Identification and quantification of bioactive compounds of brewery co-product, brewer's spent grain, and determination of antioxidant capacity

Abstract

The solid residues in the beer manufacturing process are generated, mainly in the wort filtration stage, composed by remains of the peel and pulp of the grains, mixed, suspended or dissolved in the wort. Once most of phenolic compounds of the barley grain are in the peel, brewer's spent grain is then considered to be a potentially valuable source of phenolic compounds. These confer important antioxidant properties to the body, preventing some pathologies that involve the participation of free radicals. In this work we evaluated the content of phenolic compounds from brewer's spent grain by ultraviolet / visible spectrometry and the characterization of these compounds by high performance liquid chromatography (HPLC). The total phenol content in this extract was 1.06 ± 0.54 mg EAG / g extract and 0.24 ± 0.07 mg EQ / g extract for flavonoids. HPLC analysis revealed the presence of gallic acid (2.43 ± 0.04 mg / extract) and p-coumaric acid (0.16 ± 0.01 mg / g extract), known antioxidant compounds. The extract showed antioxidant activity of 23.17 mg/mL, that indicates the presence of constituents capable of capturing free radicals, as indicated by the HPLC analysis, characterizing this subproduct as a potential source of bioactive compounds.