SUSTAINABLE CASEINATE–GUAR GUM FILMS ENRICHED WITH TOMATO BY-PRODUCT OLEORESINS FOR ACTIVE FOOD PACKAGING APPLICATIONS

The development of sustainable and functional biopolymer films is of increasing interest for food packaging applications. In this study, tomato by-product oleoresins (TBO) were used to partially replace beeswax (BW) in sodium caseinate–guar gum (SC–GG) films cross-linked with microbial transglutaminase.TBO incorporation significantly modified the structure of film-forming emulsions, leading to narrower particle size distributions, increased viscosity, and improved physical stability at intermediate BW:TBO ratios. These changes were reflected in the resulting films, where TBO enhanced thermal stability and surface hydrophobicity, while reducing mechanical strength and increasing water solubility.FT-IR analysis confirmed good compatibility between TBO and the SC–GG matrix, highlighting the role of lipid–polymer interactions. In addition, TBO conferred antioxidant activity, which increased with its concentration.Overall, the results demonstrate that tomato oleoresins can be effectively used to develop functional and antioxidant films, showing potential for application as sustainable active materials in food packaging.