A pectocellulosic bioplastic from fruit processing waste: robust, biodegradable, and recyclable

Recyclable and biodegradable bioplastics made from biomass resources are urgently needed to combat the massive amount plastic packaging waste generated by the food sector. Herein, a novel “top-down” strategy is demonstrated for obtaining high-performance pectocellulosic bioplastics from fruit processing waste, specifically citrus peels rich in pectin and cellulose. The pectin, cellulose and lignin in citrus peels were separated, then the pectin and cellulose components recombined to form a pectin-cellulose film-forming slurry for casting into films. After the cast films had dried, they were then immersed in a CaCl2 solution to crosslink the pectin chains. The obtained pectocellulosic bioplastic films possessed a dense lamellae structure due to inter/intra-molecular entanglement between the cross-liked pectin and cellulose micro/nanofibers, offering excellent mechanical properties, easy recycling and rapid biodegradation. Additionally, this pectocellulosic bioplastic exhibited excellent water stability, water vapor barrier properties, and antioxidant activity. Importantly, the same protocol was applicable for the manufacture of bioplastics from other pectin- and cellulose-rich biomass raw materials (such as watermelon rind, pineapple rind and cantaloupe rind). From both an ecological and economic viewpoint, this biomass-derived bioplastics synthesized in this work offer potential as substitutes for petrochemical-derived plastics in many fields, especially active food packaging.