Application of High-Intensity Ultrasounds to Control the Size of Whey Proteins Particles

In this paper, we reported a new method to prepare whey protein microparticles via high-intensity ultrasound disruption. Particles morphology was characterized by confocal microscopy, and their size and distribution were analyzed by light scattering technique. Starting whey protein isolate (WPI) exhibited changes in size and distribution according to its concentration. For WPI, 7.5% (w/w) mean size was 0.7 μm, and upon sonication at ambient temperature, the size was reduced up to 0.2 μm showing the particles a rounded morphology. Sonication at room temperature of gelled WPI led to particles with sizes between 0.1 and 10 μm which had a tendency to flocculate. When WPI was submitted to sonication under heating at protein denaturation temperature, different effects were observed according to protein concentration. The particle size was reduced for the lowest WPI concentration (7.5 wt.%), did not change at 9 wt.%, but strongly increased at 12 wt.%, in comparison with the untreated sample. WPI particles of desired size in the micron range may be obtained either by sonication of gelled WPI or by sonication under heating at denaturation temperature by controlling processing variables.