Generally speaking, the more protein, the easier becomes the drying. With increased protein content, the viscosity of the concentrate will increase and, to maintain good atomization, it is necessary to reduce the solids content. Drying economy is thus reduced, as a pure protein product (egg white, Na- or K-caseinate) is dried from a feed of 20-24% solids, and the final product consists of single particles.
Proteins are difficult to agglomerate (no binding material) in conventional dryers. The Multi-Stage Dryer is therefore selected, if agglomerated powders are aimed at.
Hydrolysed proteins are generally more difficult to dry, as the short-chain molecules become thermoplastic and hygroscopic, which makes the product stick to the drying chamber walls.