HK1059733A - Aqeous solution of ascorbic acid - Google Patents

Description

The invention relates to an aqueous solution of ascorbic acid.

The technical use, particularly in personal care products and foodstuffs, and prophylactic use of the reducing agent ascorbic acid is often hampered by the fact that ascorbic acid is not sufficiently stable in aqueous solution, so that after about 30 days only about 70% of the ascorbic acid to be added is still present in an aqueous ascorbic acid solution.

The resistance has been improved by using a derivative of ascorbic acid instead, such as sodium ascorbic phosphate or ascorbyl palmitate, which is almost constant in aqueous solution for a long time, but is several times more expensive than pure ascorbic acid.

European patent 660676 describes a composition consisting of 0.1-2.0% of a soluble oil component, preferably a colouring carotenoid, 2-20% of an emulsifier with an HLB value of 10-18 and 0.1-1.0% of an antioxidant. The emulsifier can be polysorbate 40 or 60, as an antioxidant is recommended among others ascorbic acid. This is to produce clear and stable beverages for health care.

The purpose of the invention is to provide ascorbic acid in liquid, water and fat soluble and encapsulable form (e.g. gelatine capsule) which is stable for many months and is present in high concentration.

This problem is solved by the invention that an aqueous solution of ascorbic acid contains an excess of an emulsifier with an HLB value of 9-18 such as a polysorbate, preferably polysorbate 80. The solution is clear and almost gelatinous at room temperature, is free of turbidity, is water-dilutable and can be easily and homogeneously mixed with aqueous or fatty final products from the cosmetics or food sector at about 35°C without further processing. The ascorbic acid content of the solution of the invention, which can be up to about 20%, is maintained for at least half a year without any loss of activity. The polysorbic residue is approximately 60% of the water content. The ascorbic acid content is significantly increased by the addition of these products (e.g. alkaloids, alkaloids, alkaloids, alkaloids) to the food and to the hair (e.g. alkaloids), and the fact that the product can be easily incorporated into food and food (e.g. alkaloids) and food products (e.g. alkaloids) is due to the fact that the ascorbic acid content of the product of the invention, which can be up to about 20%, is maintained for at least half a year.

The ascorbic acid is present in the micellated solubilizer. An electron microscopic examination of a 10% ascorbic acid solubilizer at a dilution of 1:1000 shows a micellar diameter of about 100 nm. Since the emulsifier shell of the micelles only releases the enclosed ascorbic acid with a delay, the antioxidant effect of the solubilizer of the invention in the above-mentioned products in combination with soluble mixed tocopherols remains effective for longer than when ascorbyl palmitate, one of the ascorbic acid derivatives mentioned at the beginning, is added.

From the nutritional point of view, the micellation of ascorbic acid by the emulsifier prevents the ascorbic acid from acting and being consumed in the middle digestive tract, i.e. the stomach and duodenum, when the solubiliser of the invention is administered orally.

In a particularly preferred formulation of the invention, the ascorbic acid solubilisate contains an addition of tocopherol, in particular to a mixed tocopherol. By adding this ascorbic acid-tocopherol solubilisate to organic oils, e.g. vegetable oils such as sunflower oil, distil oil, linseed oil and the like, their shelf life can be significantly improved. As tocopherol, either pure α-tocopherol or a mixture of α-, β-, γ- and δ-tocopherol is considered as particularly preferred. A mixed tocopherol containing approximately 8,0 to 20,0 per cent α-tocopherol, approximately 1,5 to 4,5 per cent β-tocopherol, approximately 55,0 to 27,0 per cent γ-tocopherol and approximately 15,0 to 70,0 per cent δ-tocopherol is recommended.

When an octadecatic acid and/or an octadecatic acid, e.g. in the form of α-linolenic acid, γ-linolenic acid, linoleic acid or oleic acid, is added to the solution of the invention, the viscosity of the solution is reduced. It is clear, viscous, undurbed at room temperature, water-soluble, or miscible with water and/or fatty foods, cosmetics and pharmaceuticals without further processing. The polysorbate content of the solution of the invention serves as a kind of retardant for the conservative property of ascorbic acid for the generally easily oxidisable components of salts and polysorbic acid. The desired protective function can therefore be maintained for a period of time of up to about 20% of the solution and approximately 15% of the ascorbic acid can be extracted. The ascorbic acid can be preserved for about 75% of the solution and the desired protective function can be maintained for about 20% of the solution.

If the water content of the solution of the invention is reduced to about 5 to about 7 parts per cent and the polysorbate content is increased accordingly, the viscous solution at room temperature can also be mixed with active substances, which are then filled in gelatine capsules or non-gellatine capsules.

A method for preparing the solution of the invention involves adding to an aqueous ascorbic acid solution an emulsifier with an HLB value of about 9 to about 18, e.g. a polysorbate, preferably polysorbate 80, and briefly heating the mixture by stirring it to clarity and homogeneity. The micelles formed in the solution, with a diameter of about 100 nm, have a double-walled shell of radially oriented polysorbate molecules, the polysorbate molecules of the inner shell with their hydrophilic sections being directed towards the ascorbic acid solution and the hydrophilic sections of the polysorbate molecule of the outer shell being directed towards the water. This solution is dipped in water and can be dissolved without further processing.

The stability of the micelles is improved by adding a light natural oil, such as mustard oil, consisting mainly of triglycerides, to the emulsifier in the further development of the aqueous ascorbic acid solution of the invention.

It is appropriate to add to the solution, after heating it slightly at about 50°C, by stirring, an octadecatic acid and/or an octadecatic acid, e.g. in the form of α-linolenic acid, γ-linolenic acid, linoleic acid or oleic acid, before adding polysorbate. For the filling of capsules, the capsules may be gelatinous or gelatin-free, it is advantageous to dissolve ascorbic acid in the same amount of aqua, to add to the solution the same to the maximum amount of ascorbic acid in fatty acids at low heat, and to add about two to about three times the amount of polysorbic acid at 80°C and to heat and stir the mixture to about 80°C.

The following examples illustrate the invention.

Example 1

20 g ascorbic acid are completely dissolved in 20 g of distilled, degassed water. The dissolution process can be accelerated by heating the water to about 45 °C. Then 60 g polysorbate 80 are added to the solution by stirring and heating to about 80 °C. It is stirred until the solubilizer is clear and homogeneous, appears clear and almost solid at room temperature, is easily diluted in water and can be added to the preserved compositions or to food, beverages, cosmetics and pharmaceuticals without further processing.

For a low-concentration solubilizer, dissolve 10 g of ascorbic acid in 10 g of aqua dest and add 80 g of polysorbate 80, the procedure being as follows. The 10% ascorbic acid solubilizer obtained was diluted to 11 000 by water and then taken under an electron microscope, as shown in Figure 1.

Example 2

As in example 1, dissolve 10% w/w ascorbic acid (relative to the total amount of ascorbic acid solubilisate = 100%) in 10% w/w aqua dest and add to this aqueous solution 70% w/w polysorbate 80 together with 10% w/w of a light vegetable oil such as mustard oil or linseed oil.

Reducing the ascorbic acid content to about 7% by weight and the water content to about 7% by weight and increasing the other proportions of the solubiliser accordingly, it can be used particularly well as a preservative for active substances to be encapsulated as retardants because of its relatively low water content.

Example 3

10 g of ascorbic acid are dissolved in 10 g of aqua and 20 g of distillate oil are added to the solution. To this mixture, 110 g of polysorbate 80 are added and the mixture is heated at about 100 °C until it is free of water, i.e. until the end of cooking. After cooling to room temperature, the solvent contains a 6,5% ascorbic acid solubilite, which is well below 5% vol, and which is soluble in water as well as in fats and oils. An examination of the ascorbic acid content of the solution by an independent chemical laboratory at the time of preparation of the solution and more than five months later showed a loss of ascorbic acid of only about 3% during this time.

Example 4

From the solubilisate, starting from example 2, a mixed tocopherol solubilisate is added, which is obtained as follows: 10 wt% mixed tocopherol (based on the mixed tocopherol solubilisate = 100Gew%) is mixed with 90 wt% polysorbate 20 by stirring, the mixing process is accelerated by heating to about 60°C. The stirring is continued until clarity is achieved and the solubilisate is easily soluble in water. For the hole tocopherol mixture, a composition of 91 mg/g mixed tocopherol α-tocopherol, 21 mg/g tocopherol β, 60 mg/g tocopherol γ and 20 mg/g tocopherol δ is recommended.

Then, in accordance with example 2, first alternative, about 3 parts by weight of the solubiliser are mixed with about 7 parts by weight of the mixed tocopherol solubiliser, with a slight heating to about 50°C to speed up the mixing process. The stirring in the heat is carried out until a homogeneous and clear solubiliser is obtained. 1 g of this product contains about 70 mg of mixed tocopherol and about 30 mg of ascorbic acid. This solubiliser can be used as an effective antioxidant to improve the shelf life of food colours, oils, cosmetics, pharmaceuticals and the like.

Comparative tests have shown that this solubilisate can be incorporated directly into the final product, regardless of its properties (hydrophilic or hydrophobic), without intermediate steps in production, and offers better protection against oxidation than the same amount of ascorbic acid from an ascorbic acid derivative such as ascorbyl palmitate.

The nutritional benefit of the solubiliser is that the stomach acid-stable mycelium ensures that ascorbic acid (vitamin C) and vitamin E (if α-tocopherol is used) reach the small intestine without loss for absorption.

Example 5

20 wt% α-tocopherol is mixed with 80 wt% polysorbate 20 by stirring, if necessary at a temperature of about 50°C, until it is clear and homogeneous. Finally, 10 wt% of a concentrate containing about 30% β-carotene (available from La Roche) is mixed with 90 wt% polysorbate 80 in an appropriate manner to form a red-brown, transparent solubilisate which is clearly soluble in tempered water. Then, 85 W/o of the ascorbic acid solubilisate is mixed with 10 W/o of the superior α-tocopherol solubilisate and 2 W/o of the superior retinol solubilisate and finally 3 W/o of the β-carotene solubilisate at suitable temperatures by stirring, as in Example 2, first alternative, until a homogeneous and transparent mixed solubilisate is obtained.

When administered in water and/or clear fruit or fruit juices, the vitamin solubilisate of the invention gives a stable and clear solution, unlike emulsions or liposomes. The product micelles are acid-stable. The absorption of the fat-soluble substances contained in the micelles, such as vitamin A, vitamin E and β-carotene, takes place in the small intestine without the involvement of bile salts and enzymes. Therefore, the active substances mentioned in the micellated form are more readily bioavailable.

1 gram of vitamin soluble extract of the above composition incorporated in food or incorporated in capsules covers the human daily requirement for vitamins A, C, E and β-carotene. The numerical composition of vitamin soluble extract indicated above is based on this fact. This indicates that the daily requirement for vitamin C is substantially higher than that for other vitamins. However, it is within the scope of the invention to choose other compositions for vitamin soluble extract and/or to abstain from one or the other vitamin altogether if the intended use makes the presence of a particular vitamin in vitamin soluble extract unnecessary or desirable.

Figures 2, 3 and 4 show the mean micelle radii of α-tocopherol solubilisate, β-carotene solubilisate and retinol solubilisate. As can be seen, the mean micelle radii are at 10 nm and for retinol solubilisate even at only about 8 nm. The measurements were made using field-fluid fractionation by Wyatt Technologies. Figure 5 shows an electron microscopic uptake of a vitamin A micron and Figure 6 an electron microscopic uptake of vitamin E micron; the samples were a water dilution of 1 × 1000 of the solubilisates described above.

Claims (18)

1. Aqueous solution of ascorbic acid containing an excess of an emulsifier with an HLB value of approximately 9 to approximately 18, e.g. a polysorbate.
2. Solution according to claim 1 with a polysorbate content of 80.
3. Solution according to claim 1 or 2 containing an octadecatic acid and/or octadecenoic acid, e.g. in the form of α-linolenic acid, γ-linolenic acid, linoleic acid or oleic acid.
4. Solution according to claim 1 or 2 with an ascorbic acid content of about 20% by weight and a polysorbate content of about 60% by weight.
5. Solution according to claim 3 with an ascorbic acid content of approximately 5% to 15% by weight, a polysorbate content of approximately 75% to 60% by weight and an octadecataric acid and/or octadecenoic acid content of approximately 10% to 20% by weight.
6. Solution with one of the above claims and a content of mixed tocopherol.
7. Solution according to claim 6 with a polysorbate content of 20.
8. Solution according to claim 6 or 7 containing about 8 to about 20% w/w α-tocopherol, about 1,5 to about 4,5% w/w β-tocopherol, about 55 to about 70% w/w γ-tocopherol and about 15 to about 27% w/w δ-tocopherol.
9. Solution containing vitamin A and/or vitamin E and/or β-carotene according to one of the above claims.
10. A process for the preparation of a solution according to one of the above claims, characterised by the addition of a polysorbate to an aqueous ascorbic acid solution and, where appropriate, by stirring the mixture to clarity under light heat.
11. The method described in claim 10 is characterised by the addition of polysorbate 80 to the solution.
12. The method described in claim 10 or 11 is characterised by the addition of octadecatic acid and/or octadecenoic acid, e.g. in the form of α-linolenic acid, γ-linolenic acid, linoleic acid or oleic acid, to the solution after a light heating to about 50 °C by stirring before the addition of polysorbate.
13. Method according to one of claims 10 to 12, whereby a quantity of ascorbic acid is dissolved in the same quantity of aqua, twice the quantity of ascorbic acid is added to the solution of light triglyceride-containing fatty acids under light heating and about two to about three times the quantity of polysorbate 80 is added and the mixture is heated to about 80°C under stirring.
14. The method described in claim 10 or claim 11 is characterised by the addition to the solution of a mixture of α-tocopherol and polysorbate 20, which has been stirred to clarity, if necessary, under light heat.
15. Process according to one of claims 10, 11 or 14 characterised by the addition of a mixture of retinol and polysorbate 80 agitated to clarity.
16. Process according to one of claims 10, 11, 14 or 15 characterised by the addition of a mixture of β-carotene and polysorbate 80 agitated to clarity.
17. Use of a solution according to claims 1 to 9 as an additive in skin and hair care products, food, pharmaceuticals and nutritional solutions for cell and bacterial cultures or algal cultures.
18. Use as claimed in claim 17 in gelatine capsules and/or gelatine-free capsules.