Multifunctional roles of ascorbic acid in biopolymer food packaging: From performance tuning to shelf life extension: A review.

Petroleum-based plastic packaging poses risks to food safety and the environment, driving the shift to biodegradable biopolymers-yet their poor mechanical/barrier properties limit application. Ascorbic acid (AA), a natural, safe, and low-cost additive, emerges as a multifunctional solution for biopolymer-based food packaging. This review summarizes AA's roles: as an antioxidant to inhibit lipid oxidation and browning; a cross-linker/plasticizer to enhance film mechanical strength and flexibility; an oxygen scavenger to reduce food oxidation; and a reducing agent for green nanoparticle synthesis. Encapsulation (e.g., microcapsules, cyclodextrin inclusion) improves AA stability and enables controlled release. The functionalisation of films and coatings with AA has been demonstrated to enhance the overall performance of biopolymer-based materials, including a reduction in water vapor permeability and an enhancement in mechanical properties. Furthermore, such systems demonstrate considerable potential for application in various food preservation contexts; for example, they can delay the spoilage process in fruits and vegetables, inhibit the accumulation of volatile basic nitrogen in meat products, and slow down lipid oxidation in nut-based foods, thereby effectively extending their shelf life. Challenges include AA's sensitivity to heat/oxygen, which requires optimized delivery systems. AA bridges biopolymer performance gaps and aligns with sustainable packaging goals, offering industrial potential for eco-friendly food packaging.