Degree of galloylation

The B- and A-type procyanidins and proanthocyanidins (condensed or nonhydrolyzable tannins, Fig. 6.4) are polymers of flavan-3-ols present in the skin and seeds of the grape berry. In winemaking, they are transferred to the wine, and the sensorial characteristics of astringency and bitterness of wine are linked to the galloylation degree (DG) and degree of polymerization (PD) of flavan-3-ols (Cheynier and Rigaud, 1986 Vidal et al., 2003). 

MW of the terminal catechin unit, c degree of polymerization, g number of galloyl ester, 23 Na atomic mass (Krueger et al., 2000). 

Tannin-protein interactions depend on the characteristics of the tannins size, structure, charge, etc. These interactions increase with the degree of polymerization of the procyanidins (Asano et al., 1984 Ricardo da Silva et al., 1991 Cheynier et al., 1992) and also according to their galloylation... 

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