## 3 Results and Discussion
### Effects of Waxy Barley Bran Blend Ratio
#### 3.3.2 Height and Specific Volume
The \(\beta\)-glucan content in these replacement groups ranged from 2.93 to 6.06 g, likely causing either dilution or underdevelopment of the gluten network due to water absorption by \(\beta\)-glucan, leading to differences in specific volume, height, and crumb. Protein, fatty acid, dietary fiber and ash content were also thought to influence crumb formation. Wheat flour gluten is gliadin/glutenin (about 50:50), whereas barley gluten is mainly hordein/glutelin (about 30:70), and this low hordein ratio is unfavorable for gluten network formation [39]. [PERSON] et al. (2025) [39] report that they experimented with samples with adjusted hordein/glutelin ratios of 25:75, 50:50 and 75:25. The results showed that an increase in hordein ratio (from 25:75 to 50:50) enhanced gluten-starch interactions by promoting gluten network matrix and continuous network formation. On the other hand, excessive hordein ratios (75:25) inhibited protein aggregation behavior and weakened the continuity and stability of the gluten network. The protein ratios of IBLP and OBLP used in this study were also considered to be close to a hordein/glutelin ratio of 30:70. Therefore, as the substitution ratio between IBLP and OBLP increased, the gluten network weakened, possibly affecting specific volume and height. Fathy acids are associated with changes in the secondary structure of gluten proteins. Namely, when the fatty acid content is high (especially when the content of unsaturated fatty acids is high), antiparallel \(\beta\)-Sheets were formed with hydrogen bonds between molecules [40]. IBLP and OBLP had unsaturated fatty acids, such as Linoleic acid and Alpha-linolenic acid fatty acid, at relatively high levels [9]. However, in the present study, bread height and specific volume decreased when the content of IBLP increased or when OBLP was added. The influence of \(\beta\)-glucan and protein was predominant in crumb formation, and the influence of fatty acids was smaller than other factors. The dietary fiber in hazelnut testa and ground flaxseed hulls also reduced the volume and overall acceptability [41; 42]. Similar to \(\beta\)-glucan, replacing wheat flour with a certain amount of fiber may have disrupted the gluten-starch matrix and limited gas cells [43]. This disruption of the gluten matrix was thought to be due to competition between dietary fiber and the gluten proteins for water, resulting in aggregation of the gluten proteins. The water molecules of the dough interact with the dietary fiber rather than with the polypeptide chains of the protein, resulting in partial dehydration of the gluten matrix. It was thought that the aggregation was thereby caused by the interaction of the polypeptide chains or the interaction of the polypeptide chains with the polysaccharide chains [44; 45; 46]. With regard to minerals, the formation of gluten networks is weaker at low sodium chloride concentrations [47]. However, it has been reported that the addition of sea salt containing iron, zinc and magnesium does not affect the rheology and volume of the dough [48; 49]. In the present study, the effect of ash (wheat flour 0.4 g/100 g, IBLP 2.6 g/100 g and OBLP 4.1 g/100 g) in the samples on the formation of gluten was considered small because of the addition of sodium chloride. Collectively, these findings suggest that IBLP at 10% can serve as the optimal proportion for improving specific volumes of bread.