the carotenoids which can be used in the practice of this invention are the known natural or synthetic available representatives of this class of compounds useful as coloring agents , e . g . carotene , lycopene , bixin , zeaxanthin , cryptoxanthin , lutein , canthaxanthin , β - apo - 8 &# 39 ;- carotenal , β - apo - 12 &# 39 ;- carotenal , β - apo - 8 &# 39 ;- carotenoic acid , and esters of hydroxy - or carboxy - containing members of this group , such as lower alkyl esters and , preferably , methyl and ethyl esters . the above carotenoids can be employed singly or in admixtures , depending on the color desired . especially preferred is canthaxanthin which either can be obtained from natural sources or prepared synthetically . water - dispersible powders containing from 2 . 5 to 15 % by weight of canthaxanthin can be prepared by the process of this invention . the clarity of aqueous compositions containing these powders dispersed therein is excellent . these aqueous canthaxanthin compositions are red in color , optically clear and have marked coloring ability which is useful for the coloring of products where optical clarity is important , i . e ., fruit juices , syrups , confections and the like . beadlets containing 1 % zeaxanthin , prepared by the process of this invention , when fed to hens cause marked improvement in egg yolk pigmentation as compared to egg yolk pigmentation using a zeaxanthin of large particle size . the quantity of sodium lauryl sulfate which is used in the emulsification process to provide optimum emulsification of the ingredients of the oil phase may vary from about 1 percent to about 6 percent by weight based on the weight of the powder composition . higher amounts of sodium lauryl sulfate may be used without deleterious effects on the final powders but no particular advantage is achieved by the use of such higher amounts . the carotenoid powder compositions of this invention contain , in addition to the carotenoid and sodium lauryl sulfate , from about 75 % by weight to about 90 % by weight , based on the weight of the powder composition , of an edible , pharmaceutically acceptable , water - soluble carrier composition which comprises a carbohydrate , e . g ., sucrose , fructose , lactose , invert sugar and the like , and a water - soluble protective colloid , e . g . gelatin , modified food starch and the like , wherein the weight ratio of water - soluble protective colloid to carbohydrate ranges from about 1 / 1 to about 2 / 1 . the modified food starches are the products of the treatment of any of several grain - or root - based native starches ( e . g ., corn , sorghum , wheat , potato , tapioca , sago , etc .) with small amounts of certain chemical agents which modify the physical characteristics of the native starches to produce desirable properties . a preferred modified food starch for use in compositions of this invention is a starch ester -- starch sodium octenyl succinate . in addition , the carotenoid powder compositions contain from about 0 . 01 % by weight , based on the weight of the powder composition , of an edible , pharmaceutically acceptable preservative , e . g . one or more of the following : benzoic acid , sodium benzoate , sorbic acid , potassium sorbate , methyl p - hydroxybenzoate ( methylparaben ), propyl p - hydroxybenzoate ( propylparaben ) and the like . from about 0 . 05 % by weight to about 0 . 3 % by weight , based on the weight of the carotenoid powder composition , of an edible , pharmaceutically acceptable stabilizing agent , e . g . ethylene diamine tetraacetic acid ( edta ) can be used to stabilize the emulsion against the effects of trace metals . the compositions of this invention also include from about 1 % by weight to about 10 % by weight , based on the weight of the carotenoid powder composition preferably from about 6 % to about 7 % by weight , of an edible , pharmaceutically acceptable antioxidant comprising one or more of such conventional substances as , for example , butylated hydroxyanisole ( bha ), butylated hydroxytoluene ( bht ), ascorbic acid and the tocoperhols . preferred is a blend of butylated hydroxytoluene and dl - α - tocopherol used at an optimal level of about 1 part of an equal quantity of each antioxidant for 1 to 2 parts of the carotenoid . the ph of the aqueous phase precursor of the emulsion is a critical factor since both sodium lauryl sulfate and the resulting emulsion are unstable at a ph of 7 . 0 or lower . in addition , spray dried carotenoid powders prepared from emulsions having these ph values of 7 . 0 or lower are also unstable and adversely affect the clarity of solutions prepared therefrom . preferably , the aqueous phase emulsion precursor should be within the ph range of 10 - 11 with a ph of 10 . 4 ± 0 . 2 optimal . using this aqueous phase ph range , the resulting emulsion ph after removal of chloroform and prior to spray drying can vary from about 9 to about 10 . the carotenoid powders prepared from such emulsions have improved stability and form , when dispersed in aqueous food preparations or solutions , products having the optical clarity of the original uncolored products . the modified emulsification technique employed in this invention involves the use of high - speed mixing ( i . e . from about 3 , 000 to 12 , 000 rpm ) coupled with a high shear force . the high shear force is essential to obtaining a small particle size for the carotenoid in the dispersed phase of the emulsion and a consequent small particle size for the carotenoid in the resulting dried carotenoid - containing powder compositions . high shear force relates to the applied forces which cause two contiguous parts of a body to slide relative to each other in a direction parallel to their plane of contact . the effective shear force is dependent on the solids content and the viscosity of the medium being mixed , the speed of mixing and the geometry of the mixer and the mixing vessel . a type of mixer which achieves this dual function of high speed mixing and high shear force is , for example , one employing a single shaft mixer with two separated , serrated circular horizonal shear plates set between two inverted feed cones on a single shaft . using a mixer of this type , as , for example , a lee turbon mixer , both high speed mixing and high shear force are rapidly achieved . what is important in achieving the water - dispersible carotenoid powders of this invention is the obtention of a shear force high enough to keep the particle size range of the droplets of the dispersed phase below 0 . 1 micron in diameter . thus , critical to the practice of this invention is the maintenance of both high speed mixing and high shear force during the removal of the volatile solvent . the combination of both the modified emulsification technique and the use of controlled ph in conjunction with the sodium lauryl sulfate emulsifier results in a significant decrease in the particle size of the carotenoid in the dispersed oil - phase of the emulsion to below 0 . 1 micron and a particle size range of less than 0 . 1 micron for the carotenoid in the resulting dried carotenoid - containing powder compositions . this carotenoid particle size is the major factor in obtaining the optically clear , aqueous compositions upon dispersal of the carotenoid - containing powder compositions in aqueous solutions and in providing enhanced bioavailability of the carotenoid particles when used in animal feedstuffs . the particle size of the dry carotenoid - containing powder compositions is , thus , not a critical factor per se . thus , water - dispersible powders containing from about 2 . 5 to about 15 % carotenoid can be prepared when sodium lauryl sulfate is used as the emulsifying agent . clarity of the aqueous compositons prepared from these carotenoid powder compositions containing the various percentages of the carotenoids is excellent . the volatile organic solvents suitable for use herein are those which are known solvents for the carotenoids . such solvents include halogenated aliphatic hydrocarbons , preferably polyhalogenated methane , e . g . chloroform , carbon tetrachloride and methylene chloride . however , other volatile solvents can also be used , such as benzene or carbon disulfide . chloroform is the preferred solvent . in a preferred process of this invention , the aqueous phase emulsion precursor containing sodium lauryl sulfate emulsifier , a water - soluble carrier composition ( gelatin , modified food starch and a sugar ), preservatives ( ascorbic acid , sorbic acid and sodium benzoate ) and a stabilizing agent ( edta ) is prepared and the ph is adjusted to between 10 - 11 with a base , e . g . sodium hydroxide . the oil phase emulsion precursor is prepared by dissolving the carotenoid and antioxidants , i . e ., bht and dl - α - tocopherol in chloroform or other suitable organic solvents . such other suitable solvents are , as noted earlier , halogenated aliphatic hydrocarbons , benzene or carbon disulfide . the carotenoid - containing oil phase is added to the aqueous phase using both high speed mixing and a high shear force . the high speed mixing and high shear force are continued after emulsification until all the volatile organic solvent has been removed by evaporation . the resulting emulsion is amenable to spray drying operations using a standard spray drying tower , to drying in beadlet form by double dispersion techniques or by spraying droplets into a collecting powder , to casting of the emulsion followed by drying and comminuting , to drum drying and to lyophilization techniques . using the above formulations , water - dispersible carotenoid - containing powder compositions containing from 2 to about 15 % by weight of the carotenoid can be prepared . the carotenoid constituent of such powder compositions have a particle size of less than 0 . 1 micron . the ability to form carotenoid - containing powder compositions having such a range of carotenoid concentration means , for example that quite a broad color range can be obtained in solution depending on the concentration of carotenoid in the powder . 330 grams of gelatin , 279 grams of sucrose , 0 . 75 grams of sorbic acid and 1 . 50 grams of sodium benzoate are added to 330 grams of distilled water . the gelatin mixture is solubilized by hydrating overnight at about 50 ° c . ______________________________________ascorbic acid 2 . 25 gramsedta 0 . 75 gramssodium laurylsulfate 12 . 0 gramsdistilled water 105 . 0 grams______________________________________ this solution is then added to the gelatin - sugar solution to form the aqueous phase of the emulsion . the ph of this solution is adjusted to 10 . 4 ± 0 . 2 using a 20 % w / w sodium hydroxide solution . ______________________________________canthaxanthin 23 . 3 gramsbutylated hydroxy - toluene ( bht ) 22 . 5 gramsdl - α - tocopherol 22 . 5 gramschloroform 525 grams , ______________________________________ is prepared by first dissolving the bht in dl - α - tocopherol by heating the mixture to 80 ° c . the solution is cooled to 55 ° c . and then mixed with the chloroform until a clear solution results . canthaxanthin is added to this solution under nitrogen atmosphere and dissolved . both the aqueous and oil phases are heated to about 50 °- 55 ° c . the oil phase is added slowly to the aqueous phase using both a high rate of mixing and a high shear force mixer . after the addition is completed , the emulsion temperature is maintained at 55 ° c . while high speed shear mixing is continued for 15 minutes . the temperature is gradually raised and mixing is continued until all the chloroform has been evaporated . this evaporation is usually completed when the temperature of the emulsion reaches about 75 ° c . during the evaporation procedure , distilled water is added to the emulsion to maintain a suitable viscosity . after all the chloroform has been removed sufficient distilled water is added to and thoroughly admixed with the emulsion to achieve an emulsion solids content and viscosity suitable for spray - drying . the emulsion is spray - dried under standard spray drying conditions using a spray drying tower . the carotenoid constituent of the resulting powder composition has a particle size which is below 0 . 1 micron . the spray - dried powder is free - flowing and dissolves in water to form very clear dispersions . when used in preparations intended to be reconstituted as clear fruit flavored gelatin - type desserts and in flavored aqueous beverages , the resulting products have excellent clarity and color . stability , i . e . the retention of the carotenoid in the water - dispersible powder , was measured both at room temperature and at 45 ° c . results are tabulated below . ______________________________________temperature , time , %° c . months container retention______________________________________room 3 closed 10045 1 open 9745 1 closed 10045 2 open 9745 2 closed 10045 3 open 9445 3 closed 100______________________________________ the following spray - dried water - dispersible carotenoid - containing powders were formed from emulsions prepared as described in example 1 and containing 5 . 0 , 7 . 5 and 10 %, of canthaxanthin : __________________________________________________________________________ 5 . 0 % 7 . 5 % 10 % __________________________________________________________________________canthaxanthin 46 . 6 grams 70 grams 93 gramsbht 22 . 5 grams 22 . 5 grams 22 . 5 gramsdl - α - tocopherol 22 . 5 grams 22 . 5 grams 22 . 5 gramssucrose 279 grams 279 grams 279 gramsgelatin 330 grams 330 grams 330 gramsascorbic acid 2 . 25 grams 2 . 25 grams 2 . 25 gramssodium benzoate 1 . 5 grams 1 . 5 grams 1 . 5 gramssorbic acid 0 . 75 grams 0 . 75 grams 0 . 75 gramsedta 0 . 75 grams 0 . 75 grams 0 . 75 gramssodium lauryl sulfate 22 grams 30 grams 40 gramssodium hydroxide ( 20 % w / w solution ) to adjustph of aqueous phase to 10 . 35 10 . 4 10 . 5final ph of emulsion 9 . 65 9 . 4 9 . 4spray dried powder , solution clarity very clear clear cleargelatin dessert test * very clear clear clearliquid beverage test * very clear clear clear with sl . opalescence__________________________________________________________________________ * reconstituted ______________________________________ temperature , time , % sample ° c . months container retention______________________________________5 % room 3 closed 1005 % 45 1 open 1025 % 45 1 closed 1035 % 45 2 open 1005 % 45 2 closed 1035 % 45 3 open 945 % 45 3 closed 100 7 . 5 % 45 1 open 100 7 . 5 % 45 1 closed 10010 % 45 1 open 9810 % 45 1 closed 94______________________________________ a water - dispersible spray - dried β - apo - 8 &# 39 ;- carotenal powder containing 5 % β - apo - 8 &# 39 ;- carotenal and having the composition as listed below was prepared by spray - drying an emulsion prepared as described in example 1 . ______________________________________apocartenal 31 . 0 gramsbht 15 . 0 gramsdl - α - tocopherol 15 . 0 gramsgelatin 135 . 0 gramsmodified food starch 135 . 0 gramssucrose 135 . 0 gramsascorbic acid 1 . 5 gramssorbic acid 0 . 5 gramssodium benzoate 1 . 0 gramsedta 0 . 5 gramssodium lauryl sulfate 15 . 0 gramssodium hydroxide q . s . to aqueous ( 20 % w / w / solution ) phase ph of 10 . 4______________________________________ beadlets containing 1 % zeaxanthin and having the composition listed below were prepared from an emulsion prepared as described in example 1 . ______________________________________zeaxanthin 17 . 1 gramsbht 22 . 5 gramsdl - α - tocopherol 22 . 5 gramssucrose 279 gramsgelatin 330 gramsascorbic acid 2 . 25 gramssodium benzoate 1 . 5 gramssorbic acid 0 . 75 gramsedta 0 . 75 gramssodium lauryl sulfate 7 . 4 gramssodium hydroxide q . s . to ph 10 . 4 ( 20 % w / w solution ) ______________________________________ an apparatus provided with a revolving spray head and a counter - rotating drum was used to prepare the beadlets . in this apparatus the emulsion is forced through tiny orifices of the revolving spray head . the resulting droplets contact the powdery starch material which is suspended in air in the rotating drum . the drum and the spray head are rotated in opposite directions so that the suspension of the starchy powder in air is swirled in a direction of rotation opposite to the entering droplets of the emulsion spray . the emulsion obtained was loaded into the revolving spray head . the drum was loaded with 2 kg . of &# 34 ; dry - flo &# 34 ;, previously dried to a moisture content of about 3 percent . after all the emulsion had been collected in the &# 34 ; dry - flo &# 34 ;, the mixture of starch and beadlets was allowed to stand for about an hour and then screened through a 150 mesh screen . the carotenoid - containing particles retained upon the screen were collected , spread out on drying trays and then dried in an oven . the dry , free - flowing beadlets are suitable for use in animal feedstuff . when fed to hens , the small particle size of the zeaxanthin contained therein enhanced the yolk pigmenting effect .
this invention relates to water dispersible carotenoid compositions in liquid or powder form which are suitable for use in the preparation of colored optically clear , stable , aqueous compositions and which can be incorporated into , e . g ., pharmaceutical or cosmetic preparations or animal feedstuff and to processes for their preparation .