University of Salerno, Fisciano, Italy
This research aimed at investigating the potential of olive-pomace extract (OPE) to develop innovative, antioxidant packaging to increase the shelf-life of O2-sensitive products. The active extract was subjected to characterization (dry matter, total polyphenols, hydroxytyrosol content, antioxidant and O2-scavenging capacity) providing basic knowledge for tailor-made packaging design. A second-order mathematical model was applied to describe the polyphenols oxidation-kinetics, and the model parameters were determined.
Active bio-coatings were realized by adding OPE (up to 20% w/w) to a whey-protein-isolate solution, spread on a PET substrate. Multilayer films were characterized by several techniques (FT-IR, DSC, TGA, UV-Vis, contact-angle, photo-oxidative stability, O2/H2O permeability, DPPH and O2-absorption), in order to evaluate their antioxidant efficacy and OPE interaction with the functional performance of the films.
Results highlighted that the scavenging reaction is trigged by humidity and enhanced by the addition of a base, and can be described using the modeling approach, with good agreement between experimental data and simulation results. Active coatings did not substantially modify the chemical and physical properties of multilayer systems, while they showed their potential as oxygen-scavengers and carriers for controlled release of antioxidants.
Outcomes suggest that the formulated bio-films could be considered an effective active packaging solution to protect foods from oxygen-induced quality loss, endorsing this route as a promising for the recovery of high-value compounds applied to competitive commercial solutions.