Rheology and microstructure of low-fat yoghurt produced with whey protein microparticles as fat replacer

The effect of ten microparticulated whey protein preparations with different chemical and physical characteristics upon the rheology and microstructure of stirred low-fat yoghurt (0.5%, w/w, fat) was studied at two total protein levels (4.25 and 5.0%, w/w). Higher ratios of native β-lactoglobulin and α-lactalbumin in the microparticulated ingredients improved the texture of stirred low-fat yoghurt. This was reflected in lower serum separation and a more interconnected and compact protein network with smaller protein aggregates. The improved texture and rheological properties of low-fat yoghurt was only obtained when the whey proteins were added as microparticles and not as part of conventional whey protein ingredients such as whey protein isolate.