Lutein carotenoid extracts

Lutein is a major component of many plants. It is a component of most of the carotenoid extracts suggested as food colorants. 

The success of the carotenoid extracts led to the commercialization of synthetic carotenoids, some with the same chemical structure as those in the plant extracts and others with modifications to improve their technological properties. The yellow beta-carotene was synthesized in 1950, followed by the orange beta-8-carotenal in 1962 and the red canthaxanthin in 1964. A number of others soon followed, methyl and ethyl esters of carotenoic acid, citraxanthin, zeaxanthin, astaxanthin, and recently lutein. 

Fig. 2.24. C30 chromatograms of carotenoids extracted from human serum (a) xanthophylls fraction, 7 93 (v/v) MTBE-methanol mobile phase (b) a- and / -carotenes fraction, 11 89 (v/v) MTBE-methanol mobile phase (c) lycopene fraction, 38 62 (v/v) MTBE-methanol mobile phase. Tentative peak identifications (a) 1, 13-c/s-lu- lutein 2, 13 r/.vlutein 3, a//-/ra s-lutein 4, zeaan-thin 5-7, unidentified P,e-carotenoids and 8, / -cyrptoanthin (b) 1-2, unidentified ae-carotene isomers 3, 15-eH -/f-carotenc 4, 13-cw-/ -carotene 5, all-trans-a-carotene 6, all-trans-P-carotene and 7, 9-ci.v-/3-carotene and (c) 1-11 and 13, c/s-lycopene isomers and 12, all-trans-lycopene. Reprinted with permission from C. Emenhiser el al. [51].

Figure 4.6. Separation by HPLC of plant carotenoids extracted from untreated (A) and diflufenican-treated (B, C) carrot cells. Traces A and B were monitored at 450 nm trace C was monitored at 285 nm. 1, All- neoxanthin 2, violaxanthin 3, antheraxanthin 4, lutein 5, a-carotene 6, )3-carotene 7, phytofluenes 8, 15-Z phytoene. Data kindly provided by Dr. K. Pallett.

Most of this amount is in the form of fucoxanthin in various algae and in the three main carotenoids of green leaves lutein, violaxanthin, and neoxanthin. Others produced in much smaller amounts but found widely are p-carotene and zeaxanthin. The other pigments found in certain plants are lycopene and capsanthin (Figure 2.2.1). Colorant preparations have been made from all of these compounds and obviously the composition of a colorant extract reflects the profile of the starting material. Carotenoids are probably the best known of the food colorants derived from natural sources. ... 

Traditionally, dried or powdered plant material is used and extracts can be obtained by mixing the material with food-grade solvents like dichloromethane or acetone followed by washing, concentration, and solvent removal. The result is an oily product that may contain variable amounts of pheophytins and other chlorophyll degradation compounds usually accompanied by lipid-soluble substances like carotenoids (mainly lutein), carotenes, fats, waxes, and phospholipids, depending on the raw material and extraction techniques employed. This product is usually marketed as pheophytin after standardization with vegetable oils. 

Dunaliella natural P-carotene is distributed widely in many different markets under three categories p-carotene extracts, Dunaliella powder for human use, dried Dunaliella for feed use. Extracted purified P-carotene is sold mostly in vegetable oil in bulk concentrations from 1 to 20% to color various food products and for personal use in soft gels usually containing 5 mg P-carotene per gel. Purified natural p-carotene is generally accompanied by the other Dunaliella carotenoids, primarily lutein, neoxanthin, zeaxan-thin, violaxanthin, cryptoxanthin, and a-carotene for a total of approximately 15% of carotene concentration. This compound is marketed as carotenoids mix. ... 

In another study of carotenoid accumulation, cultured ARPE-19 cells were treated with a lipophilic extract from tomatoes solubilized in ethanol and injected into the culture medium for 24 h. The extract, containing 3-carotene, lycopene, and lutein at relative ratios of 23, 13, and 1, respectively, led to internalization of carotenoids at ratios of 9, 1.3, and 1, respectively (Chichili et al., 2006). These results indicate preferential accumulation of (3-carotene and lutein over lycopene in ARPE-19 cells. 

The HPLC analysis of milkweed, the food-plant source for Monarch butterflies, demonstrates that it contains a complex mixture of carotenoids including lutein, several other xanthophylls, xanthophyll epoxides, and (3-carotene, Figure 25.3b. There is a component in the leaf extract that is observed to elute near 8min, which has a typical carotenoid spectrum but is not identical to that of the lutein metabolite observed at near the same retention time in the extracts from larval tissue. 

Fig. 2.16. HPLC profile of carotenoids in an extract of vegetable soup. An expansion of the profile from 30 to 39 is shown in the inset (A). Monitored wavelengths were 436, 440, 464, and 409 nm for peaks 9,10,11,12, and 14, respectively, in the inset (A). Peak identification 1 + 1" = all-trans-lutein and cw-lutein 2 = 5,6-dihydroxy-5,6-dihydrolycopene (lycopene-5,6-diol) 3 = j3-apo-8 -carotenal (internal standard) 4 = lycopene 1,2-epoxide 5 = lycopene 5,6-epoxide 6 = 1,2-dimethoxyproly-copene (tentative identification) 7 = 5,6-dimethoxy-5,6-dihydrolycopene 8 = lycopene 9 = pheo-phytin b 10 = neurosporene 11 = (-carotene 12 = pheophytin a 13 = (-carotene 14 = pheophytin a isomer and (-carotene 15 = a-carotene 16 and 16" = all-trans-/fcarotene, cis-/J-carotene 17 and 17" = all-trans- or cA-phytofluene 18 and 18" = all-trans- or cw-phytoene. Reprinted with permisson from L. H. Tonucci et al. [40].

Extracts were further purified on neutral alumina cartridges conditioned by passing through 5 ml of hexane. Extracts were loaded in hexane and washed by 5 ml of hexane. The at- and /1-carotenes were removed by 3.5 ml of acetone-hexane (10 90, v/v), other carotenoids were eluted with acetone-hexane 30 70 and 70 30 v/v. Prepurification of pigments was performed in subdued light under a stream of nitrogen. Analyses were carried out in a C30 column (250 X 4.6 mm i.d., particle size 5/tm) using isocratic mobile phase composed of methyl-ferf-butyl ether (MTBE)-methanol (3 97 and 38 62, v/v) at a flow rate of 1 ml/min. The column was not thermostated separations were achieved at room temperature (about 23°C). Carotenoids were detected at 453 and 460 nm (lutein). The... 

Fig. 2.33. Chromatogram of the saponified extract of M. organophylum. Retention times (min) of analytes were astaxanthin (4.34), extracted carotenoid (4.65), Lutein (5.02), canthaxanthin (6.55) and /(-carotene (10.15). Reprinted with permission from P. Stepnowski et al. [75].

The complete separation from retinol to P-carotene requires -15 min. Figure F2.3.2 illustrates the separation of vitamins and carotenoids in the mixed food extract using this LC system. The elution order using this method is lutein, zeaxanthin, -cryptoxanthin, lycopene, a-carotene, and P-carotene. 

Figure F4.3.2 Absorption spectra of the major carotenoids of the photosynthetic biomembranes of green leaves of higher plants in diethyl ether (pure solvent). The carotenoids were freshly isolated from a pigment extract by TLC following Lichtenthaler and Pfister (1978) and Lichtenthaler (1987). P-C, p-carotene Lut, lutein Neo, neoxanthin Viola, violaxanthin.

Figure F4.3.4 Absorption spectra of pigments from a green tobacco leaf extracted with 100% acetone. The leaf extract was measured directly after extracting the leaf. Chi a, Chi b, and the carotenoids p-carotene (P-C) and lutein (Lut) were measured after separation by TLC.

Fig. 11 HPLC of carotenoids solvent-extracted from (A) raw and (B) thermally processed carrots. Column, 5-/um polymeric C1(J (250 X 4.6-mm ID) mobile phase, methyl tert-butyl ether/methanol (11 89), 1 ml/min absorbance detection, 453 nm. Tentative peak identifications (1) all-trans-lutein (2) 13-cis-a-carotene (3) a cis-a-carotene isomer (4) 13 -cA-a-carotene (5) 15-cis-/3-carotene (6) 13-cis-/3-carotene (7 and 8) cis-fi-carotene isomers (9) all-frans-a-carotene (10) 9-cis-a-carotene (11) all-frans-/3-carotene (12) 9-ci. -/3-carotene. (Reprinted with permission from Ref. 192. Copyright 1996, American Chemical Society.)...

While esterified xanthophylls can be extracted using solvent mixtures similar to those used for hydrocarbon carotenes, nonesterified xanthophylls are generally extracted using more polar solvents. For example, xanthophylls have been extracted from spinach using a mixture of methanol and tetrahydroftiran (Kopas-Lane and Warthesen, 1995). Acetone alone has also been used to extract lutein and zeaxanthin from a variety of fresh and processed vegetables (Updike and Schwartz, 2003). However, for the extraction of a wide range of carotenoids, a mixture of polar and nonpolar solvents works best. 

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