A comparative study of polyphenolic and amino acid profiles of commercial fruit beers

Abstract The individual polyphenols, free amino acid (AA) profiles, and pigments (β-carotene and monomeric anthocyanins) concentration of twenty-nine commercial beers were quantified. Additionally, a physicochemical characterization consisting of density, °Brix, color, and % alcohol content (ABV), was performed. The ABV ranged from 2 to 9 %, °Brix from 2 to 12, and a broad color spectrum, ranging from yellow (4 °SRM) to black (39 °SRM) was observed. Total free amino acids (TAA) content ranged from 49−3,902 mg/L. The concentrations of nineteen quantified polyphenols ranged between 4−298 mg/L, being catechin (38−298 mg/L) and epicatechin (19−354 mg/L) the most abundant compounds, while the pigments content ranged between 4−35 mg/L. The observed differences were mainly attributed to the brewing style as well as the type and amount of added fruit. Principal component analysis (PCA) showed five different groups for polyphenols, pigments, and AA related to their chemical structure. This allowed clustering samples according to the proportion in which each category contributed to the total phenolic + pigments content or TAA. It was noted that “Fruit Lambic” beers were the only brewing style that showed similar trends in the performed analysis.