Preparation and physical/chemical modification of galactomannan film for food packaging

Abstract

The physical (UV irradiation) and chemical (glutaraldehyde) modification of galactomannan (GMP) film was successfully prepared in this study. The data indicated that the UV irradiation with increasing dosage of photo-initiator could gradually consume the free hydroxyl groups in GMP to form the crosslinked networks, reducing the hydrophilic property and water vapor permeability of the modified film. The tensile strength of the obtained film with 20% sodium benzoate addition achieved 2.8 times higher than the control sample. In comparison, aldol reaction between hydroxyl groups in GMP and glutaraldehyde resulted in a homogeneous surface of films, and the introduction of glutaraldehyde significantly increased the hydrophilicity of the modified films. After chemical treatment, the value of elongation at break was remarkably enhanced by nearly 15 times, corresponding to the great flexible property against stretching.

Keywords: Film; Galactomannan; Mechanical properties; Thermal stability; WVP.