Stable vitamin and/or carotenoid products in powder form, and the preparation thereof

A process for preparing stable dry powders which are insoluble in hot water and which contain fat-soluble vitamins and/or carotenoids, which comprises the following steps: PA1 a) preparing an aqueous dispersion containing essentially these fat-soluble active substances, film-forming colloids and reducing sugars, PA1 b) converting this dispersion into dry vitamin and/or carotenoid products in powder form and PA1 c) thermally curing the powder at from 60.degree. to 180.degree. C., wherein gelatin in combination with one or more organic amino compounds which are free or bonded in the manner of a salt and which contain a basic primary amino group and, in addition, either another amino group, a hydroxyl group, an alkoxy group or a carboxyl group, and/or in combination with sufficient basic alkali metal or alkaline earth metal compound for the dispersion to have a pH of from 7.5 to 10, is used as film-forming colloid, and the dry powders obtainable via this process are described.

The present invention relates to stable dry powders which are insoluble in 
hot water and in which one or more fat-soluble vitamins and/or one or more 
carotenoids are embedded in a gelatin-based matrix, obtainable by 
a) preparing a dispersion containing essentially these fat-soluble active 
substances, reducing sugars and, as film-forming colloid, gelatin in 
amounts of from 20 to 35, preferably 24 to 34, in particular 25 to 30, % 
of the weight of the powder dry matter, in combination with one or more 
physiologically tolerated organic amino compounds which contain a basic 
primary amino group and, in addition, either another amino group, a 
hydroxyl group, an alkoxy group or a carboxyl group, in free form or in a 
form bonded in the manner of a salt, and/or in combination with sufficient 
basic alkali metal or alkaline earth metal compound for the dispersion to 
have a pH of from 7.5 to 10, preferably 8 to 9.5, 
b) converting this dispersion into dry vitamin and/or carotenoid products 
in powder form and 
c) thermally curing the powder at from 60.degree. to 180.degree. C., 
preferably 70.degree. to 130.degree. C., and to a process for the 
preparation thereof. 
Vitamin and carotenoid products in powder form are generally known and are 
used in large quantities in the pharmaceutical industry and in the food 
and animal feed industries. Thus, many processes for preparing suitable 
products are described in the literature. 
Conventionally, the fat-soluble vitamins and/or carotenoids are dispersed 
in an aqueous solution of an organic film-forming colloid and the 
resulting dispersion is finally converted into dry products in powder 
form. 
Gelatin is conventionally used in the prior art as film-forming colloid. 
Reasons which may be mentioned for preferring gelatin are: 
1) gelatin is an excellent dispersion-stabilizing and film-forming agent; 
2 ) gelatin forms thermoreversible gels, which means that it is 
industrially possible with suitable processes to dry the droplets or 
beadlets of the dispersion and thus obtain particles of optimal size; 
3) gelatin is a good protective colloid and, in combination with 
antioxidants, has a stabilizing effect, i.e. the protective film is 
particularly impermeable to oxygen, which is particularly important for 
the fat-soluble vitamins which are particularly sensitive to oxygen (cf. 
R. A. Morton in Fat-soluble Vitamins, International Encyclopaedia of Food 
and Nutrition, Vol. 9, Pergamon Press Ltd., 1970, pp. 129 et seq.). 
The stability of such products must meet particularly stringent 
requirements when they are to be used as additives to foodstuffs or to 
animal feeds, because when used for these they are often exposed to 
influences such as elevated temperatures, moisture, mechanical friction or 
pressure which are extremely damaging for the sensitive vitamins and 
carotenoids. This is why there has been no lack of attempts to develop 
processes which provide products with particular thermal and mechanical 
stability. 
Thus, for example, GB 993 138 discloses the stabilization of certain 
vitamin products which contain gelatin as matrix by the particles being 
treated with a gelatin-denaturing agent such as formaldehyde, glyoxal, 
acetaldehyde or dihydroxyacetone, and subsequently heated, or else 
subjected only to a heat treatment. 
The recently published Patent EP-B1 285 682 discloses a process for 
preparing spherical products which contain fat-soluble vitamins by 
emulsion formation using water, gelatin and a sugar, converting the 
emulsion into droplets, collecting the droplets in a mass of starch powder 
in such a way that the droplets remain separated from one another until 
their shape has been permanently formed, separating the resulting 
particles from excess starch powder and subsequently heating at from 
90.degree. to 180.degree. C. The disadvantage of the process, which is 
intrinsically quite good, is that relatively large amounts of gelatin 
(from 35 to 45% of the weight of the dry matter) are required to prepare 
the products, which makes industrial preparation of the products 
uneconomic in view of the costs of the materials used and the process. 
It is an object of the present invention to prepare vitamin and/or 
carotenoid products in powder form which have a lower content of costly 
gelatin but at least equivalent stability to hydrothermal and mechanical 
stress and are thus more suitable for producing, for example, premixes, 
pellets and extrudates for animal feed, and tablets for the drug sector. 
We have found that this object is achieved by a process by which the 
above-defined stable dry powders which are insoluble in hot water and 
which contain one or more fat-soluble vitamins and/or one or more 
carotenoids can be obtained and which comprises the following steps: 
a) preparing an aqueous dispersion containing essentially these fat-soluble 
active substances, film-forming colloids and reducing sugars, 
b) converting this dispersion into dry vitamin and/or carotenoid products 
in powder form, preferably by spraying into a cloud composed of a gas and 
hydrophobic silica, and 
c) thermally curing the powder at from 60.degree. to 180.degree. C., 
wherein gelatin in amounts of from 20 to 35% of the weight of the powder 
dry matter, in combination with one or more physiologically tolerated 
organic amino compounds which are free or bonded in the manner of a salt 
and which contain a basic primary amino group and, in addition, either 
another amino group, a hydroxyl group, an alkoxy group or a carboxyl 
group, which is free or bonded in the manner of a salt and/or in 
combination with sufficient basic alkali metal or alkaline earth metal 
compound for the dispersion to have a pH of from 7.5 to 10, is used as 
film-forming colloid. 
The process according to the invention is advantageously carried out in 
such a way that the gelatin is used in amounts of from 24 to 34%, in 
particular 25 to 30%, of the weight of the powder dry matter, in 
combination with from 0.3 to 20% by weight, preferably 0.5 to 10% by 
weight, based on the powder dry matter, of amino compound which is free or 
bonded in the manner of a salt, the total of the amount of gelatin and the 
amount of amino compound not exceeding 45% by weight, preferably 40% by 
weight, in particular 35% by weight. 
Although the use of amino acids and reducing sugars for preparing 
formulations in powder form of fat-soluble vitamins and the drying thereof 
on exposure to heat is described in JA-B 45-38348 (published 1970), this 
describes only vitamin powders based on alkali metal salts of casein, but 
not on gelatin. However, since casein, in contrast to gelatin, does not 
form thermo-reversible gels it is only possible in this way to obtain very 
fine-particle products which are not very suitable, for example, for use 
under hydrothermal stress because they are dispersible in water. 
By contrast, the products in powder form produced according to the 
invention have excellent stability and insolubility in hot water. These 
properties are even evident in comparison with powders which have a high 
gelatin content but no amino compounds and are particularly important for 
use in animal feeds because in these the vitamin- and 
carotenoid-containing powders are exposed to chemical, mechanical and/or 
hydrothermal stress in premixes and during processing to pellets, 
extrudates or tablets. It should also be mentioned that the 
bioavailability of the active substances enclosed in the powders obtained 
according to the invention is completely retained. 
The amino compounds can also according to the invention be used together 
with a basic alkali metal or alkaline earth metal compound such as an 
alkali metal or an alkaline earth metal hydroxide, an alkaline earth metal 
oxide or an alkaline earth metal or alkali metal carbonate. However, it is 
also possible for the basic compounds to be used in place of the amino 
compounds. When basic compounds are used it is most expedient for the 
process to be such that the dispersion has a pH of from 7.5 to 10, 
preferably 8 to 9.5, in particular 8 to 9, after addition of the basic 
compound. 
The thermal treatment of the initially obtained powder results in the 
gelatin content being denatured owing to reaction of its free amino groups 
with the reducing sugars (Maillard reaction) and thus becoming insoluble 
in water. This effect is synergistically enhanced by the presence of the 
amino compounds described above, especially amino carboxylic acids, which 
assist crosslinking of the matrix by polymer formation. This means that 
part of the gelatin, which would be necessary in the prior art processes 
can be replaced by in each case considerably smaller amounts of the amino 
compounds described. When basic compounds are added there is presumably 
activation of the amino groups of a gelatin, which might explain why this 
also makes it possible to reduce the amount of gelatin required. Another 
advantage of the process according to the invention is that the customary 
crosslinking temperatures are reduced in the presence of the amino 
compounds and/or the basic compounds, i.e. crosslinking is possible at 
60.degree. C. or above, while the crosslinking temperatures required 
according to EP 285 682 are from 90.degree. to 180.degree. C., preferably 
105.degree. to 150.degree. C. It is thus possible in the process 
according to the invention to reduce the thermal stress of the active 
substances during preparation compared with the process of EP 285 682. 
The fat-soluble vitamins include vitamins A, E, D and K as well as mixtures 
thereof. For the purpose of the present invention they can be employed in 
the form of vitamin solutions in oils, as provitamins and as pure vitamins 
of natural or synthetic origin. Particularly interesting products contain 
vitamin A and its derivatives, especially vitamin A acetate, vitamin A 
palmitate and vitamin A propionate, and mixtures thereof. 
By carotenoids are meant compounds such as .beta.-carotene, ethyl 
apo-8'-carotenoate, apo-8'-catorenal, citranaxanthin, canthaxanthin, 
zeaxanthin, astaxanthin, lutein, capsanthin and mixtures thereof. 
The contents of vitamins or carotenoids are generally from about 5 to 50%, 
preferably 10 to 35%, of the weight of the powder dry matter. 
The dispersion can be prepared in the process according to the invention 
using gelatin of the A or B type in a wide Bloom range. It is particularly 
advantageous to use gelatin with a Bloom value of from about 50 to about 
250. 
The dispersion can be prepared using all reducing sugars or sugar syrups 
containing reducing sugars. Reducing sugars include fructose, glucose, 
lactose, maltose, xylose, arabinose, ribose and invert sugar 
(glucose+fructose), honey, fructose syrups and glucose syrups. The sugars 
are generally used in amounts of from about 3 to 25% of the weight of the 
dry matter. 
Suitable organic amino compounds which contain a basic primary amino group 
and, in addition, either another amino group, a hydroxyl group, an alkoxy 
group or a carboxyl group are thus aliphatic diamines such as 
ethylenediamine or hexamethylenediamine, alkanolamines such as 
ethanolamine, propanolamine or butanolamine, amino ethers such as 
2-methoxyethylamine or 3-methoxypropylamine, or amino carboxylic acids in 
free form or in a form bonded in the manner of a salt. The use of amino 
carboxylic acids or of their salts has particular significance. 
Suitable amino carboxylic acids are all natural and synthetic amino acids 
in their L form, D form or as racemate. The amino carboxylic acids can be 
.alpha.-, .beta.- or .omega.-amino carboxylic acids in free form or in the 
form of salt-like compounds with acids or bases. Examples are glycine, 
.alpha.-alanine, .beta.-alanine, valine, .gamma.-aminobutyric acid, 
leucine, isoleucine, tyrosine, serine, methionine, arginine, 
phenylalanine, tryptophan or lysine, or else salts of the said amino 
acids. 
It is of course also possible to use as amino carboxylic acid component 
mixtures of amino carboxylic acids which are free or in salt form, such as 
protein hydrolysates. 
It is particularly advantageous to use readily accessible and thus low-cost 
amino carboxylic acids or their salts, such as lysine hydrochloride or 
calcium .beta.-alaninate, especially calcium .beta.-alaninate. 
The amino compounds are generally used in amounts of from about 0.3 to 20%, 
preferably 0.5 to 10%, of the weight of the powder dry matter. 
The gelatin is used according to the invention in amounts of from 20 to 
35%, preferably 24 to 34%, in particular 20 to 30%, of the weight of the 
powder dry matter. 
The dry powders according to the invention and their preparation have 
advantages over the known products when the total of the amount of gelatin 
and the amount of the organic amino compound does not exceed 45% by 
weight, preferably 40% by weight, in particular 35% by weight. 
In addition to the obligatory ingredients, it is advantageous to add to the 
dispersion other compounds customary in the preparation of active 
substance dry powders. 
It is particularly important when the dry powders are used as animal feed 
additives in the case of active substances which are sensitive to 
oxidation to add antioxidants such as ethoxyquin, butylated hydroxytoluene 
(BHT), butylated hydroxyanisole (BHA) or tocopherol, and stabilizers such 
as citric acid, phosphoric acid or phytic acid and their alkali metal or 
alkaline earth metal salts, or else complexing agents such as 
ethylenediaminetetraacetic acid (EDTA) or nitrilotriacetic acid (NTA). 
However, the emulsion frequently also contains added humectants such as 
glycerol, sorbitol or polyethylene glycols or else additional emulsifiers 
such as lecithin. 
In addition, additives such as starch, especially corn starch or 
maltodextrin, or thickeners such as gum arabic, guar gum, alginates and 
certain degraded starches, have proven useful for adjusting the viscosity 
of the emulsion. 
For details of the importance, nature and amount of such additives, 
reference may be made to the relevant literature, for example to the 
abovementioned monograph entitled Fat-soluble Vitamins, Vol. 9, especially 
pages 128-133. 
The process according to the invention is generally carried out in such a 
way that the dispersion containing the active substance is prepared by 
dissolving gelatin in hot water (at 50.degree.-70.degree. C.), adding to 
the solution the sugars, the amino compounds, the vitamins and/or 
carotenoids, stabilizers and the other conventional additives, with or 
without additional water, and dispersing the mixture by vigorous agitation 
at elevated temperature. For the thermal crosslinking of the powder which 
takes place in the last step, the dispersion should be at pH 4-10, which 
can be adjusted by adding bases such as NaOH, KOH, Ca(OH).sub.2, MgO, 
sodium carbonate or NH.sub.4 OH. 
The subsequent processing of the dispersion to give the powders according 
to the invention can take place by all the processes known from the 
literature. 
Because of the required particle size distribution of the powders (diameter 
from 0.1 to 0.6 mm), the preferred processes include measures to keep the 
gelled droplets of the dispersion separate from one another until the 
shape has stabilized. 
Examples which may be mentioned are the process disclosed in EP-B1 74050 in 
which the dispersion is sprayed into hydrophobic silica or a metal salt of 
a higher fatty acid, or else the process disclosed in EP-B1 285 682 in 
which the dispersion is sprayed into starch powder. It has emerged that, 
especially in processes used for preparations with gelatin contents below 
35% by weight, the spraying can very particularly advantageously be 
carried out with hydrophobic silica as dusting powder. 
The powders produced by the described processes have, after drying, a water 
content of less than 10%, normally less than 6%. The products in powder 
form obtained in this way are composed of particles with a good surface 
structure. They rapidly dissolve in water at about 40.degree. C. to give a 
milky dispersion. 
The thermal curing of the dried powder is carried out at from 60.degree. to 
180.degree. C., and the rate of the crosslinking which takes place 
increases as the temperature rises. The crosslinking is preferably carried 
out at from 70.degree. to 130.degree. C. over the course of from 5 minutes 
to 3 hours. The powders prepared in this way are insoluble in boiling 
water and have excellent stability, as is shown by the stability test on 
vitamin A acetate dry powder described hereinafter. 
The process according to the invention can be used to prepare stable 
vitamin and/or carotenoid dry powders which are insoluble in hot water and 
which, despite the use of only about 20 to 35% by weight, based on the 
powder dry matter, of gelatin, compared with about 40 to 45% by weight in 
the prior art, have a stability which is at least as good. 
Stability Test 
A vitamin A acetate dry powder based on gelatin and lysine (cf. Example 3) 
according to the invention was compared with a vitamin A acetate dry 
powder containing only gelatin but prepared in the same way (cf. 
Comparative Example 4). Both dry powders were subjected to the premix 
stress test (40.degree. C./70% relative humidity), which is described 
hereinafter, both as only dried (i.e. uncrosslinked) product and as 
product crosslinked by thermal treatment. 
The premix had the following composition: 
______________________________________ 
Wheat bran 60% 
Choline chloride (50% on SiO.sub.2) 
30% 
Trace element mix 10% 
______________________________________ 
The trace element mix was composed of: 
______________________________________ 
CuSO.sub.4.5 H.sub.2 O 
37.43% 
FeSO.sub.4.7 H.sub.2 O 
46.78% 
ZnO 11.79% 
MnO 3.61% 
CoCO.sub.3 0.39% 
______________________________________ 
In each case 1 g of vitamin A dry powder was mixed into 99 g of the premix 
and then 4 g of this mixture were stored at 40.degree. C. and 70% relative 
humidity, checking the vitamin A content at the start and after 4 weeks. 
The vitamin A contents after 4 weeks are shown in the following Table as a 
percentage of the initial contents. 
A comparable indicator of the stability is the enzymatically detectable 
sugar content remaining after crosslinking. As the degree of crosslinking 
increases, the detectable sugar content of the powder decreases and, 
conversely, the stability increases. The residual sugar contents are 
therefore also indicated in the following Table. Other examples of the 
residual sugar content after crosslinking are given in the Examples. 
______________________________________ 
Dry powder of Ex. 3 
Dry powder of Ex. 4 
a) un- a) un- 
cross- 
b) cross- cross- b) cross- 
linked 
linked linked linked 
______________________________________ 
Retention 64% 83% 60% 77% 
after 4 
weeks 
Residual 9% 3.6% 9% 6.4% 
fructose 
______________________________________ 
The stability test shows that thermally crosslinked vitamin A dry powders 
are distinctly more stable than the uncrosslinked starting materials. 
Furthermore, the vitamin A dry powder according to the invention (Example 
3 containing 25% gelatin and 2.5% lysine) is even more stable than the 
vitamin A dry powder of Comparative Example 4 (40% gelatin, 0% lysine). 
Comparison of the stability data on dry powders in the previously described 
premix test also reveals a distinct increase in stability when the spray 
dispersion is adjusted with basic compounds to a higher pH. This is shown 
by comparison of following Examples 19 and 20.

EXAMPLE 1 
85.2 g of gelatin A, Bloom 100, were added to 230 g of water and, after 
swelling for 30 minutes, dissolved by heating to 70.degree. C. Addition of 
42.8 g of fructose syrup (sugar content 70%, of which 95% fructose in dry 
matter) was followed by successive addition of 15 g of glycerol, 89.1 g of 
corn starch, 7.5 g of .beta.-alanine and 75.3 g of vitamin A acetate (2.19 
million IU/g, prepared from vitamin A acetate 2.9 million IU/g and 
stabilized with 100 mg of ethoxyquin and 14.5 mg of BHT per million IU of 
vitamin A). After addition of a further 170 g of water the mixture was 
emulsified by vigorous agitation at 60.degree. C. The emulsion was sprayed 
at 55.degree. C. and under from 5.5 to 6.5 bar through a single-component 
nozzle into a cloud of hydrophobic silica in a spray tower. The still 
moist product was dried in a fluidized bed dryer at room temperature to a 
residual moisture content of 5.2% and separated from the excess silica. 
The fructose content determined enzymatically was 9.0%. Subsequently 10 g 
of the resulting powder were heated in a rotating aluminum flask immersed 
in an oil bath at 120.degree. C. for 20 minutes (min). The resulting brown 
powder had a vitamin A content of 560,300 IU/g and a residual moisture 
content of 2.1%. The residual fructose content was found to be 2.4%. 
Alternatively, 10 g of the uncrosslinked powder were heated at 100.degree. 
C. for 24 min. The resulting brown powder was not dispersible in boiling 
water (particles remained unchanged ). 
EXAMPLES 2 TO 16 
The procedure of Example 1 was used to prepare emulsions with the 
ingredients indicated in the following Table, followed by spraying to give 
a powder which was dried and then heated at 120.degree. C. for 20 min. A 
vitamin A acetate containing 2.19 million IU/g which had been stabilized 
with 100 mg of ethoxyquin and 14.5 mg of BHT per million IU was used in 
all the experiments. Gelatin A Bloom 100 was used in all the Examples. The 
fructose syrup employed in the Examples was the fructose syrup described 
in detail in Example 1. 
The gelatin contents stated in the following Table are percentages of the 
weight of the dried powder. They were calculated taking account of the 
water contents in the auxiliaries (gelatin 12%; corn starch 13%, sugar 
30%) and of the residual water content and of the dusting with silica, 
which together amount to about 7% by weight. 
TABLE 1 
__________________________________________________________________________ 
Heat-treated product 
Ingredients of the emulsion Resi- 
Resid- 
Amino Ara- 
Sodium 
dual 
ual Vit. A 
Time.sup.5) 
Gela- 
com- 
Corn Gly- 
chis 
phy- 
mois- 
fruc- 
con- 
100/ 
Vit. A 
Sugar 
tin pound 
starch 
Water 
cerol 
oil 
tate 
ture 
tose 
tent 
110.degree. C. 
Ex. [g] [g] [g (%)] 
[g] [g] [g] [g] 
[g] 
[g] [%] 
[%] [IU/g] 
[min] 
__________________________________________________________________________ 
2 75.3 
42.8 
85.2 
7.5 89.1 
400 15 -- -- 2 0.3 562,400 
6/ 
fruc- 
(25) 
Ca .beta. 
tose alani- 
syrup nate 
3 75.5 
42.8 
85.2 
7.5 103 350 -- -- -- 2.5 
3.7 577,400 
39/10 
fruc- 
(25) 
lysine 
tose 
syrup 
4 75.3 
42.8 
136.4 
-- 60 400 -- -- -- 2.3 
6.4 568,900 
&gt;60/40 
comp. fruc- 
(40) 
tose 
syrup 
5 75.6 
42.3 
85.2 
7.5 66.2 
350 15 15.sup.1) 
3.sup.2) 
3.9 549,500 
invert 
(25) 
lysine 
sugar.sup.3) 
6 75.6 
42.3 
85.2 
9.6 63.8 
350 15 15.sup.1) 
3.sup.2) 
3.1 551,000 
invert 
(25) 
L- 
sugar.sup.3) 
lysine. 
HCl 
7.sup.4) 
50.2 
28.6 
56.8 
7.5 45.6 
250 10 10.sup.1) 
2.4.sup.2) 
2.7 603,000 
25/ 
furc- 
(25) 
L- 
tose lysine. 
syrup HCl 
8 75.3 
64.2 
85.2 
15 77.3 
350 -- -- -- 2.2 
3.7 554,600 
10/ 
fruc- 
(25) 
L- 
tose lysine 
syrup 
9 75.3 
85.6 
85.2 
30 42.7 
400 -- -- -- 5.2 
1.7 562,600 
8/ 
furc- 
(25) 
L- 
tose lysine 
syrup 
10 100.4 
112.7 
68.2 
4.0 123 400 20 -- -- 3.3 
6.7 553,000 
30/ 
invert 
(15) 
Ca .beta.- 
sugar.sup.3) 
alan- 
inate 
11 100.4 
112.7 
68.2 
20.0 
104 400 20 -- -- 3.8 
3.0 563,700 
11/ 
invert 
(15) 
Ca .beta.- 
sugar.sup.3) 
alani- 
nate 
12 75.3 
42.8 
85.2 
7.5 89.1 
400 15 -- -- 2.7 
2.8 525,400 
fruc- 
(25) 
gly- 
tose cine 
syrup 
13 75.3 
42.8 
85.2 
7.5 103 350 -- -- -- 2.5 
4.5 538,600 
30/ 
fruc- 
(25) 
L-.alpha.- 
tose ala- 
syrup nine 
14 75.3 
42.8 
85.2 
7.5 89.1 
410 15 -- -- 2.5 
4.5 570,300 
30/ 
fruc- 
(25) 
DL- 
tose meth- 
syrup ionine 
15 75.3 
42.8 
85.2 
7.5 103 350 -- -- -- 1.7 
2.2 563,000 
9/ 
fruc- 
(25) 
hexa- 
tose methy- 
syrup lene- 
dia- 
mine 
16 100 84.5 
90.9 
6.0 120.7 
400 20 -- -- 3.2 574,200 
28/8 
invert 
(20) 
3- 
sugar.sup.3) 
amino- 
pro- 
panol 
__________________________________________________________________________ 
.sup.1 Arachis oil was added immediately before additon of the vitamin A 
acetate. 
.sup.2 Sodium phytate was added immediately after addition of the corn 
starch. 
.sup.3) Proprietary name Isosweet supplied by Amylum, sugar content 70%, 
of which 51% dextrose and 42% fructose in dry matter. 
.sup.4) Before adding the vitamin A acetate, the mixture with all the 
other ingredients was adjusted to pH 8.7 with 25% strength NaOH. 
.sup.5) Minimum crosslinking time at which the product heated at 100 or 
110.degree. C. no longer forms a dispersion in boiling water. 
EXAMPLE 17 
The procedure of Example 1 was used to prepare an emulsion with the 
ingredients detailed below, followed by spraying to give a powder and 
drying. 
______________________________________ 
Vitamin A acetate 2.19 million IU/g 
52.4 g 
stabilized with 100 mg of ethoxyquin 
and 14.5 mg of BHT per million IU 
Vitamin D3 40 million IU/g 
0.55 g 
(dissolved in vitamin A acetate) 
Fructose syrup 29.8 g 
Gelatin A Bloom 100 59.3 g 
Ca .beta.-alaninate 5.2 g 
Corn starch 72.0 g 
Water 280.0 g 
______________________________________ 
The resulting product was heated at 120.degree. C. for 20 min. The residual 
moisture content was 4.1%, the residual fructose content was 2.4%, the 
vitamin A content was 558,200 IU/g and the vitamin D3 content was 109,000 
IU/g. 
EXAMPLE 18 
The procedure of Example 1 was used to prepare a canthaxanthin dispersion 
with the ingredients detailed below, followed by spraying to give a powder 
and drying. 
______________________________________ 
Canthaxanthin micronized 
37.0 g 
Ethoxyquin 11.0 g 
Ascorbyl palmitate 3.0 g 
Gelatin B Bloom 200 94.3 g 
Invert sugar.sup.3) 224.3 g 
Ca .beta.-alaninate 17.0 g 
Water 613.0 g 
______________________________________ 
The residual moisture content of the resulting powder was 7%. The 
enzymatically determined fructose content was 16.0% and the glucose 
content was 20.8%. 
The powder was heated at 120.degree. C. for 20 min. The residual moisture 
content of the heated product was 4.2%, and the residual fructose and 
glucose was found to be 11% and 4.6%. The canthaxanthin content of the 
powder was 12.2%. 
EXAMPLES 19-21 
99.9 g of gelatin A Bloom 100 were added to 230 g of water and, after 
swelling for 30 minutes, dissolved by heating to 70.degree. C. Addition of 
61.9 g of invert sugar (proprietary name Isosweet supplied by Amylum, 
sugar content 70%, of which 51% dextrose and 42% fructose in dry matter) 
was followed by successive addition of the amounts, indicated in Table 2, 
of glycerol, corn starch and vitamin A acetate (2.19 million IU/g, 
prepared from vitamin A acetate 2.9 million IU/g and stabilized with 100 
mg of ethoxyquin and 14.5 mg of BHT per million IU of vitamin A). After 
addition of a further 140 g of water and the amount, which is evident from 
Table 2, of a 10% strength aqueous NaOH solution, the mixture was adjusted 
to the pH indicated in Table 2 and emulsified by stirring vigorously at 
60.degree. C. 
The emulsion was sprayed at 55.degree. C. and under from 5.5 to 6.5 bar 
through a single-component nozzle into a cloud of hydrophobic silica in a 
spray tower. The still moist product was dried in a fluidized bed dryer at 
room temperature to a residue of moisture content of 5.2% and separated 
from the excess silica. Subsequently 10 g of the resulting powder were 
heated in a rotating aluminum flask immersed in an oil bath at 110.degree. 
C. for the time indicated in Table 2 (minimum crosslinking time after 
which the product heated at 110.degree. C. no longer disperses in boiling 
water ). 
The resulting products were subjected to the premix stress test (40.degree. 
C./70% relative humidity), which is described hereinbefore, for six weeks 
and then tested for their vitamin A content. 
Comparison of the results for Examples 19 and 21 with the Comparative 
Example 20 (without addition of base to the emulsion) shows that a 
distinct increase in stability of the product, and a reduction in the 
minimum crosslinking time, can be achieved by increasing the pH of the 
spray emulsion with NaOH. 
TABLE 2 
__________________________________________________________________________ 
Heat-treated product 
Ingredients of the emulsion Vit. A 
Gela- Corn Gly- 
con- 
Vit. A 
Sugar 
tin NaOH starch 
Water 
cerol 
tent 
Time at 
Retention after 
Ex. 
[g] [g] [g (%)] 
[g (pH)] 
[g] [g] [g] 
[IU/g] 
110.degree. C. 
6 weeks 
__________________________________________________________________________ 
19 75.3 
61.9 
99.9 (30) 
13(8) 
57.9 
370 14.6 
571.800 
18 80.7 
20* 
75.3 
61.9 
99.9 (30) 
-(5.3) 
74.9 
370 -- 576.000 
45 74 
21 75.3 
61.9 
99.9 (30) 
19 (9.0) 
74.9 
370 -- 558.200 
26 83 
__________________________________________________________________________ 
*Comparative Example 
EXAMPLE 22 
In the same way as described for Examples 19 to 21, an emulsion was 
prepared with the composition indicated for Comparative Example 20 and 
consequently portions were adjusted to the pH evident from Table 3 using 
the base evident from Table 3, and the minimum crosslinking time at 
120.degree. C. was determined for the dry powders prepared as in Examples 
19-21. 
TABLE 3 
______________________________________ 
Minimum 
pH of the crosslinking 
Composition of spray time at 120.degree. C. 
the emulsion 
Added base emulsion [min] 
______________________________________ 
a) as Example 20 
-- 5.3 26 
b) as Example 20 
NaOH 9.0 11 
c) as Example 20 
KOH 9.0 10 
d) as Example 20 
MgO 9.0 14 
e) as Example 20 
Ca(OH).sub.2 
9.0 11 
______________________________________ 
Increasing the pH of the emulsion with various bases before the spraying 
leads to a markedly reduced minimum crosslinking time for the dry powders.