Impact of the drying rate on product properties of spray dried emulsions to enable a targeted product design

Spray drying of emulsions is a widespread encapsulation technique to produce a large var-
iety of powdered formulations. The oil droplet size (ODS) in the powder is critical for prod-
uct quality, influencing key product parameters such as the encapsulation efficiency (EE) of
the oil. To expand the understanding of changes in ODS and structure formation during the
drying step. For this purpose, model oil-in-water emulsions were spray-dried at varying air
inlet and outlet temperatures. The powders were characterized regarding ODS and EE.
Smaller ODS were observed for parameter combinations where higher drying rates are
expected due to decreased coalescence. The results for the EE revealed no clear trend. An
increase of air outlet temperature first led to a small decrease in EE followed by a distinct
increase of EE. The first decrease may indicate a collapse of the particle morphology but
more detailed investigations are necessary to explore these phenomena.