Table 1.

Pros and cons of physical and chemical means of antioxidant incorporation.

	Working Principle	Pros	Cons
Physical means	The antioxidant either is entrapped physically by the polymeric matrix or adheres directly to the film	‑Easy to operate ‑Have an extensive track record of use in the literature for film design ‑Ideal to applications in which the protective effect of the film relies on the release of the incorporated antioxidant	‑Safety concern due to the possible migration of the incorporated antioxidant (particularly those whose level in foods is to be tightly regulated) from the packaging material to the food ‑Effective antioxidant incorporation is limited to the antioxidant which is physically compatible with the film ‑Lower stability of the antioxidant-incorporated film for storage
Chemical means	Covalent bonds are adopted to link the antioxidant either to a pre-generated polymeric film or to the monomer before polymerisation	‑Effectively reduce the migration of the incorporated antioxidant from the packaging material to the food product ‑The efficiency of antioxidant incorporation is not influenced by the physical compatibility of the antioxidant with the film ‑Higher stability of the antioxidant-incorporated film for storage	‑Knowledge of synthetic chemistry is required for the design of the material ‑Potentially labour-intensive and time consuming ‑Organic solvents may be adopted during reactions and the chemical residues in the product may cause safety concern ‑Not suitable to be used in situations where the protective effect of the film relies on the release of the incorporated antioxidant