# Wheat Bread with Dairy Products--Technology, Nutritional, and Sensory Properties
## 3 Results and Discussion  
### Wheat Dough Extension Properties (WDEP)  
The effect of yoghurt (Yg) and curd cheese (Cc) addition on wheat dough extension properties at 30 \({}^{\circ}\)C after 60 min of fermentation time was studied, and the results obtained are presented in Figure 1. It is clearly observed that the Yg and Cc have different impacts on dough extension properties, most probably due to the different nature and structure of the proteins added--acid precipitated caseins from Yg and soluble whey protein precipitated by thermal denaturation from Cc. The extension properties are positively affected by Yg addition and are adversely affected by Cc incorporations.  
Considering Figure 1A, the dough resistance values were similar to control dough up to 50 g of Yg addition, whereas for 70 g a reduction of about 21% was observed compared to control.  
For Cc additions, all the levels evaluated result in dough resistance values lower than the control, with a significant reduction of about 64% (p \(<\) 0.05) for the highest level of Cc added (83 g).  
From Figure 1B,C, it can be seen that, at 20 g of Yg addition, a steep increase both in extensibility (B) and deformation energy (C) is observed, and remained constant for the rest of the levels evaluated, with higher values compared to the control. Relative to Cc additions, lower values of extensibility and deformation energy than the control dough were observed, except at 30 g of addition, which showed values similar to the control.  
In terms of R/E ratio values, the differences observed for Yg and Cc additions are clearly reflected on Figure 1D. The resistance versus extensibility is an important ratio to evaluate the balance between -down resistance (elasticity) and extensibility (viscosity), and a good combination of both parameters is required to obtain desirable dough properties and bread quality [13].  
Overall, the addition of Yg has a positive impact on the structure of the dough, which was seen by the increase of the extensibility and deformation energy. One can suggest a synergic interaction between the Yg proteins and wheat proteins on the gluten network development. In addition, the presence of the exopolysaccharides produced by the lactic acid bacteria present in yoghurt, can also act on the system as lubricants, together with gliadins, giving more stability and extensibility to the wheat dough. Similar results were observed by other authors [3; 10] who also reported an increase in deformation energy due to the strengthening effect of hydrolyzed caseins and sodium caseinates from the added dairy product.  
However, opposite results were obtained for Cc addition that affected the dough properties in extension, suggesting that denatured whey protein has an antagonistic effect with wheat proteins, strongly affecting the gluten matrix. These results can be attributed to the gluten proteins dilution effect [11; 12] and protein competition for available water, impacting negatively on dough development [19]. Similar results were previously reported by other researchers [10], demonstrating that dairy by-products such as whey protein, in general, reduce the extensibility and the deformation energy.  
Therefore, it can be stated that the Yg addition had no adverse impact on the technology characteristics of the dough, which will have a positive impact on bread quality. The incorporation of the Cc implied a significant reduction on extensibility properties, which would promote a significant depression on bread volume.