Polymerization of phenolic compounds by polyphenol oxidase from bell pepper with increase in their antioxidant capacity

Bell pepper (Capsicum annum) fruits are rich in flavonoids, which have high antioxidant capacity. Polyphenol oxidase (PPO) from bell pepper fruit was partially purified and used to polymerize phenolic compounds. Hydrodynamic diameters of the resulting products were analyzed with dynamic light scattering, and their relation to antioxidant capacity studied. Bell pepper PPO catalyzed polymerization of free phenolic compounds, producing 1500 nm aggregates with antioxidant capacity greater than the corresponding monomers. Polymerization was greatest using epicatechin, forming 5000 nm aggregates with antioxidant capacity higher than the monomer. The aggregates produced from ferulic acid exhibited 15 times more antioxidant capacity than the monomer. Quercetin was the least polymerized, but its aggregates still had antioxidant capacity higher than its monomer.