STUDIES ON BEER HAZE FORMATION. II. DIMERIC FLAVANOIDS OBSERVED IN PROFILES OF BEER: NYLON 66 ADSORBATES

A peak in the gas chromatographic profile of beer: Nylon adsorbates has been found to comprise three unresolved biflavan components. One of these, molecular formula C30H26O12, consists of two C—C linked catechin units and has the same structure as a biflavan obtained by the acid catalysed interaction between cyanidiol and catechin. It appears to be the same as the procyanidin previously isolated from beer. The other components, both with molecular formula C30H26O13, have the same skeletal structure as the first, but are linked catechin-gallocatechin pairs, one being a prodelphinidin, the other a procyanidin. Dicatechin, a tannin obtained by treatment of catechin with dilute mineral acid, also seems likely to be a component of the adsorbate profiles.