Curcumin is water insoluble which limits its usage in water based foods and pharmaceutical applications. For making it water soluble it is conjugated to N acetylanine PEG carboxylic acid by a carbodiimide mediated esterification at phenolic hydroxyl groups. The reaction should stsndardized with polyethylene glycols. Curcumin also do make water soluble by use of an emulsifier like Tween-60. Curcumin also form inclusion complex with cycylodextrin. Curcumin is the yellow pigment associated with the curry spice, Turmeric, and to a lesser extent Ginger. It is a small molecule that is the prototypical 'curcuminoid', and has effects similar to other polyphenols but unique in a way as it is a different class of polyphenol (relative to the other classes of 'flavonoid', 'stilbene', etc.Curcumin (chemically known as Diferuloylmethane) is the main active ingredient of the spice Turmeric (Curcuma Longa or JiangHuang) and is the main 'curcuminoid' compound (80% of curcuminoid weight is curcumin[1]) alongside the other three curcuminoids known as demethoxycurcumin, bisdemethoxycurcumin, and cyclocurcumin .