Water dispersible compositions containing natural hydrophilic, water-insoluble pigments, methods of preparing same and their use

Abstract

Ready-to-use water dispersible pigment compositions containing water-insoluble, hydrophilic pigments are provided. The compositions comprise a stable dispersion of the pigment such as a porphyrin pigment, carmine, curcumin and a carotenoid in the form of bodies of an average size which is at the most 10 μm is provided. The pigment bodies are dispersed without the use of a surface active substance in an aqueous phase comprising a hydrocolloid. The natural pigment compositions which are useful for coloring of food products and pharmaceuticals do not migrate in the products and they are acid stable. The compositions are useful in coating compositions for tablets and dragees.

1 . A ready-to-use water dispersible pigment composition that contains in excess of 10% by weight of water, the composition comprising a dispersion of a water-insoluble hydrophilic natural pigment in the form of bodies of an average size which is at the most 10 μm, said bodies being dispersed in the absence of a surface active substance in an aqueous phase comprising a hydrocolloid, the composition, when it is added to a food product or a pharmaceutical product comprising multiple, separated compartments, whereby the composition is dispersed in one or more selected compartments, essentially does not migrate from said compartment(s) where it is dispersed into other compartments.  
     
     
         2 . A ready-to-use water dispersible pigment composition comprising a dispersion of a water-insoluble, hydrophilic natural pigment in the form of bodies of an average size which is at the most 10 μm, said bodies being dispersed in the absence of a surface active substance in an aqueous phase comprising a hydrocolloid, the composition containing less than 5% by weight of water, subject to the limitation that when the pigment is carmine or spray dried norbixin the hydrocolloid is not gelatin, said composition, when it is added to a food product or a pharmaceutical product comprising multiple, separated compartments, whereby the composition is dispersed in one or more selected compartments, essentially does not migrate from said compartment(s) where it is dispersed into other compartments.  
     
     
         3 . A composition according to  claim 1  or  2  wherein the natural pigment is a pigment that is generally insoluble in aqueous media at about neutral pH or below but soluble in aqueous media at pH values in the alkaline range.  
     
     
         4 . A composition according to  claim 3  wherein the pigment is selected from the group consisting of a porphyrin pigment, carmine, curcumin and a carotenoid.  
     
     
         5 . A composition according to  claim 4  wherein the pigment is in the form of particles obtained by precipitation of the pigment caused by acidifying an alkaline solution of the pigment.  
     
     
         6 . A composition according to any of claims  1 - 5  wherein the aqueous phase comprises a carbohydrate.  
     
     
         7 . A composition according to  claim 1  or  2  wherein the hydrocolloid is selected from a protein, a polysaccharide and a gum.  
     
     
         8 . Use of a ready-to-use water-dispersible composition comprising a dispersion of a hydrophilic natural pigment in the form of bodies of an average size which is at the most 10 μm, said bodies being dispersed in the absence of a surface active substance in an aqueous phase comprising a hydrocolloid, the composition containing in excess of 10% by weight of water, in the manufacturing of an edible product whereby the composition is dispersed in an aqueous phase of said edible food product.  
     
     
         9 . Use of a composition according to  claim 2  in the manufacturing of an edible product whereby the composition is dispersed in an aqueous phase of said edible food product  
     
     
         10 . Use according to  claim 8  or  9  wherein the aqueous phase has a pH which is at the most 7.  
     
     
         11 . Use according to  claim 8  or  9  in the manufacturing of an edible product comprising multiple, separated compartments whereby the composition is dispersed in one or more selected compartments, the composition in one compartment essentially not migrating to other compartments.  
     
     
         12 . Use of a ready-to-use water-dispersible composition comprising a dispersion of a hydrophilic natural pigment in the form of bodies of an average size which is at the most 10 μm, said bodies being dispersed in the absence of a surfact active substance in an aqueous phase comprising a hydrocolloid, the composition containing in excess of 10% by weight of water, in the manufacturing of a pharmaceutical product.  
     
     
         13 . Use of a composition according to  claim 2  in the manufacturing of a pharmaceutical product.  
     
     
         14 . Use according to  claim 12  or  13  wherein the pharmaceutical product comprises multiple, separated compartments whereby the composition is dispersed in one or more selected compartments, she composition in one compartment essentially not migrating to other compartments.  
     
     
         15 . An edible product comprising a composition according to any of claims  1 - 7 .  
     
     
         16 . A pharmaceutical product comprising a composition according to any of claims  1 - 7 .  
     
     
         17 . A method of preparing a ready-to-use water dispersible pigment composition according to any of claims  1 - 7 , said method comprising preparing a dispersion of a water-insoluble, hydrophilic natural pigment by mixing the pigment in the absence of a surface active substance into an aqueous phase containing a hydrocolloid, to obtain a dispersion comprising the pigment in the form of bodies having an average size of at the most 10 μm, the composition containing at least 10% by weight of water.  
     
     
         18 . A method according to  claim 17 , which comprises the further step of drying the dispersion to obtain a composition containing less than 5% by weight of water, subject to the limitation that, when the pigment is carmine or spray-dried norbixin, the hydrocolloid is not gelatin.  
     
     
         19 . A method according to  claim 17  or  18  wherein the solid pigment is in the form of particles obtained by precipitation of the pigment caused by acidifying an alkaline solution of the pigment.  
     
     
         20 . A method according to  claim 17  or  18  wherein the amount of hydrocolloid is less than 10% by weight calculated on the pigment.  
     
     
         21 . A method according to  claim 17  or  18  which comprises a further step wherein an additional amount of hydrocolloid is added.  
     
     
         22 . A method according to  claim 17  or  18  wherein a carbohydrate is added to the aqueous phase.  
     
     
         23 . A method of preparing a ready-to-use water dispersible pigment composition, said method comprising the steps of: 
 i) preparing an alkaline aqueous solution comprising a water-insoluble, hydrophilic natural pigment,    ii) preparing an aqueous dispersion or solution of a hydrocolloid,    iii) mixing the alkaline aqueous solution with the aqueous dispersion or solution of a hydrocolloid and    iv) if desired, adjusting the pH to a level which causes the pigment to precipitate,    to obtain the composition comprising the pigment in the form of a dispersion of pigment bodies having an average size of at the most 10 μm, the composition containing at least 10% by weight of water.    
     
     
         24 . A method according to  claim 23 , which comprises the further step of drying the composition of pigment bodies to obtain a composition containing less than 5% by weight of water, subject to the limitation that, when the pigment is carmine or spray-dried norbixin, the hydrocolloid is not gelatin.  
     
     
         25 . A method of preparing a ready-to-use water dispersible pigment composition, said method comprising the steps of: 
 i) preparing an alkaline aqueous solution comprising a water-insoluble, hydrophilic natural pigment followed by decreasing the pH to a level which causes the pigment to precipitate, resulting in a dispersion of precipitated pigment,    ii) preparing an aqueous dispersion or solution of a hydrocolloid,    iii) mixing the dispersion comprising the precipitated pigment of step i) and the dispersion or solution of the hydrocolloid of step ii),    to obtain the composition comprising the pigment in the form of dispersions of pigment bodies having an average size of at the most 10 μm, the composition containing at least 10% by weight of water.    
     
     
         26 . A method according to  claim 25 , which comprises the further step of drying the composition of pigment bodies to obtain a composition containing less than 5% by weight of water, subject to the limitation that, when the pigment is carmine or spray-dried norbixin, the hydrocolloid is not gelatin.  
     
     
         27 . A method according to of  claim 23  wherein the aqueous solution of step i) and/or the dispersion or solution of step ii) comprises a carbohydrate.  
     
     
         28 . A method according to  claim 25  wherein the dispersion comprising the precipitated pigment of step i) and the dispersion or solution of the hydrocolloid of step ii) comprises a carbohydrate.