The Effect of Selected Phenolic Acids on the Functional Properties of Pectin-Based Packaging Films

In this study, pectin packaging films were enhanced with selected phenolic acids, including caffeic, coumaric, ferulic, gallic, protocatechuic, and sinapic acids. Edible films were created from apple pectin aqueous solutions that were plasticised with glycerol. The evaluation covered various properties, including optical, barrier, mechanical, thermal, structural, and antioxidant activity. The findings showed that phenolic acids are beneficial and compatible components for pectin films. A higher barrier against UV-VIS light and mechanical strength, as well as a more resilient structure, was observed. All the films exhibited a compact and uniform structure, along with transparency and a light colour. The addition of phenolic acids caused greater permeability to oxygen and carbon. Except for caffeic and protocatechuic acids, which resulted in lower values of permeability for both gases, the other acids improved gas transmission. Fourier transform infrared spectroscopy (FT-IR) analysis confirmed several functional groups, including hydroxyl (−OH) and carbonyl (C=O) groups. All films containing phenolic acids demonstrated increased antioxidant activity, with variations depending on the specific compound.