Abstract: In this study, the effect of dynamic high-pressure microfluidization (DHPM) on the contents of catechin, procynidin B2 and epicatechin in grape seed proanthocyanidin extract (GSPE) was studied. The proanthocyanidins were subjected to different cycles (1–4) of DHPM at different pressures (100, 140, 180, 220 and 260 MPa) and then analyzed by high performance liquid chromatography (HPLC). The results showed that the contents of these substances increased with increasing DHPM pressures, but they rose firstly and then declined with increasing number of DHPM cycles. Two DHPM cycles at 260 MPa resulted in the highest contents of catechin and epicatechin (0.163 2 and 0.128 6 mg/mL, respectively) among all treatments and the highest content of procynidin B2 of 0.057 6 mg/mL was obtained after three DHPM cycles. Hence, it was demonstrated that DHPM could destroy the non-covalent bonds between polymeric proanthocyanidin chains and consequently depolymerize them into oligomers and monomers with higher biological activity.

Key words: dynamic high-pressure microfluidization (DHPM), catechic, procynidin B2, epicatechic, high performance liquid chromatography chromatography (HPLC)