Buffalo whey proteins performance at the oil/water interface: rheology characterization of the interfacial films

BUSTOS, LEANDRO FABIÁN; VASILE, FRANCO EMANUEL; VICTOR MANUEL PIZONES RUIZ-HENESTROSA; CECILIO CARRERA SÁNCHEZ; PÉREZ, OSCAR EDGARDO

Congreso; 13TH World Buffalo Congress; 2023

Whey proteins have the ability to form thin layers at the interface of non-miscible liquids like oil drops and water by emulsifying. The interfacial activity and the rheology of the interfacial films constitutes a key aspect in the assessment of ingredients ability to form and stabilize emulsions. Despite cow origin WPC has been extensively used in the food industry, the WPC from buffalo (BWPC) are still scarcely studied. In this context, the objective of this work was to explore the interfacial activity and the viscoelastic properties of BWPC at the oil in water (O/W) interfaces. WPC was used for comparison. With this purpose, BWPC and WPC were dispersed at 2.6x10-3 ? 1.6% w/v in 10 mM phosphate buffer (pH 7) and equilibrated at 4 °C for 24 h. Then, the equilibrium interfacial pressure (πeq) was registered through Wilhelmy plate method. Additionally, dynamics of adsorption at the O/W interface at protein concentrations of 0.5 and 1% were obtained over 3 h with a drop tensiometer. Subsequently, the rheological dilatational behavior (10% deformation amplitude and 0,1 Hz of angular frequency) was evaluated. Plate tensiometry showed that πeq of BWPC and WPC solutions increased from 9.9 to 16.7 mN/m and from 11.5 to 15.0 mN/m, respectively conform protein concentration increased. An intersection between  ? concentration isotherms was observed indicating that below protein concentration of 1.3x10-2 % the πeq of WPC was higher than BWPC. This observation could be attributed to compositional differences and the possibilities to generate different structural patterns in the interface. Drop tensiometer displayed that π increased with time for both protein concentrates indicating the protein adsorption at the O/W interface. Interfacial rheology results indicated a gradual increase in the solid or elastic character (Ed) over time for both type of proteins, indicating more cohesive and packed structures. Ed of BWPC was higher than WPC at the lowest protein concentration while the opposite also occurred. This behavior can be explained considering that the higher protein concentration the stronger interactions among BPWC proteins occur. In conclusion, BWPC was able to increase the interfacial pressure to a greater extent than WPC and concomitantly forming films with a higher solid character. These findings contribute to consider the use of BWPC as an efficient emulsifier agent with the benefits of adding value and minimizing the environmental impact of this byproduct.