Preparation and Characterization of Pea Protein Isolate/Tragacanth Gum Composite Films Incorporating Tea Tree Oil Pickering Emulsions

ABSTRACT This study employed pea protein isolate/tragacanth gum (PPI/TG) as a matrix to fabricate functional packaging films incorporated with tea tree oil Pickering emulsion (TTO‐PE). The effects of varying TTO‐PE concentrations on the films' mechanical properties, microstructure, barrier performance, thermal stability, as well as their antibacterial and antioxidant activities were comprehensively evaluated. The results demonstrated that the composite films exhibited notable mechanical strength (elongation at break up to 108.40% ± 7.28%) and effective UV‐blocking capabilities. Fourier transform infrared and X‐ray diffraction analysis demonstrated strong compatibility among TTO‐PE and the PPI/TG matrix, with no notable alterations detected in the films' amorphous structure. Additionally, microscopic morphological observations confirmed the uniform distribution of the emulsion throughout the matrix, further supporting the excellent interfacial compatibility between the components. Thermogravimetric analysis further revealed that incorporation of TTO‐PE enhanced the films' thermal stability. Moreover, the incorporation of TTO‐PE significantly enhanced the antioxidant activity of the composite films, with the DPPH radical‐scavenging activity increasing from 6.74% ± 0.58% to 41.96% ± 1.23%. The preservation experiment demonstrated that the PPI/TG‐PE 6% composite film effectively maintained the whiteness and visual appearance of Agaricus bisporus , reduced weight loss and loss of firmness and slowed the increases in total soluble solids content and electrical conductivity during storage, thereby preserving mushroom quality and extending shelf life.