Yoghurt cultures (0.1, 1.5 and 3.5% fat) were prepared from milk which was preheated to 45 C and subjected
to thermosonication (TS) for 10 min at an ultrasound amplitude of 24 kHz. Compared to conventional
yoghurts prepared from preheated (90 C, 10 min) milk, cultures from TS milk at similar fat
contents had higher gelation pH values, greater viscosities and higher water holding capacities (WHC).
On average, yoghurts from TS treated milks with 1.5 or 3.5% fat had almost 2 fold greater WHC and
25% higher G’ values than conventionally produced yoghurt. Electron microscopy showed differences
in the microstructure, with TS yoghurt having a honeycomb like network and exhibiting a more porous
nature. These characteristics are absent in conventional yoghurts. In addition, the average particle size in
TS yoghurts was smaller (