Developing renewable polysaccharide-based bioplastic films using pectin derived from agricultural cocoa husk byproducts: fabrication, characterization, and performance assessment

Given the significant environmental concerns raised by the accumulation of petroleum-derived plastics, efforts have focused on developing sustainable alternatives, especially bio-based and biodegradable plastics. The excessive generation of cocoa husks as agricultural byproducts poses environmental and disposal issues, thereby necessitating the exploration of sustainable strategies for their valorization. To address plastic pollution and valorize cocoa husk waste, this study aims to evaluate the feasibility of using cocoa husk pectin (CHP) as a film-forming biopolymer for bioplastic film preparation. The production yield of CHP was determined during pectin extraction, and its physicochemical properties, including functional groups, esterification degree, methoxylation content, and ξ-potential, were characterized. Apart from producing CHP-based bioplastic films by glycerol (Gly) plasticization and casting, the effects of Gly and CHP concentration on the film-forming behavior and chromatic properties of CHP bioplastic films were examined. Furthermore, contact angle and infrared analyses showed that bioplastic films exhibited surface hydrophilicity and extensive hydrogen bonding between CHP and the plasticizer. Regarding optical properties, the CHP bioplastic films with varying CHP and Gly contents exhibited an opacity of ∼31–71 % and resistance to UVC, UVB, and UVA of ∼85–99 %, ∼68–99 %, and ∼57–95 %. The water vapor permeability (WVP) and antioxidant activity of CHP bioplastic films were determined to be ∼5.9–8.0 × 10 −8 g m∙m −2 ∙Pa −1 ∙h −1 and ∼67–88 %. Accordingly, the renewability and soil degradation of CHP-based bioplastic films were assessed. Finally, our investigation provides a nice example of valorizing agricultural cocoa pod husk byproducts into CHP-based bioplastic films.