Xanthohumol was identified as a minor yellow pigment from dark beer

Abstract

The colors of pale and dark beers mainly arise from melanoidins, which are formed through the Maillard reaction. However, the melanoidins resulting from this reaction are complex and heterogeneous polymers. To enhance our understanding of the chemical aspects of beer color, we screened for low-molecular-weight yellow pigments using HPLC with photo-diode-array detection. In this study, we isolated a yellow pigment from the neutral or lipophilic fraction of dark beer. This pigment was identified as xanthohumol through instrumental analyses. Xanthohumol, a component of hop resin, was found in dark beer at concentrations ranging from 0.07 to 0.47 μg/mL, while pale beer contained only trace amounts. Using the color dilution method, we visually determined that xanthohumol contributed less than 0.1 % to the overall color of dark beer.