Ternary composite degradable plastics based on Alpinia galanga essential oil Pickering emulsion templates: A potential multifunctional active packaging

Abstract

To reduce the use of petroleum-based plastics and explore multifunctional plastics, this study was conducted to prepare ternary composite plastics by doping Pickering emulsions containing Alpinia galanga essential oil into a polymer network consisting of poly(vinyl alcohol)-acetylated pullulan polysaccharides. Scanning electron microscopy results showed that although incompatible components were present in the composite plastic, compatibility improved with the addition of pullulan polysaccharides, resulting in smooth surfaces and cross-sections, which was consistent with the observation of continuous dark zones and low relative roughness (Ra = 5.51) in Atomic force microscopy. Further, Fourier transform spectroscopy and X-ray diffraction characterization revealed that the composite plastic disrupted the molecular and crystalline structures of the pure PVA, causing the stretching vibration of -OH and the decrease of relative crystallinity. Moreover, this plastic performed optimally at a PVA to pullulan polysaccharide ratio of 75:25, exhibiting good thermal (13.12 J/g) and mechanical properties, low water absorption (70.71 %) and water vapor transmission (1.80 × 10−3 g/m2 s), as well as excellent degradability. In addition, Alpinia galanga essential oil components in the composite plastic provided favorable antioxidant scavenging of DPPH and ABTS and inhibitory effects against Escherichia coli and Staphylococcus aureus. Chicken meat packaging revealed that the plastic maintained sensory parameters such as pH and color by inhibiting the oxidation of proteins and lipids during shelf-life. The findings provide insights into developing innovative, green, multifunctional packaging and broaden the in-depth application of Alpinia galanga essential oil.