Citrus byproduct valorization: pectin extraction, characterization, and research advances in biomaterial derivation for applications in active film packaging

Biopolymers which are biocompatible, biodegradable, and non-toxic, have found noble applications in food packaging films in response to environmental distress and the increased demand for food safety. Pectin, a biomass-based on polysaccharides, is a promising substrate for creating polymeric films. This versatile polymer can originate from various sources like apples, citrus fruits, and more. However, citrus waste emerges as an excellent option for pectin extraction, utilizing a green extraction method, given that citrus generates substantial waste in peel, pomace, and seeds. The environmental, health, and economic concerns associated with citrus waste underscore its potential as a valuable resource. Due to its benefits in terms of film-forming ability, affordability, bioactivity, and compatibility with other polymers that have a unique ability to block oxygen, all of which contribute to extending the shelf life of goods. Adding active agents to packaging films aims to increase the shelf life, maintain the food's sensory quality, and ensure that it is safe and free of contaminants. Natural bio-active chemicals that are embedded into films to avoid microbial deterioration are thought to be promising. These agents can be antimicrobial or secondary metabolites produced by plants and fungi. Active packaging films containing natural additives, including free fatty acids, phenolic compounds, nanoparticles, and essential oils—all of which inhibit or delay the growth of common foodborne pathogens—have extensively used pectin. The functionalization above of pectin films with bioactive substances improved the film's resistance to microbes while simultaneously changing its mechanical strength and barrier qualities. This review thoroughly summarizes using citrus fruit processing waste for pectin extraction, aiming to develop biodegradable packaging films applicable to the food industry. Such initiatives address environmental concerns and foster sustainable food packaging practices.