Assessment of chitosan/pectin-rich vegetable waste composites for the active packaging of dry foods

In line with the growing demand for green alternatives to conventional petroleum-derived plastic packaging, fully bio-based and biodegradable biocomposites were developed for this work, for the purpose of packaging dry foods, following the principles of circular economy. Solutions of plasticized chitosan (pCS) were blended with varying amounts of hydrolyzed orange peel (hOP) waste to produce films by casting. The hydrolytic pretreatment of orange peels enabled the creation of biocomposites containing up to 80 wt% hOP, while the formulation with 70 wt% hOP had the best general performance. Chemical characterization of the developed films revealed that chitosan molecules interact electrostatically with pectin molecules in hOP. The strong interaction between chitosan and pectin molecules results in improved mechanical, barrier, and thermal properties of the composite materials compared to their individual components. In addition, the biocomposites exhibit improved water resistance due to their reduced water solubility compared to chitosan and hOP films. The migration of the films' components in the food simulant Tenax was evaluated, and the results revealed low values, compliant with the current EU regulation. However, due to the electrostatic interactions, the films lost the antimicrobial activity of the individual components, chitosan and hOP, against E. coli and S. aureus bacteria, a property that could turn the developed films into active packaging. Finally, the optical and antioxidant properties and the biodegradability in soil of the developed films were also assayed, showing high transparency, antioxidant capacity, and fast biodegradability, reaching 62.9% weight loss after 26 days of the experiment.