EVALUATION OF BITTERNESS AND ASTRINGENCY OF (-CATECHIN AND (-)-EPICATECHIN IN RED WINE AND IN MODEL SOLUTION())

Two stereoisomeric phenolic compounds, (+)-catechin and (-)-epicatechi n, were rated for perceived intensity of oral astringency and bitterne ss by trained judges using the scalar method. Mouth drying and mouth r oughening were also assessed, since they are often associated with ast ringency. Amounts of 375, 750 and 1500 mg/L of each compound were tast ed in red wine, and in a model system, similar in composition to a dry table wine. Preliminary tests showed that these: concentrations were above the threshold level but within the range found in wine. A contro l sample (model solution or wine without the addition of the above phe nolic compounds) was also evaluated. The results showed that the two c ompounds were both bitter and astringent. The high (-)-epicatechin con centration was significantly more bitter and astringent than the equal concentration of (+)-catechin in the model solution. Mouth drying and roughening ratings showed a similar increasing pattern with the ratin gs of astringency particularly at the higher concentrations. However, these attributes were rated differently from astringency suggesting th at although they contribute to astringency, they are not subsumed by i t.