# Wheat Bread with Dairy Products--Technology, Nutritional, and Sensory Properties
## 3 Results and Discussion
### Evaluation of Bread Properties  
#### 3.2.1 Bread Texture and Aging Kinetics  
The texture of the breads produced with different contents of yoghurt and curd cheese was evaluated in terms of firmness by a puncture test. The determination of firmness during a storage time of 96 h at room temperature was also performed to evaluate the effect of dairy product additions on the kinetics of bread aging (Figure 3A,B) [12]. From Figure 3A,B, it can be observed that both Yg and Cc additions had different impacts on the aging kinetics of the breads.  
Bread aging kinetics was described as a function of the dairy products incorporation, and a positive linear relation (R\({}^{2}\) > 0.98) was observed, with parameters presented in Table 2, and clearly reflect the impact of the different levels of Yg and Cc addition on bread aging kinetics (A, the slope) and firmness (B, the interception).  
As can be seen from Figure 3A,B and the respective linearizations on Table 2, the Yg breads are clearly less firm than Cc breads: the initial firmness of the control bread (1.21 N) is higher than low incorporations of Yg up to 50 g (1.15 N), and for higher replacements (70 g), the firmness is slightly higher (1.39 N) than control.  
Figure 3: Variation of firmness (N) and aging kinetics for breads prepared with different contents of Yg (**A**) and Cc (**B**) addition, replacing the flour in bread formulation, at initial and 96 h of storage time, and respective linear equations: staling rate as crumb firmness with time for the different concentrations of Yg and Cc.  
The Yg breads aging kinetics (A) ranging from \(0.78\times 10^{-2}\) N/h for the 10 g up to \(1.36\times 10^{-2}\) N/h for the 70 g of Yg addition and are similar to control bread (\(0.94\times 10^{-2}\) N/h). In the case of Cc breads, a completely different effect can be observed, i.e., all breads are firmer and the rate of staling is higher than the control bread. The initial firmness up to 30 g of addition is similar to the control, but at 50 g of Cc addition, the increased is about 130%, and at 83 g, it goes up to 330%.  
The rate of staling is also increasing substantially, ranging from \(1.70\times 10^{-2}\) N/h for the 10 g, up to \(3.72\times 10^{-2}\) N/h for the 83 g curd cheese addition, representing an increase of 120%.  
Similar results were obtained in earlier studies [11], indicating that the whey protein significantly increase the bread crumb firmness. Our findings are also in agreement with those obtained by other authors [3; 10] with the addition of dairy products in bread dough formulations.  
This difference in bread texture with addition of Yg and Cc should reflect the complexity of the interactions of the major macromolecules at play and are in agreement with the results observed in extension properties evaluation (Figure 1). Starting from the gluten matrix, when yoghurt is added, some reinforcement of the structure was seen by the increase of extensibility and deformation energy. Values of dough resistance were similar to the control, not interfering substantially on the R/E values. The opposite is observed for curd cheese breads, where R/E values increased steeply, revealing an imbalance of the elastic and viscous components of the wheat dough, clearly reflected in bread texture and aging kinetics.