The development of biodegradable materials from natural and renewable sources reduces the need of synthesizing petroleum-based polymers, eliminating the negative effects produced on the environment. The aims of this study were to evaluate the physical and chemical effects produced in films by the modification of a material obtained from natural sources, such as isolated soy protein (SPI) and different amounts of Gen, a new natural cross-linker about 10000 times less cytotoxic than glutaraldehyde. Hence, the opacity, cross-linked degree (CL%), total soluble matter (TSM), moisture content (MC), surface and mechanical properties, swelling in water and water vapor permeability (WVP) of the films yielded were investigated to assess the potential of Gen for improving SPI film properties. In addition, biodegradation studies were performed.