PREPARATION OF SPHERICALLY AGGLOMERATED CRYSTALS OF THE 3,5-DIGLUCOSIDE OF CYANIDIN (CYANIN)

Suitable proportions of the solvent mixture benzene:methanol:aqueous h ydrochloric acid to yield the spherically agglomerated crystals of cya nin have been found. The physicochemical properties and dissolution ra te of the agglomerates, in comparison with the crystals obtained by a conventional method, have been analysed. No change in the crystalline form of the basic crystals was found in acid conditions, after agglome ration. The dissolution rate of spherical agglomerates did not decreas e as much as predicted from their low specific surface areas because o f their improved wettability. The crystallization speed would not only avoid colour loss during the isolation and purification of anthocyani ns from their natural sources, but also would increase production, sav e time and cost. On the other hand, a decrease in the specific surface areas will reduce powder hygroscopicity with subsequent technological and stability advantages.