TPC, and antioxidant properties are shown in Figure 5. The control group had the lowest \(\beta\)-glucan content at 0.14 g/100 g DW. The IBLP (10%, 30%, and 50%) replacement groups had \(\beta\)-glucan contents of 0.50, 1.25, and 1.94 g/100 g DW, respectively. This finding indicated a significant (\(p<0.05\)) increase in \(\beta\)-glucan content with increased IBLP replacement. The 30% OBLP replacement group showed a \(\beta\)-glucan content of 0.67 g/100 g DW. The TPC content differed significantly (\(p<0.05\)) among the groups, with the 30% OBLP replacement group exhibiting the highest TPC (149.85 mg CTN eq/g DW), followed by 50% IBLP replacement (124.82 mg CTN eq/g DW), 30% IBLP replacement (109.03 mg CTN eq/g DW), 10% IBLP replacement (87.64 mg CTN eq/g DW) and control (76.35 mg CTN eq/g DW) groups, respectively. Figure 5: Effect of different mixing proportions of waxy barley bran on \(\beta\)-glucan content (**a**), TPC (**b**), DPPH (**c**), H-ORAC (**d**), and ABTS (**e**). Bars represent the mean \(\pm\) standard error (\(n=8\) for \(\beta\)-glucan, \(n=6\) for TPC, DPPH, and ABTS, \(n=4\) for H-ORAC). Different letters (a–e) indicate significant differences (\(p<0.05\)). IBLP—inner bran layer powder; OBLP—outer bran layer powder; TPC—total polyphenol content; CTN eq—catechin equivalent; TE—Trolox equivalent; DW—dry weight. The antioxidant activities assessed using the DPPH assay revealed significant differences (\(p<0.05\)) among the groups and a similar pattern of changes between the groups as observed for TPC. Namely, the 30% OBLP replacement group showed the highest antioxidant activity (1.23 \(\upmu\)mol TE/g DW), followed by the 50%, 30%, 10% IBLP replacement, and control groups (0.91, 0.78, 0.48, and 0.28 \(\upmu\)mol TE/g DW, respectively). H-ORAC assay also revealed similar results with the following increasing order: control group, 8.41 \(\upmu\)mol TE/g DW; 10% IBLP replacement group, 9.37 \(\upmu\)mol TE/g DW; 30% IBLP replacement group, 12.37 \(\upmu\)mol TE/g DW; 50% IBLP replacement group, 14.02 \(\upmu\)mol TE/g DW; 30% OBLP replacement group, 18.27 \(\upmu\)mol TE/g DW. No significant differences were found between the control and 10% IBLP replacement group, or between the 30% IBLP replacement group and the 50% replacement group, but the 30% OBLP replacement group showed significantly higher values (\(p<0.05\)). The ABTS radical scavenging activity was the lowest (\(p<0.05\)) for the control group (1.11 \(\upmu\)mol TE/g DW), which increased with increasing proportions of IBLP (1.34, 1.67, and 1.78 \(\upmu\)mol TE/g DW, in 10%, 30%, and 50% IBLP replacement groups, respectively), with the highest ABTS value being observed in the 30% OBLP replacement group (2.33 \(\upmu\)mol TE/g DW). In summary, the \(\beta\)-glucan contents, TPC, DPPH, H-ORAC, and ABTS values in the IBLP and OBLP replacement groups were 3.62-13.93, 1.15-1.96, 1.74-4.42, 1.11-2.17, and 1.20-2.09 times higher than those in the control group. \(\beta\)-glucan is abundant in the endosperm of barley [50]. IBLP, which is closer to the endosperm, contained more \(\beta\)-glucan (6.13 g/100 g DW) than OBLP (4.85 g/100 g DW) [9]. Therefore, the increased \(\beta\)-glucan content in IBLP replacement groups compared to OBLP replacement group, even at the same substitution rate, could be attributed to the high \(\beta\)-glucan content of IBLP. The European Food Safety Authority (EFSA) recommends a daily intake of 3 g of \(\beta\)-glucan for maintaining normal blood cholesterol levels [51]. Based on the \(\beta\)-glucan content of IBLP and OBLP, the \(\beta\)-glucan content per serving (70 g) of bread was calculated to be 0.22, 0.64, 1.03, and 0.60 g for the bread with 10%, 30%, and 50% IBLP and 30% OBLP replacement groups, respectively. These amounts contribute 7.4-34.3% of the daily intake requirement, indicating their potential as useful \(\beta\)-glucan sources.