The appearance of the surface and cross-section of selected films is
presented in Fig. 2 in the form of SEM micrographs. Both the control
pullulan film and SBE-containing pullulan film were characterized by
a smooth surface as well as a uniform and compact internal structure,
without granulations and pores. This proves that SBE components
were evenly spread in cross-linked pullulan, and thus an integral film
structure was formed. Plant extracts including compounds of hydrophilic
character usually fit well to the basal hydrocolloids of the films.
Hoque, Benjakul, and Prodpran (2011) reported that gelatin film with
incorporated star anise extract was characterized by a smooth and
homogenous surface and uniform internal structure, which was additionally
more compact compared to the structure of the film without
the extract. The authors suggested that this is an effect of interaction
occurring between the phenolic compounds of star anise extract and
gelatin molecules