Effect of plasticizer type on the mechanical behavior and microstructure of edible peanut protein films

The use of three different plasticizers sorbitol, glycerol, and polyethylene glycol were investigated in the production of edible peanut protein films. Eight films of each plasticizer type were prepared with plasticizer to protein ratios of 2:5 (28.6%), 3:5 (37.5%), 4:5 (44.5%), and 5:5 (50%). The effect of plasticizer content on the mechanical properties was studied. Sorbitol-plasticized films exhibited maximum strength and modules at 44.5% plasticizer content. For glycerol-plasticized films, with the increase of plasticizer content, both the elastic modulus and the strength of the films decreased. Polyethylene glycol-plas-ticized edible peanut protein films were not evaluated mechanically because they were too brittle to be tested. Correlation between the mechanical properties and the morphological features of these films was established. The sorbitol- and glycerol-plasticized films demonstrated promising results towards future food packaging and preservation applications.