Synthesis of bioplastic films from Vitex negundo L. leaf extract based on sweet potato starch and investigation of antibacterial activity of the products

Abstract

Plastic pollution and food safety are global challenges requiring sustainable solutions. This study aimed to develop a multifunctional bioplastic film from sweet potato starch combined with Vitex negundo L. leaf extract with antimicrobial properties. Optimization processes determined that 10% (w/w) glycerol plasticizer combined with 10% extract produced films with appropriate physicochemical properties, including tensile strength of 4.26 MPa and low water absorption. FT-IR and SEM analyses confirmed the successful incorporation of the extract into the molecular structure of the film, with a homogeneous surface free of cracks. Notably, the bioplastic film exhibited antimicrobial activity against both Gram-positive (Listeria innocua) and Gram-negative bacteria (Escherichia coli O157:H7, Salmonella enterica) - key foodborne pathogens. Importantly, this antimicrobial activity was maintained after three months of storage, demonstrating the long-term stability of the product. The results of this study reveal extensive potential applications for environmentally friendly food packaging materials capable of extending food preservation time while reducing contamination risks. This bioplastic film not only contributes to providing solutions for plastic pollution but also utilizes locally available agricultural resources for material production, supporting sustainable development goals.