Bilayer bioactive film based on sage seed gum-pea protein isolate/electrospun zein loaded with cumin essential oil: characterization, biodegradability and release study

Abstract

The novel bilayer film was developed based on a pea protein isolate (PPI)-sage seed gum (SG) and diverse thickness of Zein-cumin essential oil (CEO) electrospinning fibers layer (0, 15, 30, 45, and 60g/m²). Then the mechanical, structural, barrier, thermal properties, biodegradability, and release behavior of the bilayer active films were evaluated. Increasing the thickness of the Zein-CEO nanofibers significantly improved the tensile strength (TS), elastic modulus, barrier properties against oxygen and water, antimicrobial activity, total phenolic content (TPC), and antioxidant properties (p < 0.05). The PPI-SG/Ze6 remarkably prevented the light transmittance by about 300% higher than the PPI-SG1/Ze0. Adding the Zein-CEO electrospinning nanofibers to the composite film significantly increased the surface hydrophobicity (p < 0.05). Moreover, the percentage of the moisture content (MC), water solubility, and swelling ratio in PPI-SG/Ze6 to the PPI-SG/Ze0 obtained 69.23%, 53.68%, and 55.07%, respectively. The FESEM images exhibited the homogenous and compact structure of the bilayer films, especially in bilayer films containing higher thickness of the nanofiber layer. Besides, the FTIR results confirmed the successful interaction between Zein, CEO, PPI, and SG and the X-ray diffractometer revealed the increase of crystallinity degree in the bilayer films containing higher thickness of the Zein-CEO. According to the DSC curves, adding the thickness of nanofibers, increased the thermal stability and melting temperature of bilayer films, and the CEO release profile represented that the bilayer active films can efficiently control the release of the CEO in different simulant, especially in aqueous simulant. All these findings revealed that developed bilayer biodegradable films would have potential applications in the packaging.