Foam Spray Drying Methods of Making Readily Dispersible Nonfat Dry Milk

A method of making a readily dispersible nonfat dry milk by injection of gas into the high-pressure feed line is described and compared with the conventional process for making an instantized powder. The foam spray drying method produces a quickly dispersible product during drying without a subsequent agglomerating step; it permits a greatly increased dryer output, since gas injection improves the efficiency of water removal and makes possible the drying of skimmilk concentrates up to 60% solids; it reduces costs of instant powder manufacture by requiring only minor equipment changes which do not affect the efficiency of the dryer to produce standard type powder. The one-step foam spray dried particle differs from the two-step agglomerated particle, in that it contains gas vacuoles in its structure which, on reliquefying, cause the particle to float before it rapidly dissolves, and more foam to form on the milk surface.