Spray Drying in Food Product Development
Spray-drying is the most commonly used encapsulation technique for food products. The spray-drying technique is based on the transformation of a fluid into dry powder by spraying the liquid in a drying gas stream. First, the liquid is sprayed into a drying chamber through a nozzle or atomiser. The small droplets that are generated are subjected to fast solvent evaporation, which leads to the formation of dry particles that are separated from the drying gas by a cyclone that deposes them in a collector. Inclusion of an encapsulant in the solution results in the encapsulation of the active component, the encapsulate. The application of the spray-drying process in microencapsulation involves three basic steps: (i) preparation of the dispersion or emulsion to be processed; (ii) homogenisation of the dispersion; and (iii) spraying of the mass into the drying chamber. By selection of the encapsulant, different properties can be achieved. For example, the solubility of the encapsulant directly determines the behaviour when introduced into an aqueous environment, either releasing the core material or retaining its encapsulated state
.Source: MDPI.com
The spray-drying technique is already widely used in industry because it is simple and relatively inexpensive, it rapidly and continuously produces dry powder (compared to freeze-drying), and the particle size distribution can be controlled. An additional advantage is that this technique is less dependent on the solubility of the additive and the polymer than other methods 24, 32. In addition, this technique can be used as a final step to remove the solvent to produce dry powder from particles in a liquid medium that were synthesised via a different method.
