Plasticization and moisture sensitivity of potato peel-based biopolymer films

This study investigated the effects of the addition of glycerol and high-pressure homogenization on the moisture sensitivity of potato peel-based films (PP films). The films were formed by casting a 3% (w/v) PP suspension containing either a 30 or 50% (w/w, dry basis) glycerol, which was high-pressure homogenized at 69, 138, or 207 MPa with 2, 5, or 10 passes. The elastic modulus and viscosity values were high when the suspensions were treated at 207 MPa with 5 and 10 passes. The moisture sorption isotherms, water diffusivity, and water vapor permeability values were higher in films with 50% glycerol. The findings indicate that high pressures and high pass numbers resulted in anti-plasticization in the film matrix, while the high concentration of glycerol in the film formulation plasticized the film. Thus, the moisture sensitivity of the PP film can be modulated by controlling the homogenization parameters and the glycerol concentration.