Beer has been highly appreciated due to its phenolic composition and antioxidant capacity conjugated with its low alcohol content. Although the existence of some studies regarding the phenolic composition and antioxidant capacities of beers, there is no studies related to the determination of these parameters in the most consumed commercial beers in Portugal. The phenolic composition and antioxidant capacity of twenty-three Portuguese commercial beers of different styles and types from, was studied for the first time. The total phenolic content, ortho-diphenols, and flavonoids ranged between 0.15 ± 0.01 and 0.82 ± 0.07g GA /L; 0.07 ± 0.02 and 1.80 ± 0.09 g GA/ L, and 0.02 ± 0.00 and 0.15 ± 0.02 g CAT/L, respectively. An accurate quantitative phenolic analysis was also performed, and the compound identified in higher amount was gallic acid, followed by the syringic acid. Concerning flavonoids, gallocatechin was the most abundant compound identified (from 21.44±2.87 and 144.00±10.93 µg/mL). A significant correlation between ortho-diphenols and the antiradical capacity (ABTS and DPPH) was found, being the latter negatively correlated. Flavonoids content was also positively correlated with total phenols and antiradical capacity determined by the ABTS assay. These results evidence that phenolic composition is affected by several factors inherent to beers, namely ingredients, fermentation type, and brewing process.

Acknowledgments

This work was supported by National Funds by FCT - Portuguese Foundation for Science and Technology, under the project UIDB/04033/2020, and FEDER-Interreg España-Portugal programme for financial support through the project 0377_Iberphenol_6_E.