## 3 Results and Discussion  
In the first part of the experiments, we analyzed the dielectric and rheological behavior of raw milk samples when they undergo enzyme-induced coagulation, and the correlation between the changes in dielectric parameters and the apparent viscosity was investigated. Our preliminary results show that the change in dielectric parameters was higher at lower frequencies; therefore, the dielectric constant was depicted at a frequency of 400 MHz. Figure 2 shows the variation of the investigated characteristics in the function of time. Based on the experimental data gathered, it can be observed that the enzyme-induced coagulation of milk follows a similar trend for both the change in the apparent viscosity and the change in dielectric constant as a function of time. During the initial phase, both viscosity and dielectric constant remain relatively constant, which indicates that the coagulation process is in its initial stages, with the enzyme slowly breaking down the milk proteins and the formation of the protein network just beginning. Starting from 10 min, both the viscosity and the dielectric constant show a rapid increase in their values. This suggests that the coagulation process is accelerating, and the protein network is forming at a faster rate. The \(\kappa\)-casein protein, which provides stability to the casein micelle, is being hydrolyzed by the enzyme, resulting in the formation of a glucomacropeptide and a para-\(\kappa\)-casein fraction released into the whey [22]. This means that the steric repulsion ceases between the hydrophobic para-casein micelles due to their lack of negative surface charge, and they begin to bind together. The increase in viscosity is attributed to the formation of a more substantial and rigid network of proteins, which slows down the flow of the liquid. Similarly, the rapid increase in dielectric constant is due to the formation of a more complex and continuous network of proteins that can absorb and store the electromagnetic energy better. The study by [PERSON] et al. concluded that the dielectric parameters of proteins are influenced by their structural changes and the change in the interaction between the proteins and the surrounding medium [23]. At around 25 min, the dielectric constant reaches its maximum value, while the apparent viscosity marks its highest point at 30 min. Afterward, both become relatively constant, with a slight decrease observable in both of them, which might be due to the syneresis of the clot. This indicates that the coagulation process has  
Figure 2: Change in apparent viscosity (\(\eta\)) and dielectric constant (\(\epsilon^{\prime}\), f = 400 MHz) versus time during the enzyme-induced coagulation of raw milk. reached its completion with the protein network being fully formed, i.e., the point of clot solidification occurs. With this stable state, no observable physicochemical changes take place anymore, which results in no significant changes in the dielectric properties (Figure 2). The pH of the sample during the final/stationary phase was measured to be 6.0 \(\pm\) 0.05. The alteration or modification of casein micelles can occur, of course, due to other factors or treatment processes too. In a 2021 study, [PERSON] et al. showed that the coagulation of casein micelles can happen under the action of Zn\({}^{2+}\) ions originating from organic chelated Zinc compounds [24], while others reported that different pre-treatment methods, such as ultrasonication [25], high pressure, and/or thermal treatments [26; 27] can significantly affect (accelerate the process or make the aggregates bigger, for example) the aggregation of the micelles. These molecular-level processes can be investigated or monitored through different analytical methods, such as photon correlation spectroscopy [24], small deformation rheology [25], gel permeation chromatography, or HPLC [26], but it is worth mentioning that sol-gel transformation and coagulation mechanisms can be precisely analyzed using dielectric measurements as well [28].