The bitterness and astringency of defined procyanidin fractions from bittersweet English ciders were assessed using a paired-comparison tasting technique. The results demonstrate that, while no one procyanidin can be uniquely identified with bitterness or astringency, bitterness is associated with oligomeric procyanidins reaching a maximum with the epicatechin tetramer whereas astringency is characteristic of higher-molecular-weight procyanidins. The effect of presentation media on taste response was also studied. High sugar and buffer strength suppressed the perceived bitterness, whereas ethanol increased bitterness but simultaneously decreased astringency. It is shown that the observed taste differences between two bittersweet ciders and the taste-modifying effect of ethanol can be explained satisfactorily by current theories of taste.

An isolation procedure was developed for the recovery of the cinnamate derivatives from Miiller-Thurgau white wine by means of adsorption on charcoal, elution with acidic methanol and repeated chromatography on Sephadex LH-20 with dilute acetic acid as the eluent. The crystalline products recovered were cis-and trans-p-coumaroyl-(+ )-tartaric (coutaric) acid and trans-caffeoyl-( +)-tartaric (caftaric) acid, as shown by spectral data, hydrolysis, chromatography, etc. The corresponding quinates were not detected and neither were ferulic acid derivatives nor the free cinnamic acids in this young white wine. The data are briefly discussed in relation to previous reports on these compounds in grapes or wines and their significance as wine constituents.

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The dimeric procyanidins, B2, B1 and B5, and two procyanidin trimers based on (-)-epicatechin were isolated from cider by column chromatography on Sephadex LH20 and counter-current distribution between ethyl acetate and water. The concentrations of these and the other phenolic components in some experimental ciders were estimated by chromatographic separation on columns of Sephadex LH20 employing gradient elution from 20 to 100% methanol. Oxidation occurring during juice extraction markedly lowered the level of the polymeric procyanidins with consequent reduction in bitterness and astringency.