Effect of the concentration of starch and clove essential oil on the physicochemical properties of biodegradable films

Biodegradable films were obtained with the casting method using different concentrations of purple sweetpotato Ipomoea batatas (L.) starch and clove Syzygium aromaticum (L.) essential oil. Mechanical properties (tensile strength, percentage of elongation and Young's modulus), water vapor permeability and film adsorption isotherms were evaluated. In the formulations containing the intermediate concentrations of the components, a homogeneous surface, an improvement in fracture stress and a decrease in water vapor permeability were observed. The statistical analysis showed a significant difference in the mechanical properties of the composite films (p < 0.05). The GAB model was used to adjust the experimental data of the adsorption isotherms and a higher moisture content of the films containing the highest concentration of starch and essential oil was observed. The F6 (starch 3.5%, clove essential oil 60 mg/L) formulation showed the lowest water vapor permeability values (1x10-8 g/ m s Pa) and the lowest moisture content in the monolayer, which is considered to be the material with the best characteristics for its possible application, avoiding the excessive use of raw material during its preparation.