Evaluation of Physical, Mechanical and Antimicrobial Properties of Pullulan Films Enriched with Free and Encapsulated Tragopogon graminifolius DC. Extract for Use in Food Packaging

In this study, the effect of adding the extract of Tragopogon graminifolius DC. in the free forms and Encapsulated to the biodegradable film of Pullulan polysaccharide was investigated. For this purpose, the extract of the Tragopogon graminifolius DC. was extracted using ultrasound method and the amounts of phenolic compounds, antioxidant properties (free radical scavenging DPPH) and antimicrobial (against gram-negative bacteria such as Escherichia coli and gram-positive Staphylococcus aureus) extract was measured. According to the results, the amount of phenolic compounds was 89.04± 2.18 mg/ g gallic acid and this extract had high antioxidant, So that at a concentration of 1000 ppm extract, the amount of free radical activity of DPPH was equal to 87.86%. The extract had high antimicrobial properties against both bacteria and Staphylococcus aureus was more sensitive to the extract than Escherichia coli. Maltodextrinwhey protein concentrate (1w: 1w) was used for Encapsulated of the extract. The particle size and the encapsulation efficiency were equal to 92.88± 0.97 nm and 61.15± 0.22 %. Then different concentrations of extract and nano-extract of Tragopogon graminifolius DC. (750 and 1000 ppm) were added to Pullulan polysaccharide film and the properties of the produced films were studied. The results of the present study showed that the moisture, solubility, permeability of water vaporand and transparency in these films decreased and Thickness, resistance to stretch and the maximum tension increased before the rupture point. Also, the replacement of extract with nano-extract in most cases improved the properties of the film. Pullulan polysaccharide film contained an extract with high antimicrobial properties against pathogenic bacteria, which also increased its antimicrobial properties by increasing the concentration and converting the extract to nano-extract. In general, it seems that the antimicrobial film of Pullulan polysaccharide with nano-extract of Tragopogon graminifolius DC. has a high ability as a preservative in food packaging.