Influence of Packaging Material on Polyphenol Content and Antioxidant Activity in Some Commercial Beers

Using two methods (ferric reducing antioxidant power and radical scavenging activity), the total polyphenol content (Folin–Ciocalteu reagent) and polyphenol patterns (HPLC) in 10 commercial lager beer brands produced in Romania was determined. Samples bottled in glass, plastic and aluminium packages were analysed for each brand when available. Results have indicated considerable variations in the total and individual phenolic contents as well as antioxidant activity across beer brands. A statistical analysis was performed to assess the influence of packaging type on the antioxidant activity and phenolic content of the beers. Statistical differences were found between the DPPH and FRAP methods in glass, aluminium and plastic material. Moreover, the antioxidant activity based on the DPPH method is influenced by the type of packaging material, while in the case of FRAP method, no statistical difference was reported. Furthermore, the same analysis has shown that the polyphenol concentration is invariant to the type of material.