# Innovations in Wheat Bread: Using Food Industry By-Products for Better Quality and Nutrition
## 4 Head Quality
### Baking Properties  
The scientific reports confirm an increase in dough and bread yield with the increasing proportion of by-products, although this increase is not proportional to the quantity of the introduced component [17; 114; 115]. This phenomenon could be attributed to the increased water absorption capacity of fibers. Bread yield improved with the increasing amount of water added to the flour [116]. However, even with the same amount of water added to the flour, the bread yield may vary depending on the quantity and type of added flaxseed by-products and their processing (particle size, thermal treatment) [115]. The augmentation in dough absorption holds economic significance. Consequently, the incorporation of oil and fruit by-products into bread formulations could present an added value [117]. The high content of dietary fiber present in flaxseed by-products may promote water adsorption and water retention in bread, contributing to an increase in bread yield. [PERSON] et al. [17] reported an increase in bread yield with the increasing supplementation level of flaxseed cake from 5% to 15%. At the maximum supplementation level, an 8% increase in bread yield was found compared to the control sample. However, a study by [PERSON] et al. [115] indicated that when the addition of flaxseed cake increased up to 25%, this trend can be interrupted. This suggests that an excessive addition of flaxseed cake could lead to deterioration of the gluten network, resulting in reduced water retention in the bread. [PERSON] et al. [115] also demonstrated that the particle size of the introduced component plays a crucial role in the structure and quality of bakery products. Comparing bread yield with a 25% addition of flaxseed cake with different particle sizes showed a higher value in the case of a by-product with a smaller particle size. A smaller particle size allows for better filling of the gluten network, reducing gluten structure damage and thereby retaining more water in the bread during baking. As reported by [PERSON] et al. [118], a decrease in particle size could improve not only the gluten network but also lead to increased gas retention during fermentation. Given the high fiber content and its potential influence on increased water absorption, it can be reasonably expected that in the case of other by-products such as olive, grape, and apple pomace, an increase in bread yield would also occur. Unfortunately, this characteristic was overlooked by the authors of the analyzed studies. Another significant characteristic from an economic standpoint is oven loss and baking loss. These two parameters are associated with water loss during baking and cooling of the bread and, as shown in the analyzed study, depend on several factors such as the type of by-products, level of supplementation, and particle size of the raw material. As demonstrated by [PERSON] et al. [18], substituting wheat flour with olive by-product flour resulted in a significant reduction in baking loss; decreasing from 14.33% observed for the control sample to 11.1% for bread with a 15% inclusion of olive by-products. This observed trend is attributed to the formation of hydrogen bonds between the hydroxyl groups of the dietary fiber structure. As a result, doughs containing a higher fiber content exhibited higher moisture content. This is confirmed by the high negative correlation observed between baking loss and crumb moisture after 24 h (R = \(-\)0.942) and after 72 h (R = \(-\)0.950). [PERSON] and [PERSON] [119], indicated that some water molecules bind to the hydrophilic groups of fibers as bound water, which is more difficult to evaporate during the baking and cooling process, thus limiting the extent of baking losses. Such a reduction in baking loss was not observed when introducing flaxseed cake into bread. The total baking loss did not differ significantly for wheat bread with a 5-15% addition of flaxseed cake compared to the control [17].