The diagram of the desirability test indicated that the most suitable formulation consisted of 66.5 g 100 g1 DPP, 9.5 g 100 g1 EPP and 24 g 100 g1 AF. Thus, FS6 was considered the most desirable sample because of its ranking on the desirability test, that is, a proportion of 65:10:25 of the components listed above, respectively. Using a scanning electron microscopy, FS6 showed a better surface, which confirmed the results of the desirability test (Fig. 3F).