The present invention relates to a process for obtaining
stabilized lutein with about 95% yield from oleoresin at ambient temperature. The
lutein crystals are mixed with non water-soluble fractions to obtain a stable Lutein
paste. It is a method of separation, method of purification, and method of stabilization
without use of any additives.
Carotenoids are fat-soluble group of naturally occurring
plant pigments. Carotenoids can be divided into two main categories: Carotenes and
xanthophylls. Carotenes refer to carotenoids, which contain only carbon and hydrogen
atom, e.g. beta carotene, alpha carotene and lycopene. Xanthophylls refer to compounds
that contain an additional hydroxyl group or keto group or both. E.g. lutein, zeaxanthin.
Several studies have shown that consumption of fruit and
vegetable rich in carotenoids can offer protection against cancer, cardiovascular
and eye diseases. Since humans cannot make carotenes, they depend upon the diet
or supplementation as the source of these important nutrients. Carotenoids have
been found to possess potential membrane antioxidant activity due to their reactivity
with singlet oxygen and oxygen free radicals. Singlet oxygen has been implicated
in biological systems and is capable of damaging proteins, lipids and DNA. The anti-cancer
activity of carotenoids is attributable to the anti-oxygen activity of carotenoids.
Lutein is an important compound belonging to the group of carotenoids. Scientific
studies show that lutein plays a significant role in:
- 1. Prevention of age related macular degeneration of the eye.
- 2. Prevention of colon cancer.
Free radicals generated in the body during metabolism damage
the eye (more in the case of diabetes). Delicate tissues of the eye contain mainly
polyunsaturated fatty acids. They are very vulnerable to damage by free radicals
and oxidative stress. In healthy eye tissues large nutrients of antioxidants including
lutein exist to counter this damage. Various published studies suggest that intake
of lutein or caroteniods can lower eye diseases.
Lutein and zeaxanthin are highly concentrated in the macula
of eye. Macula is a small area of retina responsible for central vision and high
visual acuity. The yellow pigment of macula consisting of lutein and zeaxanthin
protect the macula from the damages of photoxidative effect of UV blue light. The
human body metabolises lutein to zeaxanthine. Lutein intake increases the serum
level of lutein and zeaxanthin and improves the function of UV blue blocking and
protection. Therefore lutein is emerging as an important nutrient for better health
and prevention of disease. There is increasing demand for lutein supplements from
the aging population of the world.
Carotenoids are present as plant pigments. They are very
readily obtained from flowers (marigold lagatea erecta), fruits (berries, tomatoes),
and roots (carrots, yellow potatoes). The hydroxyl caroteniods are found as esters
in the combined form.
They usually appear as diesters of lauric, myristic and
palmitic acid. In this form, they are very stable. However, the lutein esters (such
as dipalmitate of lutein from marigold) is not found in human serum.
STRUCTURE OF XANTHOPHYLL
Therefore, xanthophyll is an ester of lutein with chemical
combination with palmitic acid as indicated by "R" .With alkali hydrolysis the R
(palmitic acid) gets removed with the formation of free lutein (which is an alcohol)
as below.
LUTEIN
They partially undergo hydrolysis and only lutein is absorbed
into the serum. Therefore it is important to provide free lutein as supplement for
bioavailability. However, lutein in its free form is highly vulnerable to degradation
due to exposure to heat and oxidation. Lutein does not remain stable during storage.
Lutein gets converted into epoxide of lutein due to air oxidation. Therefore, the
real challenge here is how to stabilise lutein to improve shelf life and how to
minimize loss of lutein during the hydrolysis reaction. Stabilization without the
use of chemicals will be very important. There is an important need to create a
process for formation of free lutein, which is not exposed to temperature and long
processes and that can be made stable with natural stabilizing material without
using any chemical additives.
Lutein is currently available in the form of granules of
5%, 10% and in the form of stable pastes at 10%, 20% and 30% assay level. Free pure
Lutein at assay of 90% is not stable. It gets instantly oxidized to its epoxide.
This epoxide is not having any useful biological property. Lutein is normally stabilised
by adding chemical additives and is made available in assays ranging from 5% to
30%. This is stabilized with the addition of external stabilizing compounds such
as sorbic acid, sodium benzoate, polysorbate, polyethylen glycol, HPMC (hydroxypropyl
methyl cellulose), tocopherols, rosemarie extracts, vegetable oils. Even if pure
lutein is prepared it gets diluted by the addition or preservatives and stabilizing
agents to levels as mentioned above during stabilization. Many of these stabilizing
chemicals are very expensive too. Commercially available lutein is at very prohibitively
high prices due to its problems of stabilization, cumbersome process for preparation
and poor yields in manufacture due to its inherent instability.
In
U.S patent No 5,382,714 (Frederick Khaschik
), a method has been disclosed for isolation, purification and recrystallisation
of lutein from a saponified marigold oleoresin obtained under trademark KEMIN YELLOW
oil form KEMIN INDUSRIES, Inc, Des Moines Iowa. This patent has a major disadvantage
in that it does not specify an efficient method for release of lutein from the esters
as appearing in the plant. It provides a method of isolation of existing free lutein
in the input material. It perpetuates the inefficiency of transesterification as
done in the input raw material. This patent does not say anything about ester breaking
process. Besides, the process of purification suggested involves multiple solvents
and temperature of - 20° C. This does not lend itself as a commercially viable
process.
U.S Patent No 5,648,564 (Ausich et al
) discloses a process for saponification of lutein ester and purification
of free lutein. This process has 3 major disadvantages:
- 1. Saponification is carried out at high temperature of 65° C to 80°
C. This is high enough to cause degradation of lutein.
- 2. Saponification process time is typically at least 3 hours. Therefore the
reaction time is long. This combined with temperature leads to further degradation
of lutein.
- 3. The reaction is carried out in propylene glycol and ethanol and aqueous alkali.
The reaction mixture produced is a very viscous soapy material due to the presence
of water in the reaction mixture. It is very well known that lutein occurs as minute
crystals during the aqueous phase saponification reaction of marigold oleoresin.
This minute crystals get dispersed in the viscous mixture. The separation process
suggested in the patent does not efficiently recover all free lutein.
Therefore, this process is not a very efficient cost effective
commercial process.
U. S Patent No
5,876,782 (Sas et al
) describes a process for converting non-free form of xanthophyl to free
xanthophylls in the biomass. This process is suitable for low percentage of lutein
generation in biomass. Here again the process suffers from the disadvantage of high
temperature (69 degrees C) and long process time of 10 hours. Both these conditions
are harsh and cause degradation of lutein. This material is only suitable for animal
or poultry feed. As such is not suitable for human consumption.
U. S Patent No
6,262,284 B1 (Khachik
) describes a process for simultaneously extracting, saponifying and isolating
lutein and zeaxanthin in high purity from plant without the use of harmful organic
solvents. The saponification step is carried out at room temperature. This process
has very large volumes of solvent for extraction and saponification. The solvent
tetrahydrofuran is observed to degrades and produce peroxides. This peroxide can
degrade the carotenoid. The carotenoid in plant material is usually low at 1% to
2%. This low concentration of xanthophylls and the need to use high volume of solvent
make the process not very cost effective.
The meal to solvent ratio is 1:20 and total extractable
to solvent ratio is 1: 1000. This makes the commercial viability of the process
doubtful.
U.S Patent No 6,380,442 B1 (Madhavi et al
) describes a process for isolating and purifying mixed carotenoids containing
high concentration of specific compounds. The process employs the hydrolysis of
marigold oleoresin using isopropanol, water and alkali at 60 to 65° C for a
period of 90 minutes. While this process is certainly better than the previous process
in temperature and duration, it still suffers from the following disadvantages:
- 1. The hydrolysis temperature of 65° C is high and causes lutein degradation.
- 2. The reaction time of 90 minutes is still long and leads to oxidation at this
temperature.
- 3. The free lutein released during the aqueous phase hydrolysis is always very
minute crystals and they disperse in the slimy soapy solution. Presence of aqueous
alkali makes the reaction mixture very viscous. The process doe not offer a commercially
viable separation method for efficient recovery of free lutein. It is very difficult
to remove all precipitated crystals of lutein from the thick slimy soapy mixture
as per the suggested method.
U.S Patent No 6,504,067 B1 (Montoya et al
) describes a patent for cleaning of oleoresin with alkali and acid. This
cleaned oleoresin is subjected to aqueous alkali hydrolysis at a temperature of
90° C for a period of 8 hours in presence of certain emulsifiers for effective
contact. This process also suffers form disadvantage of high temperature and long
cycle time leading to degradation of free lutein along with separation issues as
described above.
WO02/060864
discloses a process for producing a stabilized lutein composition comprising:
a) shade drying marigold flower petals; b) extracting the dried marigold flow petals
of step a) with a solvent to produce an extract solution; c) passing the extracted
solution through a column packed with an anion exchange resin to obtain an eluent;
d) diluting the eluent to form a diluted solution; e) and recovering lutein crystals
from the diluted solution.
In view of the increasing demand for commercial lutein
as 10%, 20% or 30% product, there exists a need for no water, a room temperature,
low exposure time hydrolysis method for release of free lutein and its separation
from its esters that can be made stable during storage without the use of any chemical
additives. These minute crystals of lutein need to be separated effectively from
the fatty acid soap matrix to increase the overall yield. If the above - mentioned
features are addressed, one can develop a cost effective commercially viable process,
which will minimize lutein degradation due to temperature and oxidation and improve
yield by releasing free lutein from minimum soapy mass. This lutein can be stabilized
by a novel method without adding any additives. This lutein can be made available
as commercial lutein at 10%, 20% and 30% assay levels at viable prices.
The present invention relates to a process for obtaining
stabilized lutein.
Another object of the present invention is to develop a
process for obtaining high yield of pure lutein.
Yet another object of the present invention relates to
develop a process for obtaining lutein at ambient temperature, without spending
on heat energy.
Still another object of the present invention relates to
develop a process for obtaining lutein wherein the lutein obtained is a stable lutein
of about 35% assay.
Still another object of the present invention relates to
develop a process for obtaining lutein, which is stabile at ambient conditions for
at least few months 6 without any degradation.
Still another object of the present invention relates to
develop a process for obtaining lutein, wherein the lutein stays at normal storage
conditions and is amenable for commercial applications.
The present invention provides a novel method for hydrolysis
of xanthophyll into lutein without the use of water, at low temperature and with
minimum reaction time using phase transfer catalysts. The declared invention provides
a very efficient method for separation of fine crystalline lutein that get scattered
in the matrix of the soap that is produced during the hydrolysis. The proposed method
minimizes the formation of soap.
In accordance with certain embodiments of the present invention,
a very compact and cost effective method for the production of free and stable lutein
is provided, preferably in commercial products purity of 10%, 20% and 30% assay
level. This invention offers a process which minimize the degradation of temperature
labile lutein by accomplishing these processes in low temperature and in shorter
time cycles and also a method for stabilizing this lutein without any additives
and helps to make commercial grades of lutein.
Accordingly, the present invention relates to a process
for obtaining stabilized lutein with about 95% yield from oleoresin at ambient temperature,
said process comprising steps of dissolving cleaned oleoresin in alcohol to obtain
dissolved xanthophylls esters as clear solution on filtration, cleaning dissolved
oleoresin comprising xanthophylls esters in ion-exchange resin, hydrolyzing the
clear solution with base in presence of phase-transfer catalyst in alcohol medium,
quenching the hydrolyzed solution in water maintaining acidic pH to obtain undissolved
solids on filtration, dissolving the solids in ester to obtain ester layer on filtration,
drying ester layer to obtain semi-solid residue, triturating the semi-solid residue
in alcohol whereby obtaining lutein crystals of about 65% assay and an alcoholic
fraction, distilling the alcoholic fraction to obtain non water-soluble fractions,
and mixing the lutein crystals with non water-soluble fractions to obtain a stable
lutein paste.
In an embodiment of the present invention, wherein the
invention relates to process for obtaining stabilized lutein with about 95% yield
from oleoresin at ambient temperature, said process comprising steps of:
- a. dissolving cleaned oleoresin in alcohol to obtain dissolved xanthophylls
esters as clear solution on filtration,
- b. cleaning dissolved oleoresin comprising xanthophylls esters in ion-exchange
resin,
- c. hydrolyzing the clear solution with base in presence of phase-transfer catalyst
in alcohol medium,
- d. quenching the hydrolyzed solution in water maintaining acidic pH to obtain
undissolved solids on filtration,
- e. dissolving the solids in ester to obtain ester layer on filtration,
- f. drying ester layer to obtain semi-solid residue,
- g. triturating the semi-solid residue in alcohol whereby obtaining lutein crystals
of about 65% assay and an alcoholic fraction,
- h. distilling the alcoholic fraction to obtain non water-soluble fractions,
- i. mixing the lutein crystals of step (g) with non water-soluble fractions of
step (h) to obtain a stable lutein paste.
In another embodiment of the present invention, wherein
the alcohol is selected from a group comprising methanol, ethanol, propanol, butanol
and pentanol.
In yet another embodiment of the present invention, wherein
alcohol used in the process is butanol.
In still another embodiment of the present invention, wherein
the ion exchange resin used in the process is a strong base anion resin.
In still another embodiment of the present invention, wherein
the base is in powder form selected from a group comprising sodium hydroxide and
potassium hydroxide.
In still another embodiment of the present invention, wherein
the phase-transfer catalyst as used in the process is a quaternary salt.
In still another embodiment of the present invention, wherein
the quaternary salt of the process is selected from a group comprising quaternary
phosphonium salt and quaternary ammonium salt.
In still another embodiment of the present invention, wherein
the quaternary salts are tetra butyl ammonium bromide and tetra butyl ammonium hydrogen
sulphate.
In still another embodiment of the present invention, wherein
the ester is selected from a group comprising ethyl acetate, butyl acetate, amyl
acetate, and 2-ethyl hexyl acetate.
In still another embodiment of the present invention, wherein
the ester used in the process is ethyl acetate.
In still another embodiment of the present invention, wherein
quenching the reaction mass with urea.
In still another embodiment of the present invention, wherein
the pH is ranging between 3.2 to 4.3.
In still another embodiment of the present invention, wherein
the maintaining the pH with acetic acid.
In still another embodiment of the present invention, wherein
the filtering the solutions with filter paper.
In still another embodiment of the present invention, wherein
the oleoresin used in the process is marigold oleoresin.
In still another embodiment of the present invention, wherein
the triturating alcohol used in the process is ethyl alcohol.
In still another embodiment of the present invention, wherein
the stable lutein used in the process is of about 35% assay.
In still another embodiment of the present invention, wherein
the stabilized lutein stays at ambient conditions for a period of at least 6 months
without any degradation.
In still another embodiment of the present invention, wherein
the lutein stays at normal storage conditions, amenable for commercial applications.
In the present invention, we have utilized n-butanol as
the solvent, as it dissolves the xanthophyll ester fully and fulfills the above
criteria. The base selected are sodium hydroxide and potassium hydroxide solid powders
of 98% and 85% strength respectively. The phase transfer catalyst has been chosen,
from host of compounds comprising of quarternary phosphonium salts, quaternary ammonium
salts, preferably ammonium salts for their ability of ion pair capabilities. The
reaction conditions are developed to suit the hydrolysis mechanism of fatty esters.
In the present case care has been taken not to damage the formed lutein due to excess
heat, since the said compounds are thermolabile. The reaction temperature was between
40°C to 50°C preferably at 45°C. By maintaining the said condition
the reaction period was reduced to 30 mins. At 48°C the reaction needs only
1/2hrs for completion. At 40°C the period needed was 1 hrs atypical phase transfer
condition.
As a pretreatment to remove all free fatty acids of the
oleoresin to take care of the free acidity and subsequent viscous soap formation
during hydrolysis a treatment with ion exchange resin was introduced at temperatures
ranging between 40°C to 50°C.
The resin utilized was a strong base anion exchanger in
the form of either gel or macro porous resin. This process helps in minimal creation
of soapy matter and in better separation of lutein. This process improves lutein
yield.
The isolation was carried out by quenching the reaction
mass in demineralised water containing urea as a complexing agent. This is followed
by pH adjustment, filtration, extraction with an ester solvent in which lutein is
soluble. All the water -soluble reaction products such as soapy matter produced,
phase transfer catalyst etc., remain in as dissolved in the water phase. The ester
removes non - water - soluble products of reaction such as lutein, free fatty acid,
and wax from the original reaction mixture.
The said solvents are ethyl acetate, butyl acetate, amyl
acetate, 2-ethyl hexyls acetate, preferably ethyl acetate, at temperatures ranging
from 15°C to 50° C preferably at 40°C. The solvent is evaporated
at 45°C under vacuum.
The resulting paste from the previous process is mixed
with 4 to 5 volume of alcoholic solvent comprising of single carbon aliphatic to
penta carbon straight chain aliphatic alcohols. This is stirred well. Preferably
the alcohol used is ethanol, which is amicable for human consumption. The lutein
falls out as a solid. This is filtered and dried in vacuum oven to get lutein of
purity 55% to 60%. The alcoholic fraction is distilled under vacuum fully so as
to get a red pasty, material. This material consists of the non - water - soluble
fraction of the hydrolysis reaction and consist of free fatty acids and wax. This
is the residual material from the reaction mass after the release of lutein as crystals.
This is reddish orange in color as it still contains little unseparated lutein.
A surprising discovery has been made that if the purified lutein is mixed with this
fatty acid and wax combination, the lutein gets stabilized and remains in a stable
form without getting oxidized. The lutein, thus, obtained is blended in to this
pasty material by physical mixing in a laboratory ribbon blender. This resultant
paste has about 30% lutein and stays stable beyond 6 months at normal ambient conditions
of storage. The free lutein remains free. It does not chemically combine with fatty
acid or wax.
The invention is further elaborated with the help us following
examples and should not be construed to limit the scope of the invention.
EXPERIMENT 1
50 grams of marigold oleoresin containing 13.8 % by weight
lutein ester (xanthophylls-marigold oleoresin) is dissolved in 500 ml of n-butyl
alcohol at 40°C and filtered through filter paper to get a clear solution.
This solution is taken in a round bottom 3-neck flask attached with thermometer,
nitrogen sparge line and the inner temperature adjusted to 45°C. To the above
solution. 3.0 Gms of tetra butyl ammonium bromide is added and stirred for 5 minutes.
To the above solution 5 grams of sodium hydroxide powder was added and stirred.
The inner temperature raises 50°C due to reaction being exothermic. This is
cooled to 45°C. The reaction mass checked for the absence of starting material
after S hr. The reaction mass was quenched in 51trs of water containing 250
gms of urea. The pH of this solution was adjusted to 3.5 to 4.0 using 80 grams of
acetic acid. The reaction mass was filtered through filter paper. The retained solids
were dissolved in 250 ml of ethyl acetate at 35°C and filtered again to remove
insolubles. The ethyl acetate layer was dried with anhydrous sodium sulphate & distilled
out below 50°C to get a semisolid residue. The residue is triturated with 4
to 5 volumes of ethyl alcohol for 4hrs and filtered under nitrogen blanket. The
dry lutein crystals are collected and dried in a vacuum oven at 50°C. After
drying the vacuum is released using nitrogen and material is packed in black coloured
two layered food grade container. Final weight 6 grams and the assay of the lutein
is 52 % by UV method with an overall yield of 90% lutein.
EXPERIMENT 2
50 grams of marigold oleoresin containing 14.9 % by weight
lutein ester (oleoresin) is dissolved in 500 ml of n-butyl alcohol at 40°C
and filtered through filter paper to get a clear solution. This solution is taken
in a round bottom 3-neck flask attached with thermometer, nitrogen sparge line and
the inner temperature adjusted to 45°C. To the above solution. 3.0 Gms of tetra
butyl ammonium hydrogen Sulphate is added and stirred for 5 minutes. To the above
solution 5 grams of sodium hydroxide powder was added and stirred. The inner temperature
raises 50°C due to reaction being exothermic. This is cooled to 45°C.
The reaction mass checked for the absence of starting material after S hr.
The reaction mass was quenched in 51trs of water containing 250 gms of urea. The
pH of this solution was adjusted to 3.5 to 4.0 using 80 grams of acetic acid. The
reaction mass was filtered through filter paper. The retained solids were dissolved
in 250 ml of ethyl acetate at 35°C and filtered again to remove insolubles.
The ethyl acetate layer was dried with anhydrous sodium Sulphate & distilled out
below 60°C to get a semisolid residue. The residue is triturated with 4 to
5 volumes of ethyl alcohol for 4hrs and filtered under nitrogen blanket. The dry
lutein crystals are collected and dried in a vacuum oven at 50°C. After drying
the vacuum is released using nitrogen and material is packed in black coloured two
layered food grade container. Final weight 5.8 grams of assay of 58 % by UV method
at a yield of 91%.
EXPERIMENT 3
50 grams of marigold oleoresin containing 13.3% by weight
lutein ester (oleoresin) is dissolve in 200 ml of n-butyl alcohol and filtered to
get a clear solution. To the above solution 50ml of freshly regenerated strong base
anion exchange resin is added (e.g. Resin INDION 860). This solution is stirred
at 50 °C for 2hrs & cooled, resin filtered off. The resin was washed with 200
ml of butyl alcohol and washings combined with the filtrate. The total filtrate
3gms of tetra butyl ammonium bromide and 5gms of powdered sodium hydroxide was added
and stirred for 1 hrs at less than 50°C. The reaction is monitored using T.L.C.
and the work up was carried out as mentioned in the first experiment and final weight
is 6 grams having an assay of 52 % lutein with a yield of 94%.
EXPERIMENT 4
The above experiments were repeated using 5.3 grams of
potassium hydroxide powder in place of sodium hydroxide powder. The final work up
was as per the above two experiments. To get 5 grams and 5.5 grams of lutein respectively
of 60 % and 58 % assay by UV method.
EXPERIMENT 5
50 grams of marigold oleoresin containing 14.8 % by weight
lutein ester (oleoresin) is dissolved in 200 ml of n-butyl alcohol and filtered
to get a clear solution. To the above solution 50 ml of freshly regenerated strong
base an ion exchange resin is added. This solution is stirred at 50 °C for
2hrs & cooled, resin filtered off. The resin was washed with 200 ml of butyl alcohol
and washings combined with the filtrate. The total filtrate 3gms of tetra butyl
ammonium hydrogen Sulphate and 5 grams of powdered sodium hydroxide was added and
stirred for 1hrs at less than 50°C. The reaction is monitored using T.L.C.
and the work up was carried out as mentioned in the first experiment and final weight
is 6.1 grams of 54 % assay lutein.
EXPERIMENT 6
The above two experiments were repeated using 5.3 gms potassium
hydroxide solid in place of sodium hydroxide solid. And the reaction conditions
and work up were identical as mentioned in the earlier experiments. The weight of
lutein is 5.9 grams and 5.8 grams respectively of 58.3% and 58% assay.
EXPERIMENT 7
50 grams of marigold oleoresin containing 13.4 % by weight
lutein ester is dissolved in 200 ml of n-butyl alcohol and filtered to get clear
solution at 40°C. To the above solution under nitrogen atmosphere at 40 to
45° C added 3.0 grams of tetra butyl ammonium bromide and stirred for 5 minutes.
To the above solution 5 grams of powdered sodium hydroxide is added under stirring.
The inner temperature reached 45°C in 10 minutes due to exotherm, maintained
for S hr. After TLC checking and work up in urea & acetic acid as given in
experiment no. 1 to give a a paste. This paste was dissolved in 250 ml ethyl acetate
and the water removed by drying the solvent layer using anhydrous sodium sulphate.
The solvent layer is distilled under vacuum at 40° C to yield 19 grams of pasty
material. This paste was mixed with 100 ml of pure ethyl alcohol and stored at room
temperature till the paste dissolves in to ethyl alcohol. Afterwards, the stirring
was stopped and it was left to settle. This was filtered to get a lutein residue
after drying of 5.8 grams of 52%. The alcoholic fraction was distilled fully to
get a paste of 4.3 grams. This fraction is the non - water - soluble fraction of
the reaction products. This essentially consists of fatty acids and wax from the
reaction mixture. This material is used as a stabilising agent to stabilize free
lutein by mixing free lutein with this material. The lutein was mixed with this
paste in a laboratory blender to get a paste of 10.1 grams of Lutein paste. This
is free mixture of lutein with the paste. There is no chemical reaction here. This
material was analysed for free lutein content by spectrometer and found to be 30.2
% free lutein. This material was kept for storage stability at 35 to 40° C
in a double - layered black colored food grade container. In ambient conditions
of temperature and humidity (temp from 35 to 40 degrees C and relative humidity
of 49 to 76%) following are the results:
Duration
Initial
1st Month
2nd Month
3rd Month
4th Month
5th Month
6th Month
% Lutein
30.2
30.1
30.1
30.2
30.1
30.1
30.1
The above table shows no degradation of lutein under normal
ambient (35 to 40° C) storage conditions. Free lutein content is maintained
at 30.1% at the end of 6 months. This stable lutein paste compares with the maximum
assay available in commercial grade lutein. This can be used for the purposes of
usage in food and supplements. This also lends itself for conversion to 5% and 10%
billets and can be done by anybody skilful in the art.
The lutein is present originally in oleoresin as chemically
linked to neighbouring molecules. The hydrolysis of the present invention facilitates
isolation of the pure lutein. However, to stabilize the isolated, pure lutein, it
is mixed with non-water soluble fraction from the same source of lutein. The interaction
is a physical interaction and does not involve any chemical bondage. The lutein
is safely present in the matrix and can be used for various desired purposes.
Mixing of lutein with aforementioned fraction does stabilization.
There is no chemical reaction. Instead of the usual dangerous chemicals, we have
discovered that the part of this natural product can be used as a stabilizing agent.
In fact, the inventors themselves were surprised to notice such high stability of
lutein, without any significant loss in activity.
The instant invention provides for conditions of low temperature,
and short reaction time. This leads to less lutein damage during reaction. It further
enhances the yield.
Further, due to non-usage of water during the isolation
process, soap formation is reduced. This also minimizes loss of lutein.
The stabilized lutein can be safely used in foods and food-supplements.
The instant process obviates the need to stabilize lutein
with chemicals, which are expensive. Further, it helps distinguish our process from
conventional processes. Thus, the instant process is a much economical process.