Effect of sorbitol and glycerol plasticizers on physical and mechanical properties of rice and potato starch-based films

Abstract

The effectiveness of the polysaccharides and more specifically of rice and potato starch by the using of two plasticizers (sorbitol, glycerol) on the mechanical and physical properties of the films were examined. Edible films from rice and potato starch were prepared and were stored in specific percentage of relative humidity (RH) before being used on the mechanical (elongation at break, tensile strength) and physical (water vapor permeability, moisture uptake) test. The presence of the sorbitol and glycerol did not have a significant effect on tensile properties. More specifically, only at elongation at break (EB) it was observed that films with sorbitol had a stronger structure. On the other inhomogeneity was observed due to the fluctuations in the values of the tensile strength (σ max) from all types of films. In addition, sorbitol proved as a good plasticizer in the water vapor permeability (WVP) (G-MM/H-M2-KPA) where the films shown very low values compared to glycerol films. Concerning to moisture uptake (MU), increasing the % of RH where the films stored, gr of water per 100 gr dry matter also increasing. In this physical property the glycerol plasticized films absorbed more water in all RH levels compared to sorbitol plasticized films.