## 3 Results and Discussion
### Rheological Properties of the Doughs  
The influence of oil addition and further substitution by emulsion on the thermo-mechanical behavior of the white wheat flour used to prepare the muffin samples was investigated by means of the Mixolab device, which allows for registering the torque of the dough while subjecting it to dual mixing and thermal constraints. The typical Mixolab curve showing the thermo-mechanical behavior of the white wheat flour, used as a basis in the batter formulations, is presented in Figure 4a. The WA of 59.3% was used to get the target torque value C1 of 1.1 Nm. The addition of sunflower oil caused some important changes to the thermo-mechanical behavior of the dough (Figure 4b). The main consistency values were significantly lower (\(p\) < 0.05) compared to those measured for wheat flour with no oil addition (Table 2). The reduction of the torque values registered by Mixolab on the dough with the addition of sunflower oil was previously reported by [PERSON] et al. [26]. Moreover, they showed that oil addition resulted in lower WA values required to reach the target C1 of 1.1 Nm. In the case of our experiment, in order to actually measure the effect of oil and emulsion addition on the thermo-mechanical behavior of the dough, the optimum WA level of 59.3% measured for the white wheat flour was used for preparing all the dough samples. Thanks to the lubricating effect of the oil, softer consistency of the dough is obtained even at low water addition levels [27]. It is generally accepted that, when starch gelatinization occurs in the presence of lipids, the amylose-starch complexes have lower viscosity [28]. The maximum consistency registered for the oil-containing dough sample at 30 \({}^{\circ}\)C (C1) was 0.23 Nm, significantly lower compared with C1 of 1.08 Nm (\(p\) < 0.05) obtained for the white wheat flour sample. The increase of the temperature up to 45 \({}^{\circ}\)C resulted in the rapid drop of the torque measured on the oil-containing sample, indicating the impossibility to record the dough resistance by Mixolab, most probably occurring as a consequence of dough sliding on the mixing paddles when adhesion ceased. A similar rapid torque falling to zero was recently reported by [PERSON] et al. [29] when registering the Mixolab curve of the wheat dough with high oil content. This behavior of the dough suggests that oil addition might interfere with gluten proteins interaction, resulting in softer networks. Figure 3: Evolution of the apparent viscosities as a function of shear rate for the emulsions prepared with soy proteins (light gray), lupin proteins (dark gray), and yeast proteins (black). Further increase of the temperature up to 80 \({}^{\circ}\)C caused the rise of the dough consistency up to C3 of 0.42 Nm, which is five times lower compared with the C3 measured on the wheat flour, therefore suggesting limited gelatinization of the starch. Our observation is in agreement with the previous findings of [PERSON] et al. [30] and [PERSON] et al. [28], who showed that the formation of the starch-lipid complex might interfere with starch swelling, resulting in the reduction of peak viscosity. Finally, the C4 and C5 torque values registered on the oil-containing dough, when heating at 90 \({}^{\circ}\)C and further cooling to 50 \({}^{\circ}\)C, were significantly lower (\(p<0.05\)) compared with the white wheat flour (Figure 4a,b). The lower values of the C3-C4 parameter suggest the improvement of the hot starch paste stability upon oil addition (Table 2). An additional distinctive characteristic of the oil-supplemented dough consists of the low C5-C4 value, suggesting increased resistance to starch retrogradation. Amylose-lipid complexes, formed when starch gelatinization occurs in the presence of lipids, are known to inhibit the retrogradation phenomenon [28].