Unplasticized kefiran films were the smoothest and accordingly have
the lowest values of roughness parameters. The lactobacilli inclusion
did not increase the roughness whereas the presence of yeast in the
films did. When glycerol was included as plasticizer a higher roughness
value was observed in concordance to the observation performed by
Ghasemlou, Khodaiyan, and Oromiehie (2011). On the other hand, the
inclusion of the mix of bacteria and yeasts to plasticized films did not increase
significantly the roughness parameters (Table 1).
The mechanical characterization of films is presented in Fig. 2.
Kefiran films showed tensile strength ranging between 8.1 MPa and
14.6 MPa (Fig. 2a). The incorporation of microorganisms to