THE INFLUENCE OF ASSORTMENT OF BEER ON THEIR ANTIOXIDANT / PRO-OXIDANT CAPACITY AND PHENOLIC FINGERPRINT

Different assortments of beers, packed in cans and bottles, exist on the market. Beer has a complex and balanced composition, phenolic compounds being one class of bioactive constituents that are of particular interest due to their essential role in the brewing process, physical stability and aroma of this beverage. The aim of this paper is to integrate antioxidant and pro-oxidant evaluation, total phenolic content (TPC) determination, chromatographic fingerprinting and chemometric methods in order to study the influence of the variety and the packing type for beer assortment recognition. The antioxidant capacity evaluation was done by 2,2-azinobis(3-ethylbenzothiazolyne-6-sulphonic acid) radical cation (ABTS) assay and Folin-Ciocalteu method was used and to determine the TPC. Thin-layer chromatography (TLC) and high performance liquid chromatography (HPLC) were applied to obtain the fingerprints of beers. The results show that antioxidant and pro-oxidant capacities, the TPC and the chromatographic fingerprints were influenced by the packing type, the assortment, the alcoholic content and the colour of beer. Principal component analysis and cluster analysis were applied to study the influence of the variety and bottling type of beers on their characteristics. The results demonstrate that by integrating various methods the classification of beers based on their assortment was enable. Keywords: antioxidant capacity, pro-oxidant capacity, phenolics fingerprint, beer assortment, TLC,HPLC, PCA, cluster analysis