Acid mediated hydrolysis of blueberry anthocyanins

Acid mediated hydrolysis of anthocyanins was studied using capillary zone e lectrophoresis (CZE), A commercially available wild blueberry (Bilberry) ex tract was dissolved in different concentrations of TFA (0.1, 1, 3, 9%), the n was subjected to thermodecomposition reaction at 95 degreesC. After the r eaction, the samples were analyzed by CZE, The hydrolysis rate of each anth ocyanin and the formation of the aglycon were determined by the change in t he peak pattern of the anthocyanins in the electropherogram. Each anthocyan in peak decreased time dependently in a first order kinetic fashion. It was revealed that the hydrolysis rate of each anthocyanin was determined prima rily by the type of conjugated sugar and not by the aglycon structure. The rate constant of anthocyanin hydrolysis was in the following order, arabino side>galactoside>glucoside without regard to the aglycon structure. The kin etic behavior of this anthocyanin hydrolysis together with the CZE mobility allowed us to identify an unknown CZE peak as delphinidin 3-O-beta -arabin oside. At low TFA concentration, significant decomposition of the anthocyan idin nucleus occurred, but the glycoside hydrolysis predominated at high TF A concentration. It was further revealed that the aglycon released reacted successively to form polymeric products at higher TFA conditions.