Arrua, Strumia, and Nazareno (2010) immobilized caffeic
acid on a polypropylene film by covalent binding of
caffeoyl chloride on a modified polymeric surface of PP
films grafted with hydroxyethyl methacrylate as monomer.
The films thus obtained were shown to have available
phenolic groups by the FolineCiocalteu method as well
as antioxidant activity by the DPPH and ABTS assays.
Furthermore, the polymer obtained showed a good protective
activity against ascorbic acid oxidation in orange juice.