The mouth-feel properties of grape and apple proanthocyanidins in a wine-like medium

A range of structurally defined apple and grape proanthocyanidins was isolated in sufficient amount to carry out a formal sensory descriptive analysis study. Purified proanthocyanidin fractions differed in chain length, degree of galloylation and epigallocatechin content. Astringency attributes of the preparations in a model wine medium were rated while the fractions were held in the mouth and after expectoration. The degree of polymerization appeared to be the variable that discriminated among the fractions to the greatest extent. It affected both the overall astringency and the different individual astringency attributes, with increased 'drying', 'chalky', 'adhesive' and 'pucker' characters correlating with increasing chain length. A rougher sensation with increased 'coarseness', 'drying' and 'chalkiness' correlated with an increased degree of galloylation of the fractions. The presence of epigallocatechin units in the proanthocyanidin tended to lower the 'coarse' perception. (C) 2003 Society of Chemical Industry.