RESUMO
This study was performed to develop and characterize a bio-film composed of Aloe vera (Aloe barbadensis), green banana Saba (Musa acuminata x balbisiana), and curcumin for the detection of Fe2+ ions. Cross-linking interaction between banana starch-aloe vera gel and banana starch-curcumin enhanced l the sensing performance of the composite film towards divalent metal ions of Fe2+. The morphological structure of the Aloe vera-banana starch-curcumin composite revealed a smooth and compact surface without cracks and some heterogeneity when observed under Scanning Electron Microscopy (SEM). The thickness, density, color property, opacity, biodegradation, moisture content, water-solubility, water absorption, swelling degree, and water vapor permeability of bio-films were measured. The incorporation of aloe vera gel and curcumin particles onto the banana starch film has successfully improved the film properties. The formation of the curcumin-ferrum (II) complex has triggered the film to transform color from yellow to greenish-brown after interaction with Fe2+ ions that exhibit an accuracy of 101.11% within a swift reaction time. Good linearity (R2 = 0.9845) of response on colorimetric analysis was also obtained in Fe2+ ions concentration that ranges from 0 to 100 ppm, with a limit of detection and quantification found at 27.84 ppm and 92.81 ppm, respectively. In this context, the film was highly selective towards Fe2+ ions because no changes of color occur through naked eye observation when films interact with other metal ions, including Fe3+, Pb2+, Ni2+, Cd2+, and Cu2+. Thus, these findings encourage curcumin-based starch films as sensing materials to detect Fe2+ ions in the field of food and agriculture.
