The present research was established to study the effect of green tea and Pu-erh tea (PT) additives on the mechanical and hydration properties of yogurt gels using a combination of nuclear magnetic resonance, rheological, and textural studies. Tea infusions (0-15 mL/100 mL) were added to batch milk before fermentation with yogurt culture. Obtained dairy products were analyzed for the water mobility and organization, viscosity, and texture profile. Results of the rheological and nuclear magnetic resonance studies suggested that stabilization of the yogurt gel structure was achieved upon supplementation with tea infusions. Generally, green tea fortification produced yogurts with more consolidated gel structure, tighter interacting water, and less susceptibility to shearing and temperature changes than PT treatments. In contrast, PT yogurts were more viscous and characterized by 8 to 17% lower hardness values. This knowledge can be useful for developing novel dairy products with desired structure and consistency.

A protein isolate (85.5%) was obtained from the Vicia faba L. seeds. The main protein fraction, typical for the seeds of this plant, was found to be most numerous: Legumin (35 kDa) and Vicilin (45 kDa). The hydrodynamic and surface properties of isolate aqueous solutions were studied with the help of dynamic light scattering, $\zeta$-potential, and tensometry in a wide range of concentrations and pH conditions. Selected functional properties, like foaming and emulsifying abilities, were studied. An increase of water solubility was shown with a raising pH, as well as a water holding capacity (WHC). The protein isolate showed a tendency to decrease the surface tension of water solutions, with high hydrophobicity and a negative charge of the isolate enhancing the foaming and emulsifying properties. The analysis of the concentration and the pH influence on selected functional properties indicated alkaline conditions as favorable for good foaming and emulsifying properties of the isolate and affected on their rheological properties.