Carotenoids belongs the most widespread groups of naturally occurring pigments called as tetraterpenoids. These compounds are largely responsible for the red, yellow, and orange color of fruits and vegetables, and are also found in many dark green vegetables apart from higher plants these carotenoids are also present in certain type of algae, fungus and bacteria.
The most abundant carotenoids available through various food sources for human consumption are beta-carotene, alpha-carotene, gamma-carotene, lycopene, lutein, Zeaxanthin, beta-crpytoxanthin, and astaxanthin.
Beta-carotene, alpha-carotene, and beta-cryptoxanthin are significantly present in the orange-colored fruits and vegetables like mango, peach, apricot, and carrots. Green leafy vegetables like spinach, kale also contains beta-carotene, lutein and zeaxanthin. Lycopene is found in tomatoes, watermelons, pink guava, and grapefruit. Salmon, shellfish and egg yolks also reported to contains carotenoids. Micro-algae like Dunaliella Sp and Haematococcus sp are rich in beta-carotene and astaxanthin respectively, similarly there are wide range of micro organisms are capable of providing good commercial source for Natural carotenoids.
In recent days these natural carotenoids have gained significant important as a natural functional ingredient in Nutraceutical, food, cosmaceuticals and animal feed industries. Various studies shows that these carotenoids having a potential therapeutic property and as a potential use as natural coloring substances.
The increasing public health awareness and the strict health regulatory guidelines demands Natural, safe and healthier ingredients for various markets and applications hence there is a need for a environmentally safer, green technology and potential less health hazard compounds in the manufacturing of these natural products.
Our innovation answers these requirements in a way of providing highly concentrated natural carotenoids made without use of hazardous toxic organic solvents in the process.
Saponification or Hydrolysis is the state of art known and followed in the natural pigment or phyto-chemical industries for several years. Saponification is being carried out in order to break and liberates the fatty acid attached to the active molecules one of the typical example, the fatty acids diesters of lutein and zeaxanthin are naturally present in the oleoresin of marigold flower where hydrolysis is conducted to liberate the free form of carotenoids, another example is Lycopene extracted from tomato oleoresin, yet another example is capsanthin derived from the oleoresine of capsicul annum, similarly there are several example can be give for this process.
Thus the saponification or hydrolysis involves various methods including an aqueous strong alkali at different temperature in the presence of a surfactant or emulsifier or in an organic solvent strong alkali media or in an alcoholic alkali media or using hydrocarbons medium. In general the carotenoids are non soluble component in the hydrolysis media which gets crystallized and separated from the medium.
U.S. Pat. No. 7,875,751 discloses a method for the purification of carotenoids from plant extracts by saponification and purification, the saponification is done by using a polar solvent like methanol, ethanol and propan-2-ol and a non polar solvent like hexane, pentane and heptanes in the presence of an alkali, further the recovered crystals after drying are purified by re-crystallization under the presence of a water soluble solvent and deionized water. The process is highly complicated which involves different organic solvents & multiple steps for the purification
U.S. Pat. No. 7,812,198 discloses a Process for the manufacture of a composition containing xanthophylls by saponifying a marigold flower extract and isolating the xanthophylls in the presence of a quaternary ammonium base.
U.S. Pat. No. 7,629,007 describes a process for purification of free xanthophylls, according to this disclosure a xanthophylls-containing plant-derived oleoresin is saponified using alkali, then the saponified oleoresin is washed with a salt solution for several times before treating with organic solvents for further purification finally the free xanthophylls are filtered and dried.
U.S. Pat. No. 7,622,599 Provides an isolation and purification method for carotenoids from marigold flowers by hydrolyzing marigold oleoresin using alcoholic alkali followed by precipitation of the carotenoid crystals using hydro alcohol mixture, further the crystals are washed to remove impurities, finally the crystals are filtered & dried. This patent uses numerous solvents that generate mixed solvent streams that are costly on a commercial scale to recover and separate.
U.S. Pat. No. 7,485,738 describes a method for preparing high-content food-grade zeaxanthin through chemical isomarizaton reaction from Lutein by treating Xanthophylls crystals with glycol or propylene glycol with organic alkali to carry out isomarization, further the zeaxanthin crystals are precipitated under deionized water and alcohol mixture to collect Zeaxanthin crystals.
U.S. Pat. No. 7,253,294 discloses a process for the Isolation of Lutein from alfalfa by saponifying green plant oleoresin to provide a saponified resin, which is treated with first volatile organic solvent to oily substance which is further treated with a second volatile organic solvent to derive the Lutein.
U.S. Pat. No. 7,271,298 describes a Process for isolation and purification of xanthophylls crystals from plant oleoresin, where the process involves saponification of plant oleoresin containing xanthophyll diesters with alcohol & alkali and neutralizing the mixture by adding an acid and further washing the mixture with water and alcohol to remove impurities to get Xanthyphylls crystals.
U.S. Pat. No. 7,179,930 discloses a method of preparing a stable Lutein paste from oleoresin by several steps such as dissolving oleoresin in a solvent and purification by resin, then saponification of the esters using a catalyst, treating in an acidic solution, separating the solids, drying the esters and distillation of the alcoholic fraction. Accordingly, the described method is not a commercially viable method in view of the large number of steps involved.
U.S. Pat. No. 7,173,145 describes a process for extraction and purification of lutein, zeaxanthin and rare carotenoids the method employs tetrahydrofuran and alcohol, preferably ethanol, as the extraction solvents. In our process we do not use any organic solvent for saponification.
U.S. Pat. No. 7,138,152 teaches a method for extracting carotenoids from fruit and vegetable processing waste, the method involves by admixing the carotenoids source material with a first organic solvent and a surfactant to form a slurry then adding a second organic solvent which solubilizes the combination then separated into a liquid fraction and a solid fraction and further separation is carried out. The process doesn't discuss about the pure form of crystals and fail to discuss the recovery percentage for the carotenoids.
U.S. Pat. No. 6,797,303 describes a Carotenoid extraction process by making plant matter to greater than 10.degree then treating the material with organic solvent to extract the carotenoids, the major disadvantage of the process is not high purity yield & crystal recovery is not disclosed further we do not use any of the said organic solvents for extraction.
U.S. Pat. No. 6,743,953 describes saponification process and final purification step involving multiple solvents like ethyl acetate, hexane, acetone and methanol with the possibilities of leaving residues of the same in the final products.
U.S. Pat. No. 6,504,067 describe a process for cleaning oleoresin with alkali and acid then the oleoresin is subjected to aqueous alkali saponification for 8 hours in the presence of emulsifiers at a temperature of 90° C. The major disadvantage is longer saponification time thus prolonged exposure to heat might cause the degradation of the Lutein.
U.S. Pat. No. 6,380,442 describes a saponification process for carotenoids by using Isopropyl alcohol, water and alkali.
U.S. Pat. No. 6,329,557 discloses an industrial process for obtaining xanthophyll crystals from marigold oleoresin. Large amounts of organic solvent such as hexane and ketone are used in the process
U.S. Pat. No. 6,262,284 describes a method which uses THF (tetrahydrofuran) and alcoholic potassium or sodium hydroxide for isolating lutein and zeaxanthin by simultaneous extraction and saponification at room temperature.
U.S. Pat. No. 5,858,700 teaches a process for isolating and purifying lycopene crystals from a biological lycopene source by saponifying the source material using propylene glycol and aqueous alkali mixture to form lycopene crystals. The crystals are isolated and purified.
U.S. Pat. No. 5,847,238 describe a process for recovering xanthophylls from corn gluten by means of saponification and purifying the crude xanthophylls by methods of chromatographic separation. The method is difficult for industrial application, it will be quite expensive
U.S. Pat. No. 5,648,564 teaches a method for the saponification of marigold oleoresin is made in an aqueous solution in the presence of alcohol and propylene glycol at the temperatures of up to 70° C. and 10 hours to complete the saponification further the crystallization made using an organic solvent to recover the crystals. The process is quite long and there is possibility of oxidation of the carotenoids due to prolonged exposure to heat.
U.S. Application No. 2005/0139145 discloses a relatively simple method of purifying carotenoids which include lutein using organic solvents.
U.S. Application No. 2010/0280286 discloses a process for the conversion of lutein or lutein esters to Beta and Alpha Cryptoxanthin by using catalytic hydrogenation.
U.S. Application No. 2010/0305366 describes a lutein Extraction Processes by first extracting lutein esters by organic solvent and ultra-sound method then saponifying the lutein ester containing filtrate using alkaline solution further the solution is washed and separated to collect the crude crystals then finally it is recrystalised using tetrafuran and deionized water.
U.S. Application No. 2011/0065965 describes a saponification process of marigold oleoresin using an alkane hydrocarbon alkanol solution and potassium hydroxide then crystals are collected and further the collected crystals are washed with methanol-hexane solution and finally the crystals are separated.
Though there are number of methods; a simplified, less to no use of organic chemical solvents, economical and industrially feasible method to isolate Carotenoids is the need of the hour.