Process for the isolation of carotenoids

Abstract

Described herein is a material for reversibly binding to a carotenoid comprising a support coupled to silver ions in an amount to enable reversible binding with carotenoids, and wherein with the exception of silver ions, is substantially free of transition metals. Also described herein is a process for reversibly binding a carotenoid, the process comprising the steps of: providing a support coupled to silver ions in an amount to enable reversible binding with the carotenoid, wherein with the exception of silver, the support is substantially free of transition metals, contacting the support with the carotenoid under binding conditions to bind it thereto and dissociating the carotenoidod from the support under dissociating conditions to release the carotenoid.

Claims

1. A material for reversibly binding to a carotenoid, the material comprising: a support coupled to silver ions in an amount to enable reversible binding with said carotenoid, and wherein, with the exception of silver ions, said support is substantially free of transition metals.

2. The material of claim 1, wherein said support has a larger surface area relative to natural clay.

3. The material of claim 1, wherein said support has a total surface area of from 400 m.sup.2/g to 700 m.sup.2/g.

4. The material of claim 1, wherein the support has a substantially uniform chemical composition.

5. The material of claim 1, wherein said support is synthetic clay.

6. The material of claim 5, wherein said silver ions is monovalent, divalent or trivalent.

7. The material of claim 1, wherein said support is capable of at least partially or completely exchanging its indigenous cations with silver ions.

8. The material of claim 1, having a formula Na.sub.1.2-(X.Y)(Ag.sup.(Y))X[Mg.sub.4.8Li.sub.1.2Si.sub.8O.sub.20(OH).sub.4], wherein X is a number selected from 0.01-1.2; Y is a whole number selected from 1-3; and wherein the material has a net neutral charge.

9. The material of claim 8, wherein the multiple of X and Y is 1.2.

10. The material of claim 1, wherein substantially all of the carotenoid is capable of being dissociated from said support in an organic solvent.

11. The material of claim 1, wherein said support is a synthetic hectorite clay, wherein at least 70 mol % to 100 mol % of the sodium ions present in said hectorite clay have been exchanged with silver ions.

12. A process for reversibly binding the material according to claim 1 to a carotenoid, the process comprising the steps of: contacting the support with the carotenoid under binding conditions to bind it thereto; and dissociating the carotenoid from the support under dissociation conditions to release said carotenoid.

13. The process of claim 12, wherein the support is selected to have a higher surface area relative to natural clay.

14. The process of claim 13, wherein the support is selected to have surface area of from 400 m.sup.2/g to 700 m.sup.2/g.

15. The process of claim 12, wherein the support is selected to have a substantially uniform chemical material.

16. The process of claim 12, wherein the support is synthetic clay.

17. The process of claim 12, further comprising, prior to said contacting step, a step of at least partially or completely exchanging indigenous cations of said support with silver ions.

18. The process of claim 12, wherein said silver ions or silver of said silver-containing compound is monovalent, divalent or trivalent.

19. The process of claim 12, wherein the support has a formula: Na.sub.1.2-(X.Y) (Ag(.sup.Y)[Mg.sub.4.8Li.sub.1.2Si.sub.8O.sub.20(OH).sub.4], wherein X is a number selected from 0.01-1.2; and Y is a whole number selected from 1-3; and wherein the material has a net neutral charge.

20. The process of claim 19, wherein the support is selected such that the multiple of X and Y is 1.2.

21. The process of claim 12, further comprising the steps of: contacting the carotenoid with a wash solvent to form a washed carotenoid; and contacting the washed carotenoid with an organic solvent to form an extract phrase containing carotenoids.

22. The process of claim 12, wherein the support is incorporated into a filtration device.

23. The process of claim 12, wherein the carotenoid is provided in a liquid selected from a fruit oil, vegetable oil, or an extract derived from the group selected from carotenoid producing fungi, carotenoid producing bacteria, carotenoid producing microalgae, and carotenoid producing yeast.

24. The process of claim 23, wherein the liquid is a palm oil.

25. The process of claim 12, wherein the carotenoid is -carotene, -carotene, and combinations thereof.

26. The process of claim 23, wherein the support is present in an amount of about 0.01:1 to about 0.1:1 by weight relative to the liquid.

27. The process of claim 12, wherein the time for contacting the carotenoid with the support is from about 10 minutes to about 6 hours.

28. The process of claim 21, further comprising a step of removing the wash solvent prior to the step of contacting the washed carotenoid with said organic solvent.

29. The process of claim 28, wherein the organic solvent is selected from the group consisting of alkanes, alkenes, alkynes, alcohols, ketones, esters, ethers, and combinations thereof.

30. The process of claim 21, wherein the wash solvent and the organic solvent are food grade solvents.

31. The process of claim 21, further comprising a step of removing the organic solvent from the extract phase containing carotenoid by evaporation.

32. The process of claim 12, comprising the steps of: a. contacting palm oil with Ag.sub.2O, Ag.sup.+intercalated clay, or Ag-silicates thereby forming a mixture comprising a carotene complex and the palm oil; b. removing the palm oil; c. contacting the carotene complex with a food grade wash solvent thereby forming a washed carotene complex; d. removing the food grade wash solvent; e. extracting the carotene from the carotene complex with a food grade organic solvent to form an extract phase containing the carotene; and f. removing the food grade organic solvent from the carotene by evaporation.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The accompanying drawings illustrate disclosed embodiments and serves to explain the principles of the disclosed embodiments. It is to be understood, however, that the drawings are designed for purposes of illustration only, and not as a definition of the limits of the invention.

(2) FIG. 1 depicts X-ray diffraction analysis of a silver intercalated clay sample.

(3) FIG. 2 depicts X-ray diffraction analysis silver(I)oxide sample.

(4) FIG. 3 depicts X-ray diffraction analysis of a silver silicate sample.

(5) FIG. 4 depicts the UV-visible absorption spectrum of carotenoids separated from crude palm oil.

(6) FIG. 5 depicts the liquid chromatogram of (A) standard carotene (B) carotenoids separated from crude palm oil.

EXAMPLES

(7) Non-limiting examples of the present disclosure will be further described, which should not be construed as in any way limiting the scope of the disclosure.

Example 1

Preparation of a Synthetic Clay

(8) To synthesize the clay, MgCl.sub.2.6H.sub.2O (104 g), LiCl (1.3 g), Na.sub.2Si.sub.3O.sub.7 (166 g) and Na.sub.2CO.sub.3 (29.5 g) were dissolved in H.sub.2O (1800 ml). After stirring it for 30 minutes, the solution mixture was treated in a domestic microwave oven (2400 W, 60 minutes) The reaction product was filtered, washed with water (2500 ml) and was dried at 110 C. (16 hours) to yield 60 g of the desired synthetic clay.

(9) X-ray diffraction analysis of the synthetic clay indicates that it is a hectorite clay (Monoclinic, space group C 2/m) with a interlayer spacing of 16 ). X-ray fluorescence analysis of the prepared synthetic clay indicates the clay consists of Na.sub.2O (1.91%), MgO (17.76%), SiO.sub.2 (47.37%) by wt % and H.sub.2O.

Example 2

Preparation of a Silver Intercalated Synthetic Clay

(10) To the synthetic clay (5 g) prepared in example 1 dispersed in H.sub.2O (500 ml), a solution of AgNO.sub.3 salt (1 g) was added followed by stirring for 24 hours. Then the Ag-intercalated clay was filtered and washed with deionized H.sub.2O followed by drying at 80 C. (16 hours). The dried Ag-Clay was used for carotenoid separation.

(11) X-ray diffraction analysis of the synthetic clay indicates that the structure of the Ag intercalated synthetic clay is Ag.sub.1.2[Mg.sub.4.8Li.sub.1.2Si.sub.8O.sub.20(OH).sub.4] (FIG. 1). X-ray fluorescence analysis indicates that the silver intercalated clay consists of Ag (30-52 wt %) with MgO (5.02-12.28 wt %), SiO.sub.2 (16.64-30.37 wt %) and H.sub.2O (Table. 1).

(12) TABLE-US-00001 TABLE 1 X-ray fluorescence analysis of the silver intercalated clay Sample Compound w/w (%) Sample 1 MgO 5.02 SiO.sub.2 16.64 Ag 52.43 Loose Water 6.96 Bounded Water 8.24 OH + Volatile Organic 10.54 CO.sub.2 0.16 Total 100.00 Sample 2 MgO 12.28 SiO.sub.2 30.37 CaO 0.13 Cl 1.17 Ag 32.67 Loose Water 5.42 Bounded Water 7.94 OH + Volatile Organic 7.07 CO.sub.2 2.97 Total 100.00

Example 3

Preparation of Ago

(13) To a silver nitrate (2 g) solution (water, 50 ml) an aqueous solution of NaOH (0.7 g in 5 ml water) was added with constant stirring at room temperature for 15 minutes. The precipitate was dried at 80 C. for 2 hours and characterized by XRD and BET surface area (Yield 1.2 g).

(14) X-ray diffraction analysis indicated that the formed material was Ag.sub.2O with a small amount of Ago (FIG. 2).

Example 4

Preparation of Silver Silicate

(15) To a silver nitrate (1 g) solution (water, 30 ml) an aqueous solution of Na.sub.2Si.sub.3O.sub.7 (33 wt %) was added with constant stirring at room temperature for 10 minutes. Acetone (20 ml) was added to accelerate the precipitation of the desired product. The precipitate was washed with water (100 ml) followed by acetone (50 ml) and dried at 50 C. X-ray diffraction analysis shows that the formed material was Ag.sub.2SiO.sub.4 with some amorphous phases (FIG. 3).

Example 5

Isolation of Carotenoids From Palm Oil

(16) For carotene extraction, Ag-clay (0.5 g) was added to crude palm oil (10 g) with constant stirring. The optimum stirring was found to be 2 hours. The oil was separated from the carotenes absorbed clay by centrifugation followed by washing with an organic solvent (510 ml), the solvent could be preferably acetone, hexane. The washing was performed till the adsorbed oil came out and was identified by IR the glycerides CO peaks.

(17) Octadecene or 1,5-Hexadiene (5 ml) was then added to the washed carotenoid complex and allowed to mix. The hexadecane was then collected by filtering off the solids. The alkenes were then removed under reduced pressure to yield the isolated carotenoids. The separation was confirmed by UV-visible spectroscopy (FIG. 4) and liquid chromatography (FIG. 5). As shown in FIG. 4, it can be seen that the absorption was observed at 472 nm, 447 nm and 426 nm which are characteristic absorption peaks for carotenoids. In addition, it can be seen from the chromatograms in FIG. 5 that the retention time of the isolated carotenoids which contains carotene, separated from crude palm oil (B), is identical to that of standard carotene (A).

(18) Typical yield of carotenoids was 0.6-2.2 mg, which consisted of 35% of -carotene, 54% of -carotenes, 3% of -carotene and lycopene. This represents about a 10-70% recovery of the carotenoids initially present in the crude palm oil. The results of these experiments are tabulated in Table 2.

(19) TABLE-US-00002 TABLE 2 Carotenoids separated from crude palm oil Carotene ab- Wt % of sorbed (wt % absorbent of the initial Extraction Carotene Absorbent in CPO* concentration) solvent extracted Ag-Clay 2 8.2 Octadecene 0.1-0.5 mg/l Ag-Clay 2 8.2 1,5 0.8 mg/l Hexadiene Ag-Clay 5 11 1,5 1.2 mg/l Hexadiene Ag-Clay 10 14.2 1,5 6 mg/l(after Hexadiene + hexadiene soya oil is removed) AgO 2 16.8 1,5 1.87 mg/l Hexadiene AgO 2 16.8 1,5 4 mg/l(after Hexadiene + hexadiene soya oil is removed) Ag- 5 10 1,5 1.5 mg/l(after silicates Hexadiene + hexadiene soya oil is removed) *CPO = crude palm oil.

Example 6

The Effect of Temperature on the Isolation of Carotenoids from Palm Oil

(20) In another set of experiments, carotenoids were isolated from crude palm oil as described in Example 5, but the crude palm oil and clay mixture was heated at 40 C. The carotene separation amount was higher (0.6-4.2 mg) compared to the room temperature process.

Example 7

Isolation of Carotenoids from Palm Oil Using AgO

(21) In another set of experiments, Ag.sub.2O (0.2 g) was used instead of Ag-clay in the treatment of crude palm oil (10 g). The process was the same as described in Example 5 as discussed above. Using Ag.sub.2O, 0.6-1.8 mg of carotenoids were extracted from 10 g of crude palm oil.

Example 8

Isolation of Carotenoids from Palm Oil Using Ag-silicates

(22) In another set of experiments, Ag-silicates (0.2 g) was used instead of Ag-clay in the treatment of crude palm oil (6 g). The process was the same as described in Example 5 as discussed above. Using Ag-silicates, 0.5-1.5 mg of carotenoids was extracted from 10 g of crude palm oil.

Example 9

Effect of Crude Palm Oil Concentration on Carotene Recovery from Palm Oil

(23) In another set of experiments, the effect of concentration of the palm oil on carotenoid recovery was studied. Dilution of the crude palm oil with acetone and hexane (2 g of crude palm oil diluted in 15 ml of acetone or hexane) resulted in an increased carotenoid absorption when 0.5 g of Ag-clay was used. Hexane as solvent resulted in higher carotene binding compared to acetone solvent. This change resulted in an increase in carotenoids isolated in the concentrated extract phase from 45 ppm to 50 ppm.

(24) The complexed carotenoid from the carotenoid complex was separated by treating with other extraction solvents (hexadecene, 1,5 hexadiene, limonene, geraniol, sorbic acid, isoperene, -piene, myrcene, farnesene, farnesol, citral, caryophylene, zingiberene, 5 ml). The process involved stirring of the carotenoid complex in the presence of the solvent (15-30 minutes).

(25) The extraction solvents had high binding efficiency with the metal ions and hence replaced the carotene-metal ions bonding; carotene came out to the solvent medium. The extracted carotene was confirmed by IR and UV-spectroscopy.

(26) The above described process typically resulted in about 0.1 mg of isolated carotenoids, which represented a 20-80% recovery of the carotenoids initially present in the crude palm oil. The results of these experiments are tabulated in Table 3.

(27) TABLE-US-00003 TABLE 3 Carotenoids separated from crude palm oil % Carotene Wt % of absorbed (wt % absorbent % of of the initial Absorbent in CPO Dilution Heat concentration) Ag-clay 10 0 RT 16.7 Ag-clay 10 0 40 C. 60.5 Ag-clay 20 0 40 C. 77.6 Ag-clay 25 20 RT 21.48 (acetone) Ag-clay 25 20 RT 26.7 (hexane) Ag-clay 40 20 RT 70.2 (hexane) *CPO = crude palm oil; RT = room temperature.

APPLICATIONS

(28) The material, for reversibly binding to a carotenoid and the carotenoid isolation process described herein can be used in connection with the recovery and/or isolation of carotenoids, such as -carotene and -carotene, from a broad range of liquids containing such carotenoids. Exemplary liquids include palm oil, crude palm oil, crude palm olein, red palm oil/olein, palm stearin, neutralized red palm oil, neutralized red palm olein, sunflower oil, coconut oil, wheat germ, carrot oil, soybean, rapeseed, olive and derivative of such oils.

(29) The material and carotenoid isolation process can be used in the recovery and/or isolation of carotenoids from liquid extracts derived from, carotenoid producing fungi, carotenoid producing bacteria, carotenoid producing microalgae, and carotenoid producing yeast.

(30) The material and carotenoid isolation process can also be used in the recovery, isolation, and/or purification of carotenoids prepared by chemical synthesis. Crude carotenoids prepared by chemical synthesis can be diluted in an organic solvent. The resulting solution comprising the carotenoid can be subjected to the process described herein to at least partially purify the carotenoids present therein.

(31) The material and isolation process described herein can also be used in the recovery and/or isolation of other olefinic or poly/olefinic hydrocarbons from natural sources or in connection with the chemical synthesis of such compounds.

(32) The carotenoids provided by the material and, isolation process described herein have a wide range of benefits to human health due to their biological functions. Being an antioxidant, carotenoids are vital, for cell health due to their ability to prevent oxidative damage of the cellular components. Epidemiological evidence supporting a protective effect of carotenoids to the development of chronic and degenerative diseases, such as cancer, has grown considerably.

(33) Due to the nutraceutical properties of the carotenoids described herein, they are also commonly used in the food and biofuel industry. For example, they are used to reinforce fish color, which increases consumers' perception of quality. More importantly, carotenoids have been proposed as added-value compounds that could contribute to make, microalgal biofuel production economically feasible. High oil prices, competing demands between foods and other biofuel sources, and the world food crisis, have ignited interest in microalgae as promising feedstocks for biofuels. The productivity of these photosynthetic microorganisms in converting carbon dioxide into carbon-rich lipids greatly exceeds that of agricultural oleaginous crops, without competing for arable land. Hence, carotenoid-enriched microalgae production is steeply becoming an attractive business.

(34) It will be apparent that various other modifications and adaptations of the invention will be apparent to the person skilled in the art after reading the foregoing disclosure without departing from the spirit and scope of the invention. It is intended that all such modifications and adaptations come within the scope of the appended claims.