A process for the preparation of photo-stable, water-soluble curcumin from Turmeric(Curcuma longa)

The present invention relates to an improved process for the preparation of water-soluble pigment formulations of improved photo-stability from Turmeric spice (Curcuma longa) of Zingiberaceae family. Curcuminoids, the color principles of turmeric are soluble in organic solvents like acetone and ethyl acetate but insoluble in water at acidic or neutral pH. Curcuminoids are known to lose color upon exposure to air and light possibly due to oxidation reactions. The prior art shows preparation of curcumin derivatives of simple and complex sugar molecules and also of various metals to achieve higher solubility or dispersability of the pigment in aqueous based systems. However, in these cases the required stability of the pigments against oxidative and thermal stress is not achieved. In the present invention, curcumin has been rendered water-soluble by use of a suitable emulsifier and then selected additives were employed for the enhancement of photo-stability of the pigment in the aqueous based systems, wherein the pigment is highly prone to photo-degradation. The innovation encompasses the synergistic use of combination of TBHQ with piperine or ascorbyl palmitate for achieving the photo-stability of curcumin.