Co-encapsulation of anthocyanin and cinnamaldehyde in nanoparticle-filled carrageenan films: Fabrication, characterization, and active packaging applications

Abstract

Nanoparticle-filled films were fabricated as smart and active packaging materials to monitor and preserve the freshness of foods (fish). Antisolvent precipitation was used to produce zein nanoparticles containing anthocyanin in their hydrophobic cores and cinnamaldehyde on their surfaces. These nanoparticles were then coated with a layer of carrageenan, resulting in the formation of anthocyanin-zein-cinnamaldehyde-carrageenan (AZCC) composite nanoparticles. Dynamic light scattering, electrophoresis, infrared spectroscopy, and scanning electron microscopy were used to characterize the properties of these composite nanoparticles. The particles formed were spherical and had relatively small diameters (563 nm) and high negative charges (−24.6 mV). The particles were mainly held together by hydrophobic, hydrogen bonding, and electrostatic interactions. The impact of nanoparticle concentration on the physical, structural, and functional properties of nano-composite films was investigated. Increasing the nanoparticle concentration led to changes in the opacity (17.42 A mm−1), microstructure, thermal stability (65.3%), and antioxidant activity of the films, as evaluated through DPPH (48.39%) and ABTS (92.77%) assays. The changes in color (SLab: 16.98%–85.98%) of the nanoparticle-loaded films was sensitive to pH and ammonia content, which meant that they could be used as quality sensors. The release of anthocyanins from the films depended on the polarity of the model food they were in contact with. Optimized films significantly extended the freshness of Mandarin fish, resulting in a 13.3% reduction in total volatile base-nitrogen levels, which highlights their potential for monitoring and controlling the freshness of packaged foods.