Impact of spray drying and storage temperatures on whey protein concentrate rehydration determined using broadband acoustic resonance dissolution spectroscopy

Understanding whey protein concentrate (WPC80) powder rehydration over time is important for those who incorporate powders into food products. Inhibited rehydration behavior and prolonged rehydration time can cause processing challenges and increased production costs. In this study, we investigated how spray drying inlet/outlet and storage temperatures influenced the rehydration behavior of WPC80 powders, elucidating the relationships between particle morphology, powder bulk density, protein modifications and inhibited rehydration. Powder rehydration over time was measured using the novel broadband acoustic dissolution spectroscopy (BARDS) method. This method monitors gas release during rehydration, which occurs simultaneously with water penetration. Powder dried at higher temperatures released more gas and had a prolonged delay before complete dissolution (>990 s) compared with those dried at lower temperatures (730 s). These observed differences can be attributed to contributions from various factors, including alterations in particle size and shape, powder packing behavior, and protein modifications such as protein denaturation and lactosylation. Our findings suggest that both higher spray drying inlet/outlet temperatures, and storage at 40°C for 2 mo may deteriorate rehydration properties.