Development of a Sword Bean (Canavalia gladiata) Starch Film Containing Goji Berry Extract

Development of environment-friendly films using natural biopolymers such as carbohydrates has increased because of environmental problems caused by synthetic plastics. This study examined the physical and antioxidative properties of biodegradable films from sword bean starch (SBS) containing goji berry extract (GBE) to develop a novel antioxidant film. As the GBE concentration increased, the tensile strength of the SBS films decreased from 26.32 to 12.42 MPa; however, the elongation at break increased from 7.39 to 12.36%. Although water barrier properties and thermal stability of SBS films were not enhanced by the addition of GBE, ultraviolet/visible light barrier and antioxidant properties were remarkably improved due to its bioactive compounds, specifically zeaxanthin and various polyphenols. In particular, 2,2-diphenyl-1-picrylhydrazyl and 2,2 '-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities of the SBS film with 1.0% GBE were the highest among the films, which were consistent with the total phenolic content results. Therefore, the developed SBS films with GBE are applicable as new antioxidant films in the food packaging industry.