Elucidation of Chemical Structures of Components Responsible for Beer Aftertaste

Astringent substances were isolated from malt acrospires. The water extract was fractionated by preparative HPLC. The astringent fraction, which contained three components, was purified by HPLC and identified by MS and NMR spectrometry. The components, in order of decreasing concentration, were 4′-O-β-d-glucopyranosyl hordatine A, 4′-O-β-d-glucopyranosyl hordatine B, and 4′-O-β-d-maltosyl hordatine A. These compounds have not been identified previously, and all exhibited astringent properties.