Impact of Buriti Oil Incorporation on the Structural and Functional Properties of Polymeric Films Based on Pectin and Sunflower Seed Protein

The demand for sustainable packaging has driven research into biopolymers as an alternative to conventional plastics. This study developed and characterized biodegradable films based on citrus pectin and sunflower seed protein (SSP), both in isolation and in blends, and investigated the use of buriti oil as a partial or total substitute for the plasticizer glycerol. The films were developed using a casting method and subjected to physicochemical, structural, optical, barrier, mechanical, and biodegradability analyses. The results indicated that the incorporation of the oil reduced moisture content and water solubility, especially in protein-rich formulations. Regarding barrier properties, the buriti oil emulsion maintained similar water vapor and oxygen resistance across most films, with improvements limited to pectin-based formulations for water vapor and to blended formulations for oxygen barrier. However, the complete replacement of glycerol compromised the mechanical properties, resulting in more brittle and less flexible materials, suggesting that the oil emulsion on its own does not act as an efficient plasticizer. The presence of the oil also controlled the rate of biodegradation, prolonging the decomposition time; however, it did not exceed 30 days. It was concluded that buriti oil is a promising functional additive for enhancing MC, WS and thermal stability; nonetheless, its application requires optimization, such as the use of plasticizer blends, to balance the structural stability and flexibility of the films.