## 3 Results and Discussion
### Dynamic Rheological Study of Yogurt Samples  
The microrheological characterization reported above allowed us to effectively analyze the rheological behavior of the samples at rest and the phase transition from milk to a yogurt-like structure, without altering the analyzed samples. Unfortunately, this particular method is not suitable to describe the rheological behavior of the samples when they are manipulated. Samples such as yogurt-like structures are handled during storage, transport and consumption by the consumer, and these manipulations could modify the structure and the texture of samples, risking to be no longer pleasant. For this reason, we chose to associate the microrheological characterization with dynamic rheological studies. Thanks to Kinexus Pro+ rotational rheometer, the rheological parameters (G' and complex viscosity) of yogurt-like structures made with different vegetal milk and different amount of carob seed flour were obtained in function of frequency and storage time. In general, the complex viscosity (n*) corresponds to the total resistance of a sample to flow as a function of frequency [37] and we wanted to evaluate the effect of carob seed flour on the sample's ability to resist or change following the induced oscillation. Figure 2 shows the rheological results of the samples in terms of frequency dependence of the complex viscosity. Generally, the viscosity decreased as a function of an increasing frequency when the sample moved faster with applied force, and the reduction in viscosity was a consequence of a reduction in interactions between the components of sample [38]. Observing Figure 2, we can note that, independent of storage time, all samples prepared with soy milk and with or without carob seed flour respond to the applied force with a reduction in their viscosity, highlighting a pseudoplastic fluid nature, as already demonstrated by [PERSON] et al. [39]. In our study, immediately after preparation (time 0 of storage), the viscosity of soy-milk-based yogurt-like structure sample prepared without any concentration of carob seed flour was characterized by a starting complex viscosity at low frequency higher than the sample containing 1% of carob seed flour; the slope of the sample without the carob seed flour curve is visibly the steepest of the other samples, indicating that the interactions between the components of this sample of soy-milk-based yogurt-like structure. During the following days of storage of soy-milk-based yogurt-like structures, carob seed flour seems to stabilize the network. In the presence of a high amount of carob seed flour (0.75% and SM + 1% respectively), the complex viscosity did not change when samples were subjected to a variation of oscillation frequency, thanks to the viscoelastic properties of caroubin [22]; on the contrary, the sample without carob seed flour underwent a considerable reduction in viscosity values during the rheological test, resulting in it being much more sensitive to rheological stresses. In fact, the difference in terms of complex viscosity data between SM + 0% and CSF samples became statistically significant after 2 days of storage and at high CSF concentration (\(p<0.001\)). These findings can be due to the entrapment of soy milk proteins between the meshes of the network, and, when carob seed flour amount is increased, probably, the meshes become narrower, and complex viscosity is not affected by the applied stress. Figure 2: Complex viscosity (Pa-sec) versus frequency (Hz) for yogurt-like structures made of soy milk and increasing concentration of carob seed flour. The samples were analyzed at time 0 (**A**), 24 h (**B**), 48 h (**C**) and 5 (**D**) days of storage. The illustrated results were representative of three independent experiments. Soy milk is characterized by high protein content (3.3 g/100 mL) in respect to almond (0.5 g/100 mL) and coconut (0.1 g/100 mL) mills.