Impact of starch nanocrystals on the physicochemical, thermal and structural characteristics of starch-based films

The incorporation of starch nanocrystals (SNCs) in starch films can be a way of increasing their applicability. Therefore, the objective of this study was to develop SNCs from rice and potato starch and apply them in films of native rice starch and hydrolyzed rice starch in order to observe the effect of these nanomaterials on the films' properties. The SNCs were produced by hydrolysis for 5 and 7 days and characterized. The films were produced by the casting technique and the SNCs were added at concentrations of 0.1% and 0.3%. The films were characterized in terms of physicochemical, thermal and structural properties. The SNCs showed solubility above 70% while the control starches had solubility around 20%. The addition of SNCs increased the crystallinity of all films produced. The addition of 0.1% rice SNCs to native starch films reduced water vapor permeability by 64% compared to the control. The incorporation of 0.1% potato SNCs reduced the solubility to 14%. The application of 0.3% rice SNCs and 0.1% potato SNCs in native starch and hydrolyzed starch films reduced the surface roughness and fracture, making these films more cohesive. Therefore, SNCs act as a structural reinforcing agent, improving several properties of the films.