Annatto, i.e. the orange coloring matter from the pulp of the fruit seeds of the evergreen Bixa orellana is acceptable for use as a coloring in foods and is known to be useful in the coloration of cheese and milk. Annatto is soluble in water at a basic pH and can be obtained commercially in aqueous, basic solution. The material can be used as a coloring in the form of its solution or the pigment can be dispersed in various emulsifying agents and incorporated into the food to be colored in this form.
Annatto would be a desirable colorant for dry powdered beverages and dessert mixes, however, there is not presently available an annatto colorant in dry form which is resistant to precipitation at the low pHs commonly encountered when these materials are dissolved in water.
The use of pH sensitive dyes in dry food formulations is not new. For example, U.S. Pat. No. 4,307,117 discloses a dry food mix employing curcumin which has been dispersed in an aqueous film-forming solution containing an acid and drying the solution to render the alkaline sensitive colorant stable to food mixes even at basic pHs.
In U.S. Pat. No. 3,455,838, there is disclosed a method for encapsulating water insoluble substances which involves the spray-drying of an aqueous dispersion of a dextrinized starch acid-ester of a substituted dicarboxylic acid in which the water insoluble substance has been emulsified. The encapsulated particles are useful in the preparation of foods, pharmaceuticals and cosmetics. In using these acid-ester dextrins as encapsulating agents for the entrapment of oils and other water insoluble substances, it is first necessary to disperse or dissolve them in water to form a solution or dispersion by adding the dextrin to hot water with agitation whereupon the water insoluble substance to be entrapped is slowly added and the mixture rapidly agitated until emulsification is complete. The resulting emulsion is then dried by suitable means such as spray-drying.