Biodegradable TPS/PBAT Blown Films with Ascorbyl Palmitate and Sodium Ascorbyl Phosphate as Antioxidant Packaging

The development of biodegradable active packaging is a relevant topic demanding the development of film properties, biodegradability, and the potential to preserve food quality. This study aimed to develop thermoplastic starch (TPS) blended with polybutylene adipate-co-terephthalate (PBAT) films via blown-film extrusion containing ascorbyl palmitate (AP) and sodium ascorbyl phosphate (SAP) as antioxidants. The morphology, mechanism, and barrier and antioxidant properties of the films were analyzed to determine the presence of AP, SAP, and their interaction effect on the film properties. SEM showed that increasing AP and SAP content increased fibrous-like morphology, improving the TPS dispersion. AP slightly decreased mechanical properties, while SAP increased the tensile properties and seal strength of the films. All of the YM values were increased by adding AP and SAP content. The addition of AP and SAP content enhanced the interaction with TPS/PBAT networks due to increasing C-O stretching of ester bonds, compatibility, and hydrophobicity of the polymer. Both water vapor and the oxygen barrier were insignificantly affected by AP and SAP up to 1%, while the permeabilities greatly increased at higher AP and SAP contents due to non-homogeneous and void spaces between the film matrix. TPS/PBAT containing AP and SAP (≥0.5%) effectively enhanced antioxidant capacity in 95% ethanol as a food simulant and reduced the UV light transmission of the films. Finding, the interaction between AP, SAP, and TPS/PBAT matrices effectively changed the microstructures and properties as functionalized antioxidant biodegradable packaging.