High-pressure microfluidization of whey proteins: Impact on protein structure and ability to bind and protect lutein

Dynamic high-pressure homogenization microfluidization (DHPM) is a versatile emerging technology that may be applied to food processing to achieve several goals. DHPM may, depending on nature of the molecules and the working parameters, induce changes in protein structure, which may improve or impair their techno-functional properties and ability to bind other molecules. In this context, DHPM (12 passes, 120 MPa), coupled or not to a cooling device, was applied to β-lactoglobulin (β-lg) and whey protein isolate (WPI) dispersions. Minor changes in the structure of whey proteins were induced by DHPM with sample cooling; although, when sample cooling was not applied, aggregation and increases of around 30% of protein surface hydrophobicity were noticeable for the WPI dispersion. The association constant between the proteins and lutein was in the magnitude of 10⁴ M^-1, and lutein photodegradation constant diminished about 3 times in the presence of proteins, compared to in their absence.