Effects of the addition of ultrasound‐pulsed gelatin to chitosan on physicochemical and antioxidant properties of casting films

This study investigated the performance of chitosan based films with added, high‐intensity ultrasound‐pulsed, gelatins (42, 52, 71 and 84 W cm^?2). The mechanical, structural, chemical and antioxidant properties were investigated, to evaluate the potential of ultrasound as a technique to improve film properties. The tensile strength and elastic modulus of films containing ultrasound‐pulsed gelatins showed a significant increase, while the elongation parameter showed a significant decrease. Micrographs showed that all films presented agglomerations. The infrared spectra of the films displayed characteristic shifts in the chitosan and gelatin spectra, which may be the result of hydrogen bridge interactions and electrostatic interactions between the two polymers. The antioxidant capacity was analyzed through the ferric reducing antioxidant power (FRAP) assay and the 2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulfonic acid) (ABTS) assay of films and showed that gelatins treated with higher acoustic intensity had improved antioxidant capacity. High‐intensity ultrasound‐treated gelatin enhanced the strength, elasticity and antioxidant properties of the chitosan based films. © 2020 Society of Chemical Industry