Strengthening eco-friendly packaging from pectin by filling with poly(ε-caprolactone) nanoparticles and tailoring the degree of methyl-esterification

Abstract

In light of the environmental damage caused by conventional polymers and the challenge of making polysaccharides competitive in food packaging, there is a growing investment in the development of nanoparticles to enhance their physicochemical properties. Further advancing this concept, we have produced poly(ε-caprolactone) nanoparticles (PCLNPs) via solvent displacement and incorporated them into low- and high-methoxyl pectin films by solvent casting. The PCLNPs display a quasi-spherical morphology with a uniform size (ca. 300 nm), exhibiting excellent colloidal stability due to their hydrophobic PCL core and a hydrophilic Tween 80 surface. PCLNPs moderately improved the thermal stability (reaching ca. 250 °C) and preserved the water vapor barrier (<2 g mm k⁻¹ Pa⁻¹ h⁻¹ m⁻²) of pectin-based films, while providing significant flexibility and achieving a 3.5-fold increase in tensile strength (75 MPa) compared to neat pectin films due to favorable matrix/filler compatibility. Therefore, our findings contribute to the avenue paved for nanocomposites based on polysaccharides to serve as alternatives to nonbiodegradable and/or nonrenewable packaging, reducing environmental impact.