Cactus-Based Biopolymers: A Review on Sustainable Innovations in Edible Packaging, UV Protection, Antioxidant Films,...

Cactus mucilage, particularly from Opuntia ficus-indica, has attracted increasing scientific and industrial interest due to its unique physicochemical, structural, and functional properties. It is a heteropolysaccharide matrix enriched with uronic acids and bioactive compounds, providing high water-binding capacity, gelling ability, pseudoplastic flow behavior, and notable film-forming potential. These characteristics make mucilage versatile for applications in food, nutrition, and sustainable materials, although its performance remains sensitive to pH, temperature, and ionic strength. In food science and human health, cactus mucilage demonstrates safety and bioactivity. Clinical and preclinical evidence support the tolerability of daily intakes of up to 5 g of dehydrated nopal powder, while traditional diets indicate even higher safe levels. Functionally, mucilage contributes to food preservation by enhancing barriers against moisture, oxygen, and microbial contamination. Mucilage-based films prolong shelf life through UV-blocking and antimicrobial effects, and their functionality can be further enhanced by incorporating antioxidants, probiotics, or other natural additives. Beyond food, cactus mucilage shows promise as a biodegradable substitute for petroleum-based plastics, aligning with sustainability initiatives. Its film-forming, UV-blocking, and antioxidant properties support the development of active packaging systems, while blending with other biopolymers improves strength and flexibility. Broader industrial applications include water purification through heavy metal removal, oil spill remediation, and enhancing durability and corrosion resistance in construction materials. Despite this potential, commercialization faces challenges including compositional variability, lack of standardized extraction methods, optimization of mechanical performance, and issues of scalability. In regions such as Ethiopia, valorization of cactus mucilage offers an opportunity to reduce plastic dependence, foster local industries, and create new economic opportunities. Globally, cactus-based biopolymers contribute to Sustainable Development Goals on responsible consumption (SDG 12), climate action (SDG 13), and health (SDG 3). Continued research on safety, standardization, and cost-effective production will be vital to fully realize its potential.