# Innovations in Wheat Bread: Using Food Industry By-Products for Better Quality and Nutrition
## 4 Head Quality
### Texture
[115] investigated the effect of adding two types of flaxseed marc flours (roasted and unroasted) on fresh and 24-h stored bread. As shown in their study, both fresh and stored bread exhibited a significant decrease in hardness with the addition of flaxseed cake up to 15%, which the authors related to its high water-holding ability. Such trends confirm the previously demonstrated ambiguous influence of increased water-holding capacity on hardness changes, which are simultaneously influenced by other factors [45; 120]. In this case, a 15% addition of flaxseed cake (both roasted and unroasted) resulted in an increase in lipid content, specific volume, and changes in crumb structure (lower cell diameter and thinner cell wall) compared to the control. This could also contribute to the decrease in hardness. It was shown that lipids present in flaxseed cake can promote a softer texture and prolonged freshness. The significant impact of specific volume on hardness changes is supported by the observed increase in hardness with a 25% flaxseed addition, which was accompanied by a reduced specific volume of the bread. However, it is important to emphasize that in each case, the hardness of the supplemented bread was either lower or did not significantly differ from the control sample. Changes in the proportion of flaxseed, regardless of the type, only slightly affected the crumb springiness and cohesiveness, with a noticeable decrease in springiness observed only in the case of fresh bread with a 25% addition. The minor impact of flaxseed cake addition (up to 15%) on springiness, cohesiveness, and chewiness is also confirmed by studies conducted by [PERSON] et al. [17]. No significant changes in bread hardness were observed after 24 h. However, after 72 h, the bread with added flaxseed exhibited approximately 30% higher hardness compared to the control sample. The reduction in bread hardness noted by [PERSON] et al. [115] is consistent with the findings of [PERSON] et al. [126] using flaxseed residue (at 4% and 8%). These results also confirm the minor impact of the addition on springiness and cohesiveness. However, contrary to the results presented by [PERSON] et al. [17], a decrease in chewiness was noted. [PERSON] et al. [26] examined the impact of olive pomace on the hardness of bread made from white and whole wheat flour, fortified with fresh and stored olive pomace for 6 weeks at different temperatures (\(-4\)\({}^{\circ}\)C and \(-20\)\({}^{\circ}\)C). Fresh olive pomace up to 15% decreased bread hardness, but at 20%, hardness increased, although the values remained below the control sample. This trend was consistent with the observations made for flaxseed pomace by [PERSON] et al. [115]. Refrigerated olive pomace showed similar hardness trends, while frozen olive pomace at 15% and 20% increased bread hardness significantly compared to the non-fortified bread. As the results presented by [PERSON] et al. [26] indicate no significant effect of the addition of olive pomace on the specific volume of the bread, it can be assumed that the changes in texture are mostly affected by changes in fat and dietary fiber content. As indicated earlier by [PERSON] et al. [115], an increased fat content in bread, associated with the type of additive used, can promote a softer bread texture. On the other hand, the increased dietary fiber content may compensate for the fat's impact on reducing hardness, especially at higher olive pomace inclusion levels. The potential influence of lipid content on bread hardness is also supported by the research of [PERSON] et al. (2018). The authors demonstrated that when using defatted olive pomace, there is an increase in bread hardness (at 24 h) compared to the control sample, with a statistically significant increase observed only at a 15% inclusion rate. Additionally, the addition of defatted olive pomace had a minimal or no significant effect on adhesiveness, resilience, springiness, cohesiveness, and chewiness of the bread (at 24 h).