In this article, edible hydrocolloid films were prepared by using Citrus pectins and the protein phaseolin in the presence of microbial transglutaminase, an enzyme able to catalyze isopeptide bonds between endo-protein-reactive glutamine and lysine residues. For the first time, trehalose, a nonreducing homodisaccharide into which two glucose units are linked together by a α-1,1-glycosidic linkage, was used as a component of hydrocolloid films constituted of both proteins and carbohydrates. Our data have demonstrated that these films act as very effective barriers to gases, especially to CO2. They also present a high antioxidant capability as measured by the 2,2-diphenyl-1-picrylhydrazyl scavenging assay. In addition, the films were characterized using Atomic Force Microscopy, a powerful tool used to evaluate film surface topography and roughness. The results of our experiments clearly indicate that the trehalose-containing films prepared both in the presence and absence of transglutaminase are composed of nanoparticles with a smooth surface, having similar roughness values (Rα). In conclusion, according to barrier and antioxidant properties and to their structure, it is possible to consider the trehalose-containing films as innovative bioplastics potentially able to protect different kinds of foods. © 2014 Wiley Periodicals, Inc. Biopolymers 101: 931–937, 2014.