Study of the effect of the addition of plasticizers on the physical properties of biodegradable films based on kefiran for potential application as food packaging

•A branched exopolysaccharide was isolated from kefir by physical extraction.•Kefiran plasticized films were prepared by loading 2 and 5% w/w of plasticizers.•Kefiran solubility decreased with the incorporation of polyols as plasticizers.•The addition of plasticizers improved the thermal stability of the kefiran.•Type and concentration of plasticizer decreased the microhardness of the polymer.