Microcapsules prepared with different concentrations (Fig. 1a–c) indicate spherical shapes with evidence of indentation and collapse which might be due to the rapid evaporation of moisture during drying.
Microcapsules produced at a concentration of 10% show more evidence of indentions (Fig. 1a) compared to those prepared at higher protein concentrations of 20% and 30% (Fig. 1b and c).
It is important to note that microcapsules produced at lower concentrations (10%) resulted in smaller particles with sizes ranging from 1 to 7.8 lm.
However, spray drying with feed solutions at a higher concentration of 20% (Fig. 1b) gave sizes predominantly between 2 and 14 lm and those for 30% (Fig. 1c) had diameters of up to 23 lm.
The higher concentration of 30% also resulted in the lowest survival rate. One possible reason is the longer drying time required to achieve a desired moisture content of 5.5%.