Valorisation of pomelo peel waste for pectin-based bioplastic films: extraction optimization, film fabrication, and comprehensive characterization

Plasticsmade from petroleum are one of the major causes of environmental problems. This is because they remain in the environment and are a source of microplastic pollution. Biodegradable films made from natural polymers are a better option for the environment. Pomelo peel (Citrus maxima) is a by-product of the citrus industry and is a good source of pectin that can be used for bioplastic. The main goal of this work is to optimize pectin extraction from pomelo peel waste, fabricate pectin–chitosan–sorbitol composite films, and then evaluate physicochemical and structural properties of these films to determine their preliminary feasibility as sustainable packaging. The pectin extraction was performed by using an environmentally friendly method that includes hydrolysis with citric acid and precipitation with ethanol. The composite films were made by solvent casting a solution of pectin, chitosan, sorbitol, and citric acid. The films were tested for moisture content, water solubility, and FTIR functional group analysis. The pectin yield was 20%, which is in line with the literature on citrus peel extraction. The films were flexible, smooth, semi-transparent, and light yellow in colour. The moisture content (8.8%) and water solubility (32%) were good for biodegradable pectin films. FTIR results showed the presence of characteristic pectin and chitosan functional groups, indicating successful polymer interaction and partial cross-linking. Pomelo peel waste is a renewable resource for pectin-based films that are biodegradable. The physicochemical properties of the films point to the possibility of such films being used for short-term sustainable packaging. Testing of mechanical strength, thermal behaviour, and biodegradation is necessary for further confirmation.