Fabrication of biodegradable and active pectin-based films with enhanced properties by the incorporation of natural eutectic solvents

Abstract

Achieving biodegradable and functional food packaging with enhanced mechanical resistance, barrier efficiency, and bioactive properties remains a challenge. This study investigates the incorporation of natural eutectic solvents (NAES) as a strategy to improve the performance of pectin-based films. These NAES, composed of choline chloride (ChCl) and tannic acid (TA) or citric acid (CA), were added at concentrations of 67 and 80 wt% to develop materials suitable for food packaging applications. The films were fabricated via a casting method, and their structural, physicochemical, and functional characteristics were thoroughly analyzed. Results revealed that NAES played a key role in reinforcing the mechanical properties of the films, increasing their tensile strength from ≈0.75 MPa in the control samples to ≈2.2 MPa. Additionally, the presence of NAES significantly improved the films’ capacity to block UV radiation, particularly in the 200–350 nm range, which is crucial for preserving light-sensitive food products like polyunsaturated oils. Environmental sustainability was also confirmed through biodegradation assays, where the films exhibited an 80% weight loss after 20 days in soil. Furthermore, antimicrobial properties conferred by NAES effectively inhibited the growth of E. coli and S. aureus, with inhibition zones surpassing 15 mm. When applied to food preservation, the films provided remarkable oxidative protection to chia oil, reducing hydroperoxide levels from approximately 57 to 7.5 meqO₂ kg⁻¹ oil, while extending the oxidation induction period from 0.25 to ≈4.6 hours over 25 days of storage in oxidative accelerated conditions. These findings underscore the potential of NAES as active additives that enhance the properties of biopolymer-based films while imparting bioactive functionality, paving the way for sustainable and efficient food packaging solutions.