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

Pooled human saliva was mixed with solutions containing either (+)-catechin , (-)-epicatechin, procyanidin B2 or procyanidin C1 at two ratios of admixt ure and allowed to react at pH 3.2. Precipitates were removed by centrifuga tion and the supernatants were analysed for the content of proteins and fla vanols remaining. The protein determination was unexpectedly difficult and limited the amount of data obtained. The extent to which particular protein s were precipitated (as judged by reversed phase HPLC) did not correlate wi th the reported sensory potency of these flavanols. The quantity of flavano ls precipitated not only did not agree with the relative astringency record ed in the literature, but was in fact the reverse. However, statistical ana lysis of the data suggested that the quantity of flavanols remaining in the supernatant might be more closely related to their previously determined a stringency than to the amount precipitated. More extensive studies, both se nsory and analytical, with a greater number of purified flavanols and a sup erior method of protein determination are required in order to confirm and refine the relationships suggested. (C) 2000 Society of Chemical Industry.