## 3 Results and Discussion
### Dynamic Rheological Study of Yogurt Samples
These data, reported on the label of the used vegetal products, could explain the different rheological behavior and the different complex viscosity values of almond- and coconut-derived yogurt-like structure samples, in respect to soy-derived products. Figure 3 reported the rheological behavior of almond-milk-based yogurt-like structures as complex viscosity curves vs frequency. Observing the figure, we can see that the presence of high carob seed flour concentrations permitted the stabilization of yogurt-like structures. In fact, the complex viscosity of almond milk containing a decreasing amount of carob seed flour (1%, 0.75% and 0.5% carob seed flour) was not affected by storage time and it was maintained almost constant during 5 days. These findings are in agreement with Rheolaser Master(tm) results. Moreover, we can observe that the slope of the complex viscosity curves of almond-milk-based samples is much less marked when the frequency of oscillation is increased, in respect to the slope of soy-milk-based yogurt-like structures curves. These results showed that the samples responded to the applied stress by modifying its complex viscosity only slightly. We can affirm that carob seed flour does not lead to a marked increase in complex viscosity but it permits to obtain a three dimensional network more resistant to applied stress, compared to what happens with soy milk. In any case, the complex viscosity data of AM + 0% are significantly lower (\(p<0.001\)) than the values obtained for samples prepared with increasing concentration of CSF. In the case of almond-based yogurt-like structures, the importance of carob seed flour for obtaining a good product was confirmed after 5 days of storage. As we can see, in Figure 3D, the complex viscosity curve of the sample containing almond milk without carob seed flour is missing, because the sample after 5 days of storage showed an evident phase separation, as already mentioned, and,  
Figure 3: Complex viscosity (Pa-sec) versus frequency (Hz) for yogurt-like structures made of almond 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. for this reason, the rheological characterization of this sample was not carried out. The absence of carob seed flour does not permit the construction of a solid three-dimensional network that stabilizes the yogurt-like structures. The rheological characterization of coconut-based yogurt-like structures obtained using increasing carob seed flour concentrations gave similar results to those of the almond-based samples. In fact, the starting complex viscosity of all coconut-milk-based samples was near to the starting complex viscosity values of almond-milk-based samples. Moreover, their rheological behavior highlights a slight dependence of complex viscosity on frequency variation; in fact, we can see in Figure 4 that the slope of complex viscosity curves is reduced when compared to the complex viscosity curves of the soy-milk-based samples. Moreover, in the case of coconut-milk-based samples, the complex viscosity data obtained for CM + 0% CSF are statistically significant with respect to the samples prepared with CSF (\(p<0.001\)), independently of time storage and CSF concentration. We supposed that the similarity of results given by almond-milk- and coconut-milk-based yogurt-like structures was due to the similar protein content of both vegetal milks. Changes in G\({}^{\prime}\) values (storage modulus, Pa) of different vegetal-milk-based yogurt-like structures during storage for a period of 5 days are reported in Figure 5. G\({}^{\prime}\) is a rheological parameter that represents the elastic behavior of the sample. It corresponds to a measure of deformation energy stored in the sample during shear process [34; 40].