The phenolic compounds of blackcurrant juice and their protective effect on ascorbic acid

Summary. The oxidation of ascorbic acid in citrate buffer at pH 2.9 has been investigated with and without added copper ions as catalyst, and the loss of ascorbic acid followed by polarographic analysis. Certain flavonoids occurring in blackcurrant juice were used as antioxidants and their activity, in the absence of added copper ions, was found to decrease in the order, quercetin and dihydroquercetin (equal), kaempferol and rutin....