The degradation of anthocyanic pigments of fresh and industrial juices from bloodoranges were studied during storage periods of a few days at 218 °C and 12 months at4 °C in nitrogen. The change of anthocyanin pigments was followed by HPLC at 520 nmwhile the coloured polymeric pigments were fractionated by chromatography and char-acterized by their transformation indices and their reactivity with NaHSO3. The resultsshow that the process of polymerization is accompanied by production of chemical indi-cators of sugar and ascorbic acid degradation (furfural and hydroxymethylfurfural). Itseems that the resulting polymeric compounds have structures different from those of thecompounds formed during wine processing. Reactions between anthocyanic pigments andthe intermediates of degradation of sugar and ascorbic acid in an acidic environment arethe main causes of formation of these polymers