At the beginning of storage no significant difference among the different wine samples was observed for the flavan-3-ols monomers and oligomers content.
The mDP of the studied wines varied from 4.28 to 5.20, which are in agreement with values reported in the literature for Touriga Nacional, Trincadeira, Castelão, Syrah, and Cabernet Sauvignon wines with mDP varying from 2.1 to 9.6 (Cosme et al., 2009). The 600 MPa wine exhibited a slight higher mDP and %P values than the 500 MPa and unpressurized wines (Table 4). These results allow inferring that pressure treatment of 600 MPa for 20 min increased the polymerization rate of higher molecular weight
proanthocyanidins at the beginning of storage, leading to higher mDP
and %P values without changing the flavan-3-ols monomers and oligomers
content. In addition, pressure treatment of 500 MPa for 5 min did
not affect the polymerization rate of proanthocyanidins at the beginning
of storage. These results are in line with the literature