Soy protein-based films incorporated with co-encapsulated cinnamon and paprika oleoresins

Considering growing food demand and waste concerns, sustainable packaging solutions have been explored. Biomacromolecules, like proteins and lipids, offer promising alternatives to conventional polymers for food packaging components. This study investigates the use of oleoresins to enhance the functionality of soy protein isolate (SPI) films. Physical-mechanical properties and antifungal activity against Penicillium paneum were assessed. Cinnamon and paprika oleoresins were incorporated in both free and encapsulated forms (using solid lipid microparticles, SLMs), resulting in orange-colored films. Films containing SLMs exhibited reduced light transmittance (over 50%), potentially protecting photosensitive products from light degradation. Key film properties like moisture content, solubility in water, and water vapor permeability remained unchanged. The thermal curves between 20 and 100 ºC showed no glass transition events. While tensile strength decreased (from 4.83 MPa to 1.80 MPa), the presence of both SLMs and free oleoresins significantly delayed the growth of P. paneum, suggesting potential antifungal activity. The films offer combined barrier and antimicrobial properties, making them a promising sustainable alternative for food preservation. Further optimization efforts could focus on balancing mechanical properties with desired functionalities for real-world applications.