Interaction of (+)-catechin, (?)-epicatechin, procyanidin B2 and procyanidin C1 with pooled human salivain vitro

Pooled human saliva was mixed with solutions containing either (+)-catechin, (−)-epicatechin, procyanidin B2 or procyanidin C1 at two ratios of admixture and allowed to react at pH 3.2. Precipitates were removed by centrifugation and the supernatants were analysed for the content of proteins and flavanols remaining. The protein determination was unexpectedly difficult and limited the amount of data obtained. The extent to which particular proteins were precipitated (as judged by reversed phase HPLC) did not correlate with the reported sensory potency of these flavanols. The quantity of flavanols precipitated not only did not agree with the relative astringency recorded in the literature, but was in fact the reverse. However, statistical analysis of the data suggested that the quantity of flavanols remaining in the supernatant might be more closely related to their previously determined astringency than to the amount precipitated. More extensive studies, both sensory and analytical, with a greater number of purified flavanols and a superior method of protein determination are required in order to confirm and refine the relationships suggested.