Physicochemical, mechanical, and structural features of oxidized oat and banana starch films enriched with betalains

Starch is an alternative for developing biodegradable films that reduces the problem of environmental pollution generated by synthetic plastics. Safe materials with this characteristics must looked after, with similar properties to those of common plastics and, rather recently, they should have additional functionality. Therefore, the objective of this study was to produce films with oxidized starches of banana and oats with added betalains. The experimental design was completely random with four treatments. A one way ANOVA was carried out and means comparison was assessed with the Tukey statistical test (p≤0.05). The oxidized banana starch films presented higher tensile strenght values (5.7 MPa) and elastic modulus (7.2 MPa), but its percentage of elongation was lower (25 %) compared with the films of oxidized oat starch (1.6 MPa in stress fracture, 0.2 MPa modulus of elasticity, and 127 % elongation). The addition of betalains increased the elongation percentage in the starch films without affecting other mechanical properties, and further increased the permeability to water vapor. The x-rays diffraction showed a possible interaction between the oxidized banana starch and the betalain. Chemical modification by oxidation of the starches conferred physicochemical and functional properties to the films for packaging materials and polymeric matrices use via the incorporation of betalains.