# The Effect of Inulin Addition on Rice Dough and Bread Characteristics
## 3 Results and Discussion
### Effect of Inulin on Bread Characteristics  
Baking losses represent the amount of water evaporating from dough during baking and cooling. The values of this parameter rose with an increasing amount of added inulin in samples with 0%, 5%, 10%, and 20% inulin, reaching the maximal value in bread containing 30% inulin (18.5%) (Table 2). The bread containing 40% inulin exhibited a lower value (17.1%). Water plays an important role in bread baking. It is used to hydrate proteins and starch granules during dough mixing. During baking, water is released from denatured proteins and is used for gelatinizing a part of the starch granules [17]. Since the flour was replaced by inulin in the tested samples, the content of starch was lower in these doughs than in the dough made from pure rice flour. Water released from denatured proteins might be used for starch gelatinization or might evaporate. Since the addition of inulin shifted the gelatinization temperature to higher values, a part of the water released from denatured proteins could not be used for starch gelatinization, evaporating from the dough, which was recorded as an increase in baking losses. Gelatinized starch plays a role in retaining gas in the dough and preventing bubbles from coalescing during the baking process [40]. This impacts the bread volume and breadcrump porosity. The loaf's specific volume generally increased with an inulin content in the range of 0-30%, reaching a maximum in the bread with 30% added inulin (1.48 mL/g). A similar effect of inulin was observed in gluten-free breads prepared from blends of corn and potato starch, as well as in wheat bread. However, the addition of inulin did not exceed 12% in these studies [26; 41; 42]. The authors explained these observations as a competition between inulin and starch for water during baking. The decrease in water availability retards starch gelatinization, resulting in a delay in the formation of a viscous gel and solid-like behavior in the dough. Prolonged formation of the solid-like dough structure allowed for accumulation of the leavening gas in doughs, even at higher temperatures, until the yeast was inactivated. This effect increased with the addition of inulin. The considerable delay in gelatinization observed in the sample with 40% inulin (Figure 1) shifted the formation of solid-like dough structures to temperatures where the yeast was already inactivated, resulting in a significantly lower loaf-specific volume (1.16 mL/g). Even though the loaf-specific volume increased in the bread with 5-30% added inulin, this parameter remained lower than in wheat bread with added inulin [41]. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline
**Inulin** & **Loaf-Specific Volume** & **Baking Losses** & **Hardness** & **Springiness** & **Cohesiveness** & **Resilience** & **Adhesiveness** & **Cheviness** & **Porosity** \\
**(\%)** & **(mL/g)** & **(\%)** & **(N)** & **(\%)** & **(\%)** & **(\%)** & **(\%)** & **(N s)** & **(\%  
The presence of up to 30% inulin also had a positive effect on the crumb porosity. This parameter increased with the increasing content of inulin, reaching a maximum value in the bread containing 30% inulin. A similar positive effect from inulin was also observed in breads with 4-12% added inulin [26; 42]. The formation of pores may be related to changes in dough gelatinization initiated by inulin. The shift in gelatinization temperature and viscosity changes recorded in doughs with 5-30% added inulin resulted in a better ability of these doughs to accumulate leavening gas inside the pores than that recorded in dough made from pure rice and dough with 40% added inulin. The changes in dough characteristics initiated by the presence of 40% inulin were too extensive, rendering the dough unable to accumulate leavening gas and creating smaller pores (Figure 2f). The greatest difference between the size of the pores situated in the inner and outer parts of the crumbs was observed in the bread without added inulin.