STUDIES ON FROZEN BEER PRECIPITATES I. FORMATION AND GENERAL CHARACTERS

Abstract

When beers were kept frozen at −8° to −10°C. and then thawed at room temperature, white flake-like precipitates were formed in most of the commercial beers tested. The frozen beer precipitates consisted mainly of non-starchy polysaccharides. Quantitative analysis of acid hydrolysates showed that the precipitates contained 83% glucose and 6% pentoses (xylose and arabinose). Using a partially purified preparation, various characters such as susceptibility to hydrolytic enzymes, infra-red absorption spectra, and optical rotation were examined, and the results suggested that the main component of the frozen beer precipitate is a β-linked glucose polymer, β-glucan. Effects of temperature and duration of freezing on the formation of the precipitate were examined, and the mechanism of formation of the frozen beer precipitate is discussed.