# Effect of Citrus Fiber on the Rheological Properties of Dough and Quality of the Gluten-Free Bread
## 3 Results and Discussion
### Crumb Texture  
Measurements of the variability of parameters characterizing the texture during the storage of bread allow the assessment of its stability and the influence of various types of ingredients or additives on its characteristics. During the storage of bread, especially gluten-free bread based on starches of various origins, a number of structural changes, referred to as \"staling\", may occur, reducing consumer acceptance of such a product. In order to limit this phenomenon, a number of modifications in recipes or technology could be applied to introduce ingredients or additives controlling water retention, modifying the structure of starch polymers and limiting retrogradation [5; 10]. The parameters characterizing the texture of control bread and samples with citrus fiber are presented in Table 3.  
Figure 4: Images of control gluten-free dough (**a**) and samples with citrus fiber 10% (**b**), 15% (**c**) and 20% (**d**). On the day of baking, the crumb of control bread and loaves with 10-15% fiber content had the highest hardness. Only the replacement of starch with 20% fiber and corresponding increase in water addition caused a significant decrease in crumb hardness. During storage, the hardness of the loaves increased. The highest increase in hardness to over 7 N was observed in the case of the crumb of control bread, which clearly showed gradual staling. On the other hand, the crumb of loaves with the share of citrus fiber aged much slower, reaching on the third day of storage a hardness ranging from 3.94 N in the case of bread with the highest 20% share of fiber to 5.45 N in the case of bread with the lowest 10% share of fiber. The extent of crumb hardening retardation was clearly dependent on the amount of starch replaced by the fiber. It is also confirmed here by the results of the two-factor analysis of variance, where both the time and the share of fiber significantly affected the crumb hardness of bread (Table 3). Moreover, a negative linear correlation (r = \(-\)0.97) between crumb hardness and porosity was observed. Additionally, [PERSON] and [PERSON] [13] observed a significant decrease in gluten-free bread hardness after applying fiber preparations of various origins. A significant reduction in crumb hardness resulting from the presence of highly water-absorbent citrus fiber and, consequently, an elevated proportion of water in the recipe indicates that this ingredient, in addition to a significantly increasing the nutritional value of gluten-free bread, may be an effective factor-limiting staling process. The share of citrus fiber in the recipe and storage time also influenced the elasticity of the crumb of the analyzed bread. On the first day, all samples were characterized by the same elasticity. During storage, the elasticity of the crumb decreased when more fiber was introduced into the recipe. Due to the fact that fiber has a high ability to bind water, which also forces its greater share in the recipe, the crumb of the resulting bread becomes more moist, soft and susceptible to plastic deformation. The values of cohesiveness of the bread samples are presented in Table 3. Both the storage time and the level of fiber contribution had a significant impact on the cohesiveness values. The control bakery products were characterized by the highest cohesiveness both on the day of baking and during storage. Replacement of starch with citrus fiber resulted in a decrease in cohesiveness when more fiber was introduced into the recipe. In earlier studies, [PERSON] and [PERSON] used citrus fiber in combination with microfluidized corn gluten meal (CGM) in order to improve the quality of gluten-free bread.