Mitigating the Astringency of Acidified Whey Protein in Proteinaceous High Internal Phase Emulsions

The demand for high-protein food products has rapidly increased in recent years because of the growing health awareness of consumers. Whey protein is an abundant byproduct from the dairy industry with a high nutritional value. However, it is a substantial challenge to mitigate the astringent taste in acidified whey protein food products. Water-in-oil (W/O) emulsion with a high internal aqueous phase represents a unique opportunity to simultaneously deliver the high concentration of whey protein and mitigate the astringent taste in spreadable foods. To incorporate protein into the high internal phase emulsion (HIPE), whey protein-polysaccharide complexes (PPCs) are formed to minimize destabilization of the emulsion. Such whey PPCs are found to not only stabilize protein but also play a role in mitigating astringency. The protein astringency is studied through real-time monitoring of the protein-saliva mucin interaction on a quartz crystal microbalance. Our results showed that PPC showed less mucin interaction compared to whey protein and preventing protein-mucin interaction can lead to decreased astringency perception. By fabricating the PPC into the HIPE, the astringency of protein can be further minimized with improved protein loading capacity (20 wt %) and viscoelasticity (10³-10⁴ Pa). Incorporation of whey protein at acidic pH in W/O HIPE imparts advantages, such as decreased protein degradation as well as increased emulsion spreadability and stability. Furthermore, the resultant emulsions are less astringent in sensory studies, indicating HIPE's potential to integrate acidified whey protein at a high concentration with a low astringency profile.