CA2150399C

CA2150399C - Incorporation of a water-soluble active principle in a lipid

Info

Publication number: CA2150399C
Application number: CA002150399A
Authority: CA
Inventors: Raymond Bertholet
Original assignee: Societe des Produits Nestle SA
Current assignee: Societe des Produits Nestle SA
Priority date: 1994-06-17
Filing date: 1995-05-29
Publication date: 2006-01-24
Anticipated expiration: 2015-05-29
Also published as: AU2030595A; FI952871A; AU704264B2; DE69429719T2; JPH0853690A; ATE212192T1; ES2170079T3; FI952871A0; DE69429719D1; NO952412D0; JP3715345B2; EP0687419A1; EP0687419B1; NO952412L; CA2150399A1

Abstract

To incorporate a water-soluble active principle in a stable lipidic phase, the water-soluble active principle is added with stirring in the presence of water to a fat containing a lecithin fraction low in phosphatidyl choline and the heterogeneous mixture obtained is dried to form a homogeneous micellar phase.

Description

- r -'~~~~~'0300 This invention relates to a process for incorpora-ting a water-soluble active principle in a lipid and, more particularly, for stabilizing a water-soluble antioxidant in a lipidic phase.
The majority of oils and certain fats used in food, cosmetic and pharmaceutical products are rich in poly-unsaturated fatty acids and, because of this, are par-ticularly sensitive to oxidation. Their stability can be improved by the addition of synthetic antioxidants such as, for example, BHA (butyl hydroxyanisole), BHT (butyl hydroxytoluene) or TBHQ (tert.butyl hydroquinone).
Unfortunately, the harmlessness of these compounds is questionable.
Attempts have been made to replace them with natural antioxidant compounds of the fat-soluble type such as, for example, the tocopherols or ascorbyl palmitate or of the water-soluble type such as, for example, ascorbic acid, vegetable extracts, organic acids or amino acids.
In the case of the water-soluble compounds, an emulsi fier, such as a phospholipid for example, has to be used for incorporating the water-soluble antioxidants in the oils in the form of micelles.
By virtue of their structure, the phospholipids are capable of creating associations with certain water soluble compounds to form micelles which, for their part, are fat-soluble.
The incorporation of vitamin C or other water-soluble compounds in oils using phospholipids is known, for example, from EP-A-0 326 829. Unfortunately, this known process uses an organic solvent, for example ethanol, which promotes the formation of a single phase in view of its hydrophilic and lipophilic properties. In addition, the process in question - which uses an unfrac-tionated Soya lecithin - is attended by the disadvantage that problems of colour, odour and flocculation in storage cannot be avoided.
According to U8-A-5,084,289, inverse micelles, i.e.
micelles in which the continuous phase is the lipophilic phase, are formed by dissolving in an oil a phospholipid and then a small quantity of an aqueous solution containing a water soluble antioxidant, for example vitamin C, in a high concentration. The mixture is stirred to form inverse micelles, a single phase thus being obtained. The small quantity of aqueous phase relative to the lipidic phase makes homogenization difficult or even virtually impossible on a large scale. In addition, it is only possible by this process to incorporate substances highly soluble irx wager, for example vitamin C, and not sparingly water-soluble substances such as, for example, ethylene dinitrogetraacetic acid (EDTA). Finally, this process does not avoid the appearance of undesirable colours and odours in storage because the lecithin is not fractionated.
It has now surprisingly been found that these disadvantages can be completely eliminated by using a lecithin fraction substantially free from phosphatidyl choline.
According to one aspect: o.f the present invention there is provided a process for incorporating a water-soluble active principle in a fat in the presence of lecithin, characterized in that the lecithin is treated to produce a lecithin fraction substantially free from phosphatidyl choline, an aqueous solution of the water-soluble active principle is incorporated in the mixture of this fraction and fat in liquid form with vigorous stirring in a quantity sufficient to hydrate the lecithin fraction to farm a heterogeneous mixture and the mixture obtained is dried and thus become homogenous.
According to a further aspect of the present invention there is provided a process for incorporating a water-soluble active principle in a fat which comprises treating lecithin to produce a lecithin fraction which is substantially free from phosphatidyl choline, forming a mixture of the lecithin 2a fraction and liquid fat, adding a water soluble active principle, with vigorous stirring, in an amount sufficient to hydrate the lecithin fraction and form a heterageneous mixture and drying the heterogeneous mixture to form a homogeneous composition.
According to another aspect of the present invention there is provided a process for incorporating a water--soluble active principle in a fat which comprises treating phospholipids to produce a phospholipid fraction which is substantially free from phosphatidyl choline, forming a mixture of the phospholipid fraction and liquid fat, adding a water soluble active principle to a quantity of water with agitation for a sufficient period of time of_ about 10 to 30 minutes at a temperature of about 60°C. to about 80°C. and under an atmosphere sufficient to incorporate th.e water-soluble active principle into the water, adding a sufficient amount of the water to hydrate the phospholipid fraction to hydrate it and form a heterogeneous mixture, and drying the heterogeneous mixture to form a homogeneous composition.
According to a still further aspect of the present invention there is provided a food, cosmetic or pharmaceutical product containing a homogeneous composition prepared by a process as defined above.

In the context of the present invention, a "lecithin fraction substantially free from phosphatidyl choline" is understood to be a fraction obtained from commercial lecithin, for example Soya, by a treatment which enables the phosphatidyl choline to be separated from the other constituents, such as phosphatidyl ethanolamine, phospha-tidyl inositol and phosphatidic acid, hereinafter refer-red to as "other PLS" (other phospholipids).
In a first embodiment, the commercial lecithin is treated in solution in the oil with a bleaching earth as adsorbent, after which the oil thus treated is separated.
In a second embodiment, which is preferred, the lecithin is treated in solution in a mixture of organic solvents by liquid chromatography in a column of silica gel in known manner and the fraction containing the other PLS, which is also freed from most of the triglycerides, is collected.
The water-soluble active principles envisaged in accordance with the invention are, for example, cosmetic or dermatological agents or water-soluble antioxidants.
They include, for example, conventional antioxidants, for example vitamin C, vegetable extracts, for example rosemary, green tea, organic acids, for example hydroxy acids, such as citric acid, phenolic acids, for example caffeic, quinic and chlorogenic acids, caffeine, amino acids, phenyl indanes and sequestering agents, for example citrates or EDTA.
The fat to be protected against oxidation is rich in unsaturated fatty acids, more particularly polyunsatura ted fatty acids. The fat may be a vegetable oil, for example sunflower oil, wheat germ oil, grapeseed oil, corn oil, safflower oil, olive oil, evening primrose oil, borage oil and blackcurrant seed oil, or an animal oil, for example chicken fat, butter oil, a marine animal oil, more particularly fish oil.

~~ ~o~.oo The incorporation of the water-soluble active principle takes place with vigorous stirring at a temper-ature above 60°C and preferably at a temperature of the order of 80°C. The water-soluble active principle may be introduced in the form of an aqueous solution or, alter-natively, in dry form, in which case water is subsequent-ly added. The quantity of water in the mixture should be sufficient to hydrate the quantity of lecithin fraction which it contains. It represents 2 to 8% by weight of the mixture and, preferably, approximately 5% thereof.
This operation takes place over a period of 10 to 30 minutes in the absence of air, for example in a nitrogen atmosphere, which results in the formation of a hetero-geneous mixture.
The water is then eliminated from the heterogeneous mixture by heating in vacuo, preferably to 60 to 90°C and advantageously to 60 to 70°C under a vacuum of 0.5 to 35 mbar. A homogeneous and stable micellar phase is formed.
The invention is illustrated by the following Examples in which parts and percentages are by weight, unless otherwise indicated.
Example 1 A refined Soya lecithin low in heavy metals (Top cithin 200~) and containing 60% of phospholipids (refer red to hereinafter as PLS) is dissolved under nitrogen in a sunflower oil (SFO).
The solution is then treated with a bleaching earth (Tonsil Optimum FF~) for 30 minutes at 85 to 90°C, under a pressure of 35 mbar and in the presence of a foam inhibitor (Rhodosil 70414~), the quantity of adsorbent corresponding to four times the quantity of phospho-lipids, after which the solution is separated from the adsorbent by filtration.
The quantities shown in Table 1 below of vitamin C

~~ ~~39~
and EDTA in solid form and then 5% of demineralized water are subsequently added to the solution. After vigorous stirring under nitrogen for 15 minutes at 80°C, a hetero-geneous mixture is obtained and is then dried for 30 minutes at 80-90°C under a pressure of 35 mbar and then 0.5 mbar and filtered. A homogeneous micellar phase is obtained.
The stabilized oil (1a) is evaluated by comparison with the same, unstabilized oil (lb) and with an oil stabilized with a commercial lecithin which has not been treated with bleaching earth (1c):
- From the point of view of their stability to oxidation as measured by the Rancimat~ accelerated oxidation test at 110°C. The induction times obtained, expressed in h, represent the OSI (oil stability index) values.
- From the point of view of their stability in storage at 15°C by visual and olfactory assessment.
The results obtained are set out in Table 1 below:
Table 1 Test PL Vit. EDTA Treat- OSI, Colour C

mg/kg mg/kg mg/kg ment 110C,h 1a 10000 1000 200 Yes 19.5 Yellow lb ---- ---- ---- ---- 5 Light yellow 1c 10000 1000 200 No 17.5 Orange-yellow It can be seen that the treatment of lecithin with a bleaching earth improves its colour and increases its stability to oxidation.
Examples 2-10 SFO is stabilized in the same way as in Example 1 using vitamin C in conjunction with various sequestering agents in various quantities. The OSI values of unstabi-~~~0~9~

lized SFO (2a) and SFO containing the PL fraction treated with the adsorbent (2b) are measured by way of compari-son.
The protection factor (PF), which corresponds to the quotient:
PF = OSI of the stabilized oil/OSI of the unstabilized oil (this quotient represents the increase in the induc-tion time), is calculated from the OSI values.
The results are set out in Table 2 below:
Table 2 Exam- PL Vit.C Segues- SA OSI PF Stability ple mg/kg mg/kg tram, mg/kg 110C, at 15C

SA h after 5d 2a ---- ---- ---- ---- 5 1 Clear 2b 5000 ---- ---- ---- 5.7 1.14 Clear 2 5000 1000 ---- ---- 19 3.8 Slightly cloudy 3 5000 1000 EDTA 100 22.5 4.5 Slightly cloudy 4 5000 1000 EDTA 200 22 4.4 Clear 5000 1000 EDTA 400 20 4 Clear 6 5000 1000 EDTA 200 21 4.2 Slightly Na2 cloudy 7 5000 1000 Citric 200 17 3.4 Slightly acid cloudy 8 5000 1000 Citric 200 20.5 4.1 Slightly acid cloudy Na3 9 5000 1000 Citric 400 16 3.2 Clear acid Na3 5000 1000 EDTA 200 21.8 4.36 Slightly citric cloudy acid Na3 ~~ ~fl39a It can be seen that the use of PL on its own is not sufficient to stabilize the oil (2b compared with 2a).
Examples 11-15 Following the procedure of Example 1, SFO stabilized with various ratios of vit.C to PL is evaluated for stability in storage, OSI and PF. The results are set out in Table 3 below by comparison with the unprotected oil (lla) and with the same oil to which 1.66% of a ternary mixture of vit.C, PL and vit.E in quantities of 1000 mg/kg vit.C, 4500 mg/kg PL and 500 mg/kg vit.E is added (llb).
Table 3 Exam-PL Vit.C EDTA Vit.C/ OSI PF Stability ple mg/kg mg/kg mg/kg PLx100 110C, at 15C

h after 5d lla ---- ---- ---- ---- 5 1 Clear llb 4500 1000 ---- 22 15.8 3.16 Slightly +500 cloudy mg/kg vit.E

11 2500 1000 200 40 14.7 2.94 S1lght1y cloudy 12 5000 1000 200 20 22 4.4 Slightly cloudy 13 6600 1000 200 15 20.8 4.16 Slightly cloudy 14 7500 1000 200 13.3 20 4 Clear 15 10000 1000 200 10 20 4 Clear It can be seen that the use of a ternary mixture comprising vit.E does not improve the stability of the oil or its antioxidant properties in relation to the use of a mixture of PL and vit.C (11b compared with 11-15).
Accordingly, it may be concluded that the synergism between vit.C and vit.E already occurs with the vit.E

naturally present in SFO (corresponding to 760 mg/kg).
Accordingly, for vegetable oils naturally containing vit.E, the addition of more vit.E is not beneficial.
The stabilized oils were stored for 1 month at 15°C.
It was found that the oils stabilized with a ratio of vit.C to PL of greater than 13% became cloudy during that period. Accordingly, this ratio is preferably less than or equal to 13% to ensure optimal stability of the oil.
Examples 16-19 Following the procedure of Example 1, SFO stabilized with various quantities of vit.C (the ratio of vit.C to PL being constant) was evaluated for stability in stor-age, OSI and PF. The results obtained are set out in Table 4 below by comparison with the unprotected oil (16a).
Table 4 Exam-PL Vit.C EDTA Vit.C/ OSI PF Stability ple mg/kg mg/kg mg/kg PLx100 110C, at 15C

h after 30d 16a ---- ---- ---- ---- 5 1 Clear 16 2500 250 200 10 12.3 2.4 Clear 17 5000 500 200 10 16 3.2 Clear 18 7500 750 200 10 18 3.6 Clear 19 10000 1000 200 10 20 4 Clear Examples 20-24 Following the procedure of Example 1 to stabilize blackcurrant seed oil (BCSO), BCSO stabilized with a constant ratio of vit.C to PL is evaluated for stability in storage, OSI and PF. The results are set out in Table below by comparison with the unprotected oil (20a) and with the same oil to which 1.66% of a ternary mixture of vit.C, PL and vit.E in quantities of 1000 mg/kg vit.C, 4500 mg/kg PL and 500 mg/kg vit.E (20b) has been added.

Table 5 Exam-PL Vit.C EDTA Vit.E Vit.C/ OSI PF Stability ple mg/kg mg/kg mg/kg mg/kg PL x 100C, at 15C

100 h after 20d 20a ---- ---- ---- ---- ---- 4 1 Clear 20b 4500 1000 ---- 500 22 17.5 4.38 Slightly cloudy 20 10000 1000 ---- ---- 10 19.8 4.95 Clear 21 10000 1000 ---- 500 10 17.6 4.4 Clear 22 10000 1000 400 ---- 10 24 6 Clear 23 10000 1000 400 500 10 20.2 5.05 Clear 24 5000 500 200 ---- 10 17.2 4.3 Clear The results confirm those obtained with SFO (Ex-amples 11 to 15), namely that the addition of vit.E does not improve the stability of BCSO to oxidation but would actually seem to have a pro-oxidizing effect in a vege-table oil naturally containing around 750 ppm of vit.E
(Example 22 compared with 23).
Example 25 Following the procedure of Example 1 to stabilize chicken fat free from vit. E, the chicken fat is evaluated for OSI, PF and colour with and without added vit.E by comparison with the unprotected fat. The results ob-tained are set out in Table 6 below.
Table 6 PL Vit.C Vit.E EDTA OSI PF Colour after mg/kg mg/kg mg/kg mg/kg 120C,h Rancimat ---- ---- ---- ---- 2 1 Yellow 5000 500 ---- ---- 7.3 3.65 Yellow 5000 500 250 ---- 16.5 8.25 Orange 5000 500 ---- 100 10.5 5.25 Yellow 5000 500 250 100 19.3 9.65 Yellow ~~~o~oo The above results confirm that the synergistic effect between vit.C and vit.E exists when the fat to. be pro-tected does not naturally contain vit.E.
Example 26 A soya lecithin free from PC (other PLS fraction), which has been obtained as second fraction by liquid chromatography in a column of silica gel using a mixture of hexane, 2-propanol and water in a ratio of 1:1:0.1, is dissolved in SFO. A first fraction rich in phosphatidyl choline (PC fraction) is also collected.
Quantities of 10,000 mg/kg of each lecithin fraction, 1000 mg/kg of vit.C and 200 mg/kg of EDTA in solid form and then 5% of demineralized water are added to the oil. After vigorous stirring under nitrogen for 15 minutes at 20°C, a heterogeneous mixture is obtained and is dried for 30 minutes at 80 to 90°C under a pressure of 35 mbar and then 0.5 mbar. Filtration gives a homogeneous micellar phase in the case of the oil stabilized with the other PLS fraction.
By contrast, the PC fraction could not be dissolved in oil.
The OSI is then evaluated. The results are set out in Table 7 below.
Table 7 Phospholipids OSI 110°C Remarks PC Fraction ---- The fraction could not be dissolved in the oil Other PLS fraction 21 The fraction dissolves in the oil which is perfectly clear Examples 27-31 SFO is stabilized with various water-soluble antioxidant active principles in the same way as de-scribed in Example 26. The results are set out in Table 8 below. SFO with no additive (27a) was evaluated for ~~~~J~

comparison.
The phenyl indanes were obtained from coffee by the extraction process according to European Patent Application No.94109355.1 filed on 17.06.1994 under the title "Phenyl indanes, a process for their production and their uses".
Table 8 Example PL Active AP EDTA OSI PF

mg/kg principle mg/kg mg/kg 110C,h (AP) 27a ____ -___ ____ ____ 5 1 27 10000 L-histidine 1000 200 11.5 2.3 28 10000 L-cysteine 1000 200 12 2.4 29 10000 Rosemary 1000 200 14 28 extract 30 10000 Green tea 1000 200 12 2.4 extract 31 10000 phenyl 500 ---- 30.5 6.1 indanes Examples 32-33 The procedure described in Example 1 up to hydration of the PLS is used to stabilize an SFO. The drying step is carried out at various temperatures. The antioxidant properties and the colour of the stabilized oils are evaluated by comparison with the unstabilized oil (32a).
The results are set out in Table 9 below.

___ __~3 . _ Table 9 Exam- Drying PL Vit.C EDTA OSI PF Colour ple temper- without mg/kg mg/kg 110C, measurement ature PC h Lovibond 5.25"

Y R

32a ---- ---- ---- ---- 5 1 8.4 1.3 32 80- 10000 1000 400 21 4.2 43 4.8 33 60- 10000 1000 400 22.8 4.56 18.5 2.7 It can be seen that the colour is less intense where drying is carried out at a lower temperature.

Claims

1. A process for incorporating a water-soluble active principle in a fat in the presence of lecithin, characterized in that the lecithin is treated to produce a lecithin fraction substantially free from phosphatidyl choline, an aqueous solution of the water-soluble active principle is incorporated in the mixture of this fraction and fat in liquid form with vigorous stirring in a quantity sufficient to hydrate the lecithin fraction to form a heterogeneous mixture and the mixture obtained is dried and thus become homogenous.

2. A process for incorporating a water-soluble active principle in a fat which comprises treating lecithin to produce a lecithin fraction which is substantially free from phosphatidyl choline, forming a mixture of the lecithin fraction and liquid fat, adding a water soluble active principle, with vigorous stirring, in an amount sufficient to hydrate the lecithin fraction and form a heterogeneous mixture and drying the heterogeneous mixture to form a homogeneous composition.

3. A process as claimed in claim 1 or 2, wherein the lecithin is treated by forming an oil solution with a bleaching earth as adsorbent, after which the oil thus treated is separated.

4. A process as claimed in claim 1 or 2, wherein the lecithin is treated in solution in a solvent mixture by liquid column chromatography and the fraction containing phospholipids other than phosphatidyl choline, which is also substantially free from triglycerides, is collected.

5. A process as claimed in claim 1 or 2, wherein the water-soluble active principle is a cosmetic compound or dermatological agent or a water-soluble antioxidant.

6. A process as claimed in claim 1 or 2, wherein the water-soluble active principle is a vegetable extract, an organic acid, an amino acid or a sequestering agent.

7. A process as claimed in claim 1 or 2, wherein the water-soluble active principle is vitamin C.

8. A process as claimed in claim 1 or 2, wherein the liquid fat is rich in unsaturated fatty acids.

9. A process as claimed in claim 1 or 2, wherein the liquid fat is sunflower oil, wheat germ oil, grapeseed oil, corn oil, safflower oil, olive oil, evening primrose oil, borage oil, blackcurrent seed oil, chicken fat, butter oil or a marine animal oil.

10. A process as claimed in claim 1 or 2, wherein the water-soluble active principle is incorporated with vigorous stirring at a temperature above 60°C.

11. A process as claimed in claim 1 or 2, wherein the active principle is incorporated in the form of an aqueous solution or in dried form, after which water is added to the mixture in a quantity sufficient to hydrate the quantity of lecithin fraction which it contains.

12. A process as claimed in claim 11, wherein the water is 2 to 8% by weight of the mixtures and in that hydration takes place for 10 to 30 minutes in the absence of air.

13. A process as claimed in claim 11, wherein the heterogeneous mixture is dried by heating to 60-90°C under a vacuum of 0.5 to 35 mbar to obtain a homogeneous micellar phase.

14. A food, cosmetic or pharmaceutical product containing a homogeneous composition of a water-soluble active principle in a fat prepared by a process according to any one of claims 1 to 13.

15 15. A process for incorporating a water-soluble active principle in a fat which comprises treating phospholipids to produce a phospholipid fraction which is substantially free from phosphatidyl choline, forming a mixture of the phospholipid fraction and liquid fat, adding a water soluble active principle to a quantity of water with agitation for a sufficient period of time of about 10 to 30 minutes at a temperature of about 60°C. to about 80°C. and under an atmosphere sufficient to incorporate the water-soluble active principle into the water, adding a sufficient amount of the water to hydrate the phospholipid fraction to hydrate it and form a heterogeneous mixture, and drying the heterogeneous mixture to form a homogeneous composition.

16. A process as claimed in claim 15, wherein the treating step comprises mixing the phospholipids with the liquid fat to form an oil solution, treating the oil solution with an adsorbent to remove phosphatidyl choline from the phospholipids and separating the adsorbent from the oil solution.

17. A process as claimed in claim 15, wherein the treating step comprises mixing the phospholipids with one or more solvents to form a solvent solution, treating the solvent solution to liquid chromatography to separate the phospholipid fraction from the phosphatidyl choline and mast of the triglycerides.

18. A process as claimed in claim 15, 16 or 17, which further comprises selecting the water-soluble active principle to be a cosmetic agent, dermatological agent, antioxidant, or sequestering agent.

19. A process as claimed in any one of claims 15 to 18, which further comprises selecting the liquid fat to be rich in unsaturated fatty acids.

20. A process as claimed in any one of claims 15 to 19, which further comprises adding the water soluble active principle to the water in dried form.

21. A process as claimed in claim 20, wherein the amount of water is about 2 to 8% by weight of the mixture and hydration takes place for about 10 to 30 minutes in the absence of air which results in the formation of the heterogeneous mixture.

22. A process as claimed in claim 20, which further comprises removing the water from the heterogeneous mixture by heating the mixture to about 60-90°C. under a vacuum of about 0.5 to 35 mbar to obtain a homogeneous composition as a micellar phase.

23. A process as claimed in claim 2, which further comprises treating the oil solution with an adsorbent comprising a bleaching earth in an amount which is greater than the amount of phospholipids to thus remove substantially all of the phosphatidyl choline from the phospholipids and form the phospholipid fraction.

24. A process as claimed in claim 23 wherein the bleaching earth is added an amount of ate least about four times greater than the amount of phospholipids to remove substantially all of the phosphatidyl choline from the phospholipids and form the phospholipid fraction.

25. A process as claimed in claim 18, which further comprises selecting the water-soluble active principles to be vitamin C, vegetable extracts, organic acids, or amino acids.

26. A process as claimed in claim 19, which further comprises selecting the liquid fat to be sunflower oil, wheat germ oil, grapeseed oil, corn oil, safflower oil, olive oil, evening primrose oil, borage oil, blackcurrent seed oil, chicken fat, butter oil or a marine animal oil.

27. A process as claimed in claim 1, which further comprises providing the homogeneous composition with am oil stability index of at least about 11.5 hours at 110°C.

28. A process as claimed in claim 15, wherein the water-soluble active ingredient is vitamin C and the weight ratio of vitamin C to the phospholipid fraction is less than or equal to about 13% to ensure optimal stability of the composition.

29. The method of claim 15 wherein the water-soluble active principle is incorporated into the water under a nitrogen atmosphere at a temperature of about 80°C. for about 10 to 30 minutes.

30. A food, cosmetic or pharmaceutical product containing a homogeneous composition of a water-soluble active principle in a fat, prepared by a process according to any one of claims 15 to 29.