Drying kinetics of calcium caseinate

Drying is a major component of the cost of making caseinate-based films. We determined the drying curves for making calcium caseinate/glycerol films at low and high relative humidity at 21-34degreesC. The drying curves exhibited a very long constant rate period followed by a single falling rate period. Much of the drying was in the constant rate period and preceded the actual film formation. Normally, calcium caseinate solutions are dried from about 5% solids, but it was possible to start with a more concentrated solution, 10% solids, to avoid much of the constant rate period. The resulting films were equal to those prepared starting at high initial moisture. An estimate of the drying costs indicated it is much cheaper to start with the more concentrated solutions.