Determination of β-Carotene in Commercial Foods: Interlaboratory Study

Two sample preparation procedures for determination of total β-carotene and (all-)-β-carotene were tested in a collaborative study involving 14 laboratories and using 4 commercial products containing supplemented or natural β-carotene. One assay used classical sample preparation, consisting of saponification, extraction, washing, and drying ofthe extract and redissolution of residue for liquid chromatography (LC). The other assay used simple extraction without saponification. LC conditions were left for the analysts to decide as long as aclear separation of lycopene and ϑ-carotene from Bcarotene was achieved. Mean contents of test samples ranged from 0.3 to 18 mg/100 g for total β-carotene and from 0.2 to 16 mg/100 g for (all-)-β-carotene. Repeatability relative standard deviations (RSDr)for total B-carotene ranged from 2.9 to 5.6% and relative reproducibility standard deviation (RSDR) ranged from 6.5 to 15%. Corresponding values for(all-)-β-carotene were 3.3-5.1 % for RSDr and 8.4- 14% for RSDR. Excluding the (Z)-isomers from uantitation of β-carotene can result in significant underestimation of the effective β-carotene content especially if the LC systems used is high quality.

Method for the Determination of Lycopene in Supplements and Raw Material by Reversed-Phase Liquid Chromatography: Single-Laboratory Validation

A single-laboratory validation study was conducted for a liquid chromatographic (LC) method for the determination of total and all-trans-lycopene in a variety of dietary supplements and raw materials. Gelatin-based and other water-dispersible beadlets, or tablets, capsules, and softgels containing such product forms, were digested with protease. Alginate formulations and the respective applications were treated with an alkaline sodium EDTA acetate buffer to release lycopene from the matrix. Lycopene and other carotenoids were extracted from the resulting aqueous suspensions with dichloromethane and ethanol. Oily product forms were directly dissolved in dichloromethane and ethanol. The extracts were chromatographed on an isocratic high-performance LC system using a C16 alkylamide modified silica column that provided satisfactory resolution of all-trans-lycopene from its predominant cis-isomers and separated the lycopene isomers from other carotenoids such as - and -carotene, cryptoxanthin, lutein, and zeaxanthin. The within-day precision relative standard deviation (RSD) for the determination of total lycopene ranged from 0.9 to 5.7 over concentration ranges of 50200 g/kg for raw materials and 0.324 g/kg for dietary supplements. The intermediate precision RSD (total RSD) ranged from 0.8 to 8.9. Recoveries obtained for beadlet and tablet material for the different extraction variants ranged from 95.0 to 102.1 at levels of 0.0220 g/kg for tablets and from 95.0 to 101.1 at levels of 1200 g/kg for beadlet material.

Determination of β-Carotene in Supplements and Raw Materials by Reversed-Phase High Pressure Liquid Chromatography: Collaborative Study

Twelve laboratories representing 4 countries participated in an interlaboratory study conducted to determine all-trans-β-carotene and total β-carotene in dietary supplements and raw materials. Thirteen samples were sent as blind duplicates to the collaborators. Results obtained from 11 laboratories are reported. For products composed as softgels and tablets that were analyzed for total β-carotene, the reproducibility relative standard deviation (RSDR) ranged from 3.35 to 23.09% and the HorRat values ranged from 1.06 to 3.72. For these products analyzed for trans β-carotene, the reproducibility relative standard deviation (RSDR) ranged from 4.28 to 22.76% and the HorRat values ranged from 0.92 to 3.37. The RSDr and HorRat values in the analysis of a beadlet raw material were substantial and it is believed that the variability within the material itself introduced significant variation in subsampling. The method uses high pressure liquid chromatography (LC) in the reversed-phase mode with visible light absorbance for detection and quantitation. If high levels of α-carotenes are present, a second LC system is used for additional separation and quantitation of the carotene species. It is recommended that the method be adopted as an AOAC Official Method.

Method for the Determination of β-Carotene in Supplements and Raw Materials by Reversed-Phase Liquid Chromatography: Single Laboratory Validation

A single laboratory validation (SLV) study was conducted for a liquid chromatography (LC) method for the determination of total and all-trans-β-carotene in a variety of dietary supplements, including multivitamin tablets, softgels, capsules, and beadlet raw materials. Extraction variants were developed for the different types of supplements tested based upon the supplement type and level of β-carotene. Water dispersible formulations such as powders, emulsions, tablets, and capsules were enzymatically digested with protease and extracted with dichloromethane–ethanol. Oily suspensions were directly dissolved in dichloromethane–ethanol. After appropriate dilution or concentration, the extracts were chromatographed by using either a reversed-phase C18 column or, in products containing high amounts of α-carotene, a reversed-phase C30 column. The LC systems provided linear responses in the range of 0.1–50 μg β-carotene/mL. The main geometrical isomers of β-carotene (all-trans, 9-cis, 13-cis, and 15-cis) were well separated from each other and from other carotenoids such as α-carotene, cryptoxanthin, lutein, lycopene, and zeaxanthin. Duplicate determinations of total β-carotene performed by 2 technicians in 8 different test materials on 5 different days resulted in relative standard deviations of 1.2–4.4%. Recoveries determined for supplements and beadlet raw material spiked with β-carotene levels of 10 μg to 100 mg/test portion and 0.2–40%, respectively, ranged from 97.5 to 102.1%. On the basis of the accuracy, precision, and recovery results from the SLV study, the method is suggested for a collaborative study on the determination of total and all-trans-β-carotene in dietary supplements.

Pigment-depletion in Atlantic salmon (Salmo salar) post-smolt starved at elevated temperature is not influenced by dietary carotenoid type and increasing α-tocopherol level

Pigment-depletion in the fillets of farmed Atlantic salmon (Salmo salar) arises after periods of elevated water temperatures with voluntary starving. This study tested the effects of dietary pre-loading with different pigment carotenoids (astaxanthin and/or canthaxanthin) combined with two α-tocopherol levels (normal and high: 500 and 1000 mg/kg, respectively) on pigment-depletion in vivo in Atlantic salmon after four weeks of challenge. We also tested whether oxidative stress manifested as an underlying depletion mechanism. Carotenoid levels in whole fillet homogenates were not decreased significantly post-challenge but fillet α-tocopherol concentrations were increased significantly in contrast to decreased oxidative stress indices. However, image analysis revealed localised fillet pigment-depletion following all dietary treatments. These data imply that localised pigment-depletion was not prevented by pre-loading of the fillet with different carotenoid-types/mixtures and increased of α-tocopherol levels from normal to high, respectively. Further, we suggest that oxidative stress might not facilitate pigment-depletion in vivo.

Determination of Lycopene in Dietary Supplements and Raw Materials by High-Performance Liquid Chromatography: Collaborative Study

A collaborative study was conducted to evaluate the interlaboratory performance of an LC method for lycopene in dietary supplements and the raw materials commonly used in their manufacture. Twelve laboratories from six countries agreed to participate in the study. Results from 10 laboratories were received and are reported. Five dietary supplements, including both tablets and a softgel capsule with a lycopene content ranging from 25 g to 25 mg per unit, and three raw materials, including gelatin-based beadlets, vegetarian beadlets, and a suspension in oil ranging from 5 to 20 lycopene, were analyzed as blind duplicates. In addition to the commercial products, two positive controls and a negative control were included in the study. For the raw materials studied, the repeatability relative standard deviations (RSDr) ranged from 1.49 to 5.13 for total lycopene, and the reproducibility relative standard deviations (RSDR) ranged from 3.84 to 9.21 with HorRat values from 1.23 to 3.24. For finished products, the RSDr ranged from 1.31 to 4.62, RSDR from 4.28 to 10.5, and HorRat values from 0.79 to 2.07. Corresponding values for all-trans-lycopene were significantly higher. It is recommended that the method be considered for Official First Action for all-trans- and total lycopene in finished products and raw materials.

Determination of lycopene in dietary supplements and raw materials by high-performance liquid chromatography: collaborative study

A collaborative study was conducted to evaluate the interlaboratory performance of an LC method for lycopene in dietary supplements and the raw materials commonly used in their manufacture. Twelve laboratories from six countries agreed to participate in the study. Results from 10 laboratories were received and are reported. Five dietary supplements, including both tablets and a softgel capsule with a lycopene content ranging from 25 microg to 25 mg per unit, and three raw materials, including gelatin-based beadlets, vegetarian beadlets, and a suspension in oil ranging from 5 to 20% lycopene, were analyzed as blind duplicates. In addition to the commercial products, two positive controls and a negative control were included in the study. For the raw materials studied, the repeatability relative standard deviations (RSDr) ranged from 1.49 to 5.13% for total lycopene, and the reproducibility relative standard deviations (RSDR) ranged from 3.84 to 9.21% with HorRat values from 1.23 to 3.24. For finished products, the RSDr ranged from 1.31 to 4.62%, RSDR from 4.28 to 10.5%, and HorRat values from 0.79 to 2.07. Corresponding values for all-trans-lycopene were significantly higher. It is recommended that the method be considered for Official First Action for all-trans- and total lycopene in finished products and raw materials.

Carotenoid and vitamin content ofKaratand other Micronesian banana cultivars

We previously found high carotenoid levels in Karat and other Micronesian bananas, indicating potential importance for alleviating vitamin A deficiency and other nutritionally related health problems in the Federated States of Micronesia. Past work focused on carotenoid and mineral analyses, whereas here we investigated 16 cultivars (most not previously analysed) for a broader micronutrient profile, including seven vitamins. Karat carotenoid levels were higher than in previous analyses, confirming Karat as exceptionally carotenoid-rich. We identified an additional 10 carotenoid-rich cultivars, expanding the range having potential for alleviating vitamin A deficiency. A striking finding is the high riboflavin level in Karat, including high levels of uncharacterized flavonoids. Niacin and alpha-tocopherol are at levels that may contribute importantly to dietary intake within normal patterns of consumption. These data present a more complete basis for promoting the nutritional benefits of these banana cultivars where they are consumed in the Pacific, and potential benefits for promoting elsewhere.

Metabolism of lutein and zeaxanthin in rhesus monkeys: identification of (3R,6'R)- and (3R,6'S)-3'-dehydro-lutein as common metabolites and comparison to humans

Lutein and zeaxanthin are xanthophylls that can be found highly concentrated in the macula of the retina. They are thought to protect the macula through their role as blue-light filters and because of their antioxidant and singlet oxygen quenching properties. Examination of metabolites unique to lutein and zeaxanthin such as 3'-dehydro-lutein, and of their stereochemistry may provide insight to the mechanism by which they are formed and by which they exert protection. To evaluate the formation of such metabolites, eleven monkeys were raised on a xanthophyll-free diet, and supplemented with pure lutein or pure zeaxanthin (2.2 mg/kg body weight/d). The period of supplementation ranged between 12 and 92 weeks. At study start and throughout the study, serum samples were taken and analyzed for xanthophylls using different HPLC systems. Xanthophyll metabolites were identified using UV/VIS and HR-MS detection. Lutein and zeaxanthin metabolites were found in detectable amounts with 3'-dehydro-lutein being a common metabolite of both. Using chiral-phase HPLC, two diastereomers, (3R,6'R)-3'-dehydro-lutein and (3R,6'S)-3'-dehydro-lutein, were identified and shown to be present in nearly equimolar amounts. A pathway for their formation from either lutein or zeaxanthin is proposed. These findings were comparable to results obtained with human plasma.

Carotenoid content of pandanus fruit cultivars and other foods of the Republic of Kiribati

Background

Kiribati, a remote atoll island country of the Pacific, has serious problems of vitamin A deficiency (VAD). Thus, it is important to identify locally grown acceptable foods that might be promoted to alleviate this problem. Pandanus fruit (Pandanus tectorius) is a well-liked indigenous Kiribati food with many cultivars that have orange/yellow flesh, indicative of carotenoid content. Few have been previously analysed.

Aim

This study was conducted to identify cultivars of pandanus and other foods that could be promoted to alleviate VAD in Kiribati.

Method

Ethnography was used to select foods and assess acceptability factors. Pandanus and other foods were analysed for β- and α-carotene, β-cryptoxanthin, lutein, zeaxanthin, lycopene and total carotenoids using high-performance liquid chromatography.

Results

Of the nine pandanus cultivars investigated there was a great range of provitamin A carotenoid levels (from 62 to 19 086 μg β-carotene/100 g), generally with higher levels in those more deeply coloured. Seven pandanus cultivars, one giant swamp taro (Cyrtosperma chamissonis) cultivar and native fig (Ficus tinctoria) had significant provitamin A carotenoid content, meeting all or half of estimated daily vitamin A requirements within normal consumption patterns. Analyses in different laboratories confirmed high carotenoid levels in pandanus but showed that there are still questions as to how high the levels might be, owing to variation arising from different handling/preparation/analytical techniques.

Conclusions

These carotenoid-rich acceptable foods should be promoted for alleviating VAD in Kiribati and possibly other Pacific contexts where these foods are important. Further research in the Pacific is needed to identify additional indigenous foods with potential health benefits.

Method for the determination of beta-carotene in supplements and raw materials by reversed-phase liquid chromatography: single laboratory validation

A single laboratory validation (SLV) study was conducted for a liquid chromatography (LC) method for the determination of total and all-trans-beta-carotene in a variety of dietary supplements, including multivitamin tablets, softgels, capsules, and beadlet raw materials. Extraction variants were developed for the different types of supplements tested based upon the supplement type and level of beta-carotene. Water dispersible formulations such as powders, emulsions, tablets, and capsules were enzymatically digested with protease and extracted with dichloromethane-ethanol. Oily suspensions were directly dissolved in dichloromethane-ethanol. After appropriate dilution or concentration, the extracts were chromatographed by using either a reversed-phase C18 column or, in products containing high amounts of alpha-carotene, a reversed-phase C30 column. The LC systems provided linear responses in the range of 0.1-50 microg beta-carotene/mL. The main geometrical isomers of beta-carotene (all-trans, 9-cis, 13-cis, and 15-cis) were well separated from each other and from other carotenoids such as a-carotene, cryptoxanthin, lutein, lycopene, and zeaxanthin. Duplicate determinations of total beta-carotene performed by 2 technicians in 8 different test materials on 5 different days resulted in relative standard deviations of 1.2-4.4%. Recoveries determined for supplements and beadlet raw material spiked with beta-carotene levels of 10 microg to 100 mg/test portion and 0.2-40%, respectively, ranged from 97.5 to 102.1%. On the basis of the accuracy, precision, and recovery results from the SLV study, the method is suggested for a collaborative study on the determination of total and all-trans-beta-carotene in dietary supplements.

Influence of source and ratio of xanthophyll pigments on broiler chicken pigmentation and performance

One experiment was conducted using 960 1-d-old, sexed broilers of Ross 308 strain from 1 to 43 d to evaluate if one type of chemically isomerized marigold with 25% of xanthophylls as zeaxanthin (SME-25) could produce pigmentation equivalent to the current addition of conventional marigold with 10% of xanthophylls as zeaxanthin (SME-10) plus canthaxanthin (CTX) in practical broiler diets (maize-wheat-soybean). Birds were allocated in 32 pens, in a randomized complete block design (four blocks x four treatments). The treatments consisted of a nonpigmented control (T1), a combination of 35 ppm of yellow xanthophylls (YX) from SME-10 + 5 ppm of CTX (T2), a combination of 32 ppm of YX from SME-10 + 2 ppm of CTX (T4), and one treatment with 40 ppm of YX from a new SME-25 (T3). There were no significant treatment effects on chicken performance. All color parameters (Minolta coordinates, Roche color fan scores, Rank test) presented significant differences (P < 0.0001) because of dietary pigments on shanks and breast skin. Birds fed the SME-25 diet had less pigmentation than those fed equivalent quantities of a combination of SME-10 + CTX. The Minolta coordinate "b" measured in breast skin was a good indicator of YX content in feed, whereas the "a" coordinate measured on the shank showed a linear relationship with the dietary CTX level (r = 0.61, P < 0.0001). The same visual color classification of chickens was achieved irrespective of the rank test performed (by shank or carcass color). Lutein and zeaxanthin from the SME-25 product had lower deposition rates in skin and fat tissues than those from the SME-10 product. This finding seems to be related to the ratio of zeaxanthin stereoisomer RR (optically active) vs. RS that was found in tissues from the SME-10 product (97.8%:2.2%), whereas with SME-25 this ratio was 16.0:84.0%. These results suggest that inclusion of only the SME-25 product could not replace the current addition of SME-10 and CTX combinations.

Isolation and characterization of the carotenoid biosynthesis genes of Flavobacterium sp. strain R1534

The Gram-negative bacterium Flavobacterium sp. strain R1534 is a natural producer of zeaxanthin. A 14 kb genomic DNA fragment of this organism has been cloned and a 5.1 kb piece containing the carotenoid biosynthesis genes sequenced. The carotenoid biosynthesis cluster consists of five genes arranged in at least two operons. The five genes are necessary and sufficient for the synthesis of zeaxanthin. The encoded proteins have significant homology to the crtE, crtB, crtY, crtI and crtZ gene products of other carotenogenic organisms. Biochemical assignment of the individual gene products was done by HPLC analysis of the carotenoid accumulation in Escherichia coli host strains transformed with plasmids carrying deletions of the Flavobacterium sp. strain R1534 carotenoid biosynthesis cluster.