Characterization of monomeric and oligomeric flavan-3-ols from barley and malt by liquid chromatography–ultraviolet detection–electrospray ionization mass spectrometry

The pattern of the monomeric and oligomeric flavan-3-ols for 10 barley varieties and the corresponding malts were identified and quantified using high-performance liquid chromatography–ultraviolet detection–electrospray ion trap mass spectrometry. The Folin–Ciocalteau and the vanillin spectrophotometric assays were used for the assessment of the total polyphenol and total flavan-3-ol content, respectively, and the antioxidant activity was determined as the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and the ferricyanide reducing power. Catechin and prodelphinidin B3 were respectively the major monomeric and dimeric flavan-3-ols. Moreover, prodelphinidin B3 was shown to be the main contributor for the radical scavenging activity both for barley and malt.