Temperature-induced shape memory behavior of antibacterial against Salmonella typhimurium films made from potato starch and silver nanoparticles

Smart packaging with biodegradable polymers has emerged as a response to food challenges in a modern society, in terms of environmental impact, innovation, quality and safety. For that reason, it is important to design and understand smart materials that may have high potential for application in food science. In this work, films based on potato starch reinforced with six different levels of content of silver nanoparticles (AgNp) were produced by casting with the aim of evaluating its potential use as a material for smart packaging. The films were evaluated in terms of shape memory stimulated by temperature, antibacterial activity (against Salmonella typhimurium) , thermo-mechanical and physicochemical tests. Addition of AgNp in potato starch films modified the assembly of polymer chains, with changes observed in superficial water affinity, thickness, and shape memory. Nanocomposites films showed antibacterial activity against Salmonella typhimurium , and they were efficient at blocking ultraviolet light and extending this protection to visible light, unlike control samples without nanoparticles. AgNp mechanically reinforced potato starch films, showing an increase in the elastic modulus greater than 200%. Furthermore, the film intermediate content of AgNp exhibited higher thermal stability than the control potato starch film, increasing its thermal degradation temperature by 15 °C. Additionally, an enhanced shape memory response of potato starch films is observed at an activation temperature of 80 °C for the formulation with the lowest AgNp content. Therefore, establishing the amounts of AgNp in potato starch allows us to modulate the properties of the nanocomposite, depending on the requirements of smart packaging.