Improving texture perception in low-fat high-protein yogurts thanks to whey protein aggregates

The demand for low-fat high-protein yogurts has increased substantially over the past years. However,manufacturing protein rich yogurts often results in rubbery mouthfeel and firmer products. Wheyproteins are denatured during heating of milk leading to the formation of whey protein aggregates(WPA) able to interact with caseins during acidification. The rise of whey protein concentration inyogurts comes along with a tighter and denser protein network which can be detrimental for textureperception. The objective of this study is to produce targeted WPA from native Whey Protein Isolate(WPI) through a controlled process to obtain protein-rich yogurts with satisfying texture properties.In the present study, low fat set style yogurts were prepared adding three concentrations of extra WPIor targeted WPA. Either monodisperse or polydisperse WPA populations were studied. Sensorycharacteristics of these nine yogurts were assessed by free sorting by naïve panelists (n=32). Textureperception was related to rheological properties and instrumental texture measurements of yogurts.Sensory results clearly showed that the addition of WPI and WPA increased yogurt firmness. Mostinterestingly, it appeared that for the same concentration, the type of whey protein added had asignificant impact on texture perception. Yogurts enriched in WPA were described as creamy andunctuous whereas yogurts enriched in WPI were brittle and compact. The rheological results, and inparticular the flow measurement parameters confirmed this trend. Moreover, using monodispersesmall WPA instead of polydisperse WPA was a way to increase yogurts’ firmness while keepingunctuousness. Incorporating WPA in low-fat high-protein milks is a promising way to modulate textureperception of yogurts. This is interesting to develop fresh dairy products with special functionalproperties while maintaining a good sensory experience for the consumers. Further research couldfocus on high-protein yogurts with desirable texture properties for the elderly.