Characterization of bioactive compounds and antioxidant capacity of Portuguese craft beers

Abstract

Despite the concept of craft beer was introduced in the beer industry recently, it has been growing very quickly. Although there is no exact definition; in fact, a beer is considered a craft beer when it is produced using traditional practices and using traditional or innovative raw materials, and generally it does not undergo filtration or pasteurization.24 Portuguese craft beers from different brands, produced with different raw materials and through different types of fermentation, sold in national super and hypermarkets were analyzed trough their phenolic composition and antioxidant capacity.The results showed that there are relevant differences in the content of phenolic compounds and antioxidant capacity of the analyzed beers. The results of total phenolic content ranged from 0.303 ± 0.006 to 1.614 ± 0.280 g GA/L, the ortho-diphenols values ranged between 0.106 ± 0.004 and 2.216 ± 0.040 g GA/L, and the flavonoids content ranged from 0.054 ± 0.000 to 0.750 ± 0.000 g CAT/L. Concerning the antioxidant capacity, the results ranged from 1.142 ± 0.025 and 10.913 ± 0.305 mmol Trolox/L, and from 0.850 ± 0.052 to 12.109 ± 0.126 mmol Trolox/L, for ABTS•+ and DPPH• methodology, respectively. Regarding the quantification of phenolic compounds by HPLC, the compounds present in almost all the beers and at high concentrations were gallic acid and catechin, with concentrations ranging from 4.20 ± 0.43 to 61.57 ± 0.59 μg/mL and 7.50 ± 0.28 to 147.99 ± 3.83 μg/mL, respectively. The statistical analysis performed by a Principal Component Analysis and Pearson correlation allowed to explain the variance of the beer samples.