## 3 Results and Discussion
### Texture Profile Analysis (TPA) of Bread
For instance, fine wheat bran has been shown to increase hardness more significantly than coarser fractions [45], while some hydrocolloids such as almond gum can soften bread when used at optimal concentrations [46]. Similarly, [PERSON] et al. [7] found that breads containing up to 15% fermented oat beverage by-products exhibited reduced crumb firmness after 96 h, supporting the notion that fiber-rich oat materials can positively influence bread softness during storage. Springiness, which measures the ability of the crumb to recover after compression, decreased in all samples over time. The control bread retained the highest springiness at both 24 and 72 h (0.86), while the most substantial decrease (\(p\leq 0.05\)) was observed in BO100 (to 0.52). Similar significant (\(p\leq 0.05\)) reductions were noted in BS100 and BM100 (0.58 and 0.61, respectively), indicating gradual weakening of the crumb structure, particularly in high-fiber formulations. According to [PERSON] et al. [47] and [PERSON] et al. [10], decreased aeration and increased dough density are associated with reduced crumb springiness. This supports the trend observed in the current study, especially for oat-based breads at high substitution levels. A strong negative correlation (at 24 h) was observed between substitution level and springiness, particularly in BO (r = \(-\)0.96), BM In Proceedings of the (r = \(-\)0.99), and BS In Proceedings of the (r = \(-\)0.91), confirming the dose-dependent weakening of elastic recovery. Cohesiveness, which reflects internal structural bonding, also declined during storage. Initially, the control sample had the highest cohesiveness (0.62), while BO100 and BS100 exhibited the significantly (\(p\leq 0.05\)) lowest values (0.38 and 0.44, respectively). By 72 h, all variants showed further decreases, particularly at high substitution levels. These results suggest that high proportions of cereal-based beverages, particularly those rich in fiber and fat, may interfere with the gluten matrix, reducing structural integrity during prolonged storage. Although these structural changes were inferred from texture and farinographic data, it should be noted that no direct microscopic observations or gluten index measurements were conducted in this study. As reported by [PERSON] et al. [10], high-fiber residues interfere with gluten continuity, reducing elasticity and cohesiveness--a phenomenon also evident in our study. [PERSON] et al. [7] similarly noted that breads enriched with fermented oat by-products maintained acceptable cohesiveness over four days of storage, especially at moderate (15%) inclusion levels. These effects are likely related to the physicochemical interactions between soluble dietary fibers and the gluten network. Fibers such as \(\beta\)-glucans can compete with gluten proteins for water, thereby limiting protein hydration and network formation. In addition, they may sterically hinder protein-protein bonding and act as structural diluents, weakening the continuity and elasticity of the gluten matrix [24; 25; 38]. Such mechanisms help explain the pronounced decrease in cohesiveness observed in BO100 and BS100, where fiber content is highest. The strength of this effect is supported by the high negative correlations (at 24 h) between beverage level and cohesiveness, reaching r = \(-\)0.97 for both BO and BS, and In Proceedings of the r = \(-\)0.99 for BM. Cheviness, a compound parameter derived from hardness, springiness, and cohesiveness, mirrored the trends in those variables. At 24 h, the highest chewiness values were recorded in the control (5.2 N) and BM25 (4.3 N). Chewiness also showed a strong negative correlation with substitution level across all beverages (r = \(-\)0.93 for BO, \(-\)0.89 for BS, and \(-\)0.95 for BM), indicating that higher inclusion levels consistently reduced textural resistance. At 72 h, chewiness increased slightly in most samples but remained significantly lower (\(p\leq 0.05\)) in BO100 and BS100 (1.6-3.0 N), suggesting improved resistance to staling.