The effect of whey protein concentrate as a fat replacer on the rheological characteristics of yogurt

The aim of present study was to evaluate the effect of adding whey protein concentrate (WPC) as a fat replacer in the rheological properties of yogurt. Whole yogurt and nonfat yogurt with 0 %, 1.5 %, 3.0 % and 4.5 % of WPC were developed and available. The steady and dynamic shear rheological properties were determined using a HAAKE MARS rheometer at 10 °C with a sensor stainless steel double gap cylinder system DG41 and a sensor cone-plate C60/1° (60 mm diameter), respectively. Results revealed that the yogurt exhibited non-Newtonian and shear thinning behavior. The Bingham model was fitted satisfactorily to the experimental data of curve flow. The addition of WPC resulted in an increase of the storage modulus, G’, in the frequency range tested, indicating that the whey protein concentrate has contributed to the gel matrix. Yogurts containing 3.0 and 4.5 % of WPC and whole yogurt showed the same profile of dynamic modulli, presenting a more elastic than others with lower levels of WPC. This indicates that yogurts with 3.0 % and 4.5 % of WPC shown a rheological behavior similar to whole yogurt and these levels of WPC were effective as a milk fat replacer in yogurt.