## 3 Results and Discussion
### Shelf-Life of Wheat Breads Fortified with SWAP  
#### 3.2.1 Changes in Bread Texture  
The staling process of control and SWAP-enriched breads was evaluated by recording the changes in crust and crumb texture characteristics using the puncture and TPA tests, respectively, as well as the changes in their moisture contents between fresh (0 day) and stored (4 days \(\times\) 25 \({}^{\circ}\)C) products (Figure 3a-f). As expected, for all bread formulations, storage resulted in decreased crust hardness (Figure 3a) and crumb cohesiveness (Figure 3c), along with increasing values of crumb hardness (Figure 3b) and chewiness (Figure 3d), all associated with bread staling events. These changes are attributed to the transfer of water from the crumb to the crust, as shown by the increase in crust moisture content (Figure 3e) and the decrease in crumb moisture (Figure 3f) upon storage for all tested breads. However, stalling process can also be promoted by the re-distribution of water at the molecular level among the various ingredients present in the bread matrix, leading to gluten transition from a rubbery to a glassy state as well as retrogradation of the amylopectin molecules (reordering of starch chains) that can also contribute to a more compact and stiff gluten-starch composite network and thus, to a harder bread crumb structure [32; 33; 34; 35].  
In most cases, the presence of plant solid waste residues in both fresh and stored breads did not have an impact on their crust hardness (Figure 3a) and crumb cohesiveness (Figure 3c), which are indices of crust crispness and crumb friability, respectively. On the other hand, the inclusion of oregano and spearmint waste at 2% level and lemon balm at both supplementation levels resulted in harder crumb. Compared to control, this adverse effect was eliminated during storage, resulting in similar crumb hardness for all tested breads after 4 days of storage (Figure 3b). Additionally, the crumb chewiness of the fresh fortified breads was significantly higher than that of control, except for the rosmary waste-containing bread at both fortification levels, while at the end of the storage period, all SWAP-containing breads, except ROS1%, exhibited higher crumb chewing values than control product (Figure 3d).  
Variability in crumb textural attributes among the tested samples can be ascribed to differences in the water re-distribution and the accompanying phase transition events occurring upon staling in both gluten and starch at a molecular level. Wastes of aromatic plants are rich in dietary fibers, such as cellulose, hemicellulose, and lignin [14; 17], which could increase the water-holding capacity of bread or compete for water with the starch component in a composite bread matrix and, thus, decrease starch retrogradation; both these processes contribute to a softer crumb. On the other hand, fibers can also compete with wheat proteins for water or interrupt or/and dilute the gluten network and, therefore, reduce its water retention capacity, leading the gluten to a glassy state and, finally, to crumb hardening [35; 36]. Crust and crumb moisture contents of all SWAP breads did not  
Figure 2: Loaf specific volume of wheat breads fortified with 1 and 2% oregano (ORE), rosmary (ROS), lemon balm (LEB), and spearmint (SPE) post-distillation solid waste residues; mean values with a different letter are significantly different (Tukey’s test, \(p\) < 0.05).  
significantly differ in the freshly made products (Figure 3e,f). However, after 4 days of product storage, the crust of ORE- and SPE-containing breads, as well as the crumb of all SWAP-breads, except ROS-containing samples, displayed higher moisture contents than the respective control; this is probably due to the presence of dietary fibers in the plant waste materials and their high capacity for water absorption.