# Innovations in Wheat Bread: Using Food Industry By-Products for Better Quality and Nutrition
## 3. Dough Rheology  
The utilization of by-products from plant food production, acting as natural raw materials rich in dietary fibers and antioxidants, provides an avenue for developing functional foods while concurrently promoting the valorization of generated by-products. However, the partial substitution of wheat flour in bread formulation with these fiber-rich ingredients leads to modifications in dough rheology, consequently affecting the properties of the final product [Table 1]. An in-depth comprehension of the rheological properties of wheat flour dough is crucial for bread producers striving to attain high-quality bakery products. Therefore, these properties must be meticulously considered to ensure the production of bakery items, such as bread, of superior quality. Water absorption, in the context of dough preparation, denotes the quantity of water necessary to attain the desired consistency. This parameter is influenced by various factors such as the starch, damaged starch, protein, pentosan content, and the gluten network within the dough [72]. By-products like fruit pomaces and oil cakes, rich in dietary fiber and containing numerous hydroxyl groups in their structure, tend to form hydrogen bonds with water. Consequently, they enhance water absorption during dough preparation [18; 20; 103]. This increased water absorption can influence various dough properties, including texture, handling characteristics, and final product quality, often indicating good baking performance [18; 104]. [PERSON] et al. [20] and [PERSON] and [PERSON] [105] observed such increases in water absorption after adding grape pomace (up to 10%) to wheat flour. [PERSON] and [PERSON] [105] also found that the type of grape pomace (red or white) could significantly impact changes in water absorption, while particle size showed no influence. Similarly, [PERSON] et al. [106], [PERSON] et al. [103], and [PERSON] et al. [107] reported similar increases in water absorption when adding apple pomace (up to 25%), attributing this effect to the rehydration properties of dried apple pomace. According to [PERSON] et al. [107], a higher water content in wheat dough could enhance the organoleptic properties of bread, such as taste. Moreover, the studies conducted by these authors, similar to the results presented by [PERSON] and [PERSON] [105], did not demonstrate any impact of varying degrees of pulverization of apple pomace on the water absorption of wheat dough. In the case of by-products from oil extraction, [PERSON] et al. [18] and [PERSON] et al. [17] observed increases in water absorption for wheat dough supplemented with olive pomace and flaxseed cake up to 15%, respectively. [PERSON] et al. [19] found a similar increase in water absorption for flaxseed cake supplementation up to 50%. Conversely, [PERSON] et al. [108] and [PERSON] et al. [109] observed that the addition of ground whole flakseed caused a decrease in water absorption (WA) of the dough. This decrease was mainly attributed to gluten dilution, requiring lower amounts of water to achieve the optimal consistency, and the higher content of oil, which can coat both starch and gluten, leading to a reduction in water absorption. In the study conducted by [PERSON] et al. [72], a reduction in water absorption was noted as the supplementation levels of olive pomace increased, particularly with additions exceeding 2%. They utilized freeze-dried powder (<500 um) obtained from olive pomace (from two olive cultivars) to supplement wheat flour. The authors attribute this behavior to the softer texture of the freeze-dried powder obtained from olive pomace compared to wheat, resulting in a higher water uptake rate and requiring less water to achieve the desired dough consistency. Additionally, the supplementation level used in their study (up to 5%) was low enough not to significantly affect the reduction in starch content, which could otherwise lead to an increase in the required water addition pomace and skimmed apple pomace [107].