Characterization of insect chitosan films from Tenebrio molitor and Brachystola magna and its comparison with commercial chitosan of different molecular weights

Insects are considered as alternative sources of chitosan; however, studies about the functional film-forming properties of insect chitosan are scarce. Insect chitosan films were made from Tenebrio molitor and Brachystola magna and were compared with commercial chitosan of different molecular weights (M-w). Mechanical properties (tensile strength, TS; elastic modulus, EM; elongation at break, %E), water vapor permeability (WVP) and physicochemical properties were characterized. The film properties of both commercial and insect chitosan were affected by Mw. Commercial chitosan films showed that at lower M-w, the TS (from 59 to 48 MPa) and EM (from 1471 to 1286 MPa) decreased; whereas WVP (from 2.9 x 10(-11) to 3.4 x 10(-11) g m(-1)s(-1)Pa(-1)), % E (from 38 to 41%) and solubility (from 30 to 33%) increased. Chitosan insect films showed lower TS and EM, and higher WPV, %E and solubility than commercial films. SEM revealed that chitosan insect films had lower porosity than commercial films. FTIR and X-ray diffraction showed not difference between insect and commercial chitosan films. These results showed that T. molitor and B. magna chitosan films could be used as a packaging material in several food products. (C) 2020 Elsevier B.V. All rights reserved.