Lutein Esters Research Articles

Effect of supplementation with lutein, zeaxanthin, and omega-3 fatty acids on macular pigment and visual function in young adults with long-term use of digital devices: study protocol for a randomized double-blind placebo-controlled study

BackgroundGrowing evidence emphasizes the importance of xanthophyll carotenoids and omega-3 fatty acids in eye health. However, the beneficial effects of such supplementation have not been thoroughly discussed among adults with high screen exposure. Current trial evidence on lutein bioavailability is contradictory, and the interactions of dietary intervention with host-related factors remain elusive. This study aims to investigate the comparative effectiveness of supplementation with macular xanthophylls and omega-3 fatty acids on macular pigment optical density (MPOD) and visual function, access the bioavailability of free lutein and lutein ester, and explore the complex interplay between genetic variations, intestinal microbiota, and the dietary intervention in Chinese adults with long-term exposure to digital devices.MethodsThe Lutein, Zeaxanthin, and Omega-3 (LZO) clinical trial is a 24-week multicenter, randomized, double-blind, placebo-controlled trial of 600 participants recruited from research centers, universities, and communities. Individuals are eligible to participate if they are aged over 18 years and use digital devices for over 8 h daily in the last 2 years, and will be randomized to six arms. A total of three visits will be scheduled at baseline, 12 and 24 weeks. The primary outcome is the change in MPOD over the 24-week intervention. The secondary outcomes are changes in visual function (visual acuity, best-corrected visual acuity, contrast and glare sensitivity, critical flicker fusion, reaction time, visuognosis persistence, symptoms and signs of dry eye, retinal thickness, and optical quality), and changes in serum lutein and zeaxanthin concentrations, and erythrocyte membrane omega-3 fatty acids. Genetic variations will be determined using genome-wide genotyping at baseline. 16S rRNA gene sequencing will be utilized to assess microbiome compositional changes before and after intervention.DiscussionThe trial is anticipated to establish early interventions to prevent photochemical ocular damage and delay the onset of vision impairment in young adults with long-term repeated exposure to screen-based electronic devices, and provide valuable insights for the development of precision nutrition strategies for maintaining eye health.Clinical trial registrationwww.clinicaltrials.in.th, Identifier, TCTR20220904002.

Metabolomic and Transcriptomic Analysis of Unique Floral Coloration in Osmanthus fragrans Cultivars

The floral color phenotypes of Osmanthus fragrans cultivars range from light yellow to orange yellow, with ‘Yanzhi Hong’ being the only reported cultivar with a red color. However, the underlying reason for this unique floral coloration remains unclear. The study conducted targeted metabolomics and transcriptomics analyses on the petals of ‘Yanzhi Hong’ at both initial and peak flowering stages. Candidate gene expression was validated, and expression levels of the petals of three cultivars were compared using RT-qPCR. The results revealed the presence of 27 components in the petals of ‘Yanzhi Hong’, including 5 carotenoids, 8 xanthophylls, and 14 xanthophyll esters. Notably, lycopene was detected in abundance for the first time in O. fragrans cultivars. Carotenes accounted for 78.82 ± 3.17% and 91.19 ± 1.69% of the total carotenoid content in petals during the initial and peak flowering stages, respectively, with all carotene contents increasing during the peak flowering period. β-carotene, lycopene, and γ-carotene were identified as the top three carotene components in petals during both initial and full flowering stages. The unique blush red color of ‘Yanzhi Hong’ petals could be attributed to the low content of α-carotene and the rich accumulation of lycopene. Furthermore, a total of 1550 differentially expressed genes (DEGs) were identified in petals at the peak flowering stage relative to the initial flowering stage, with 1003 genes being downregulated and 547 genes being upregulated during the full flowering stage. There are 926 differentially expressed genes (DEGs) annotated in the Gene Ontology (GO) database. Among these DEGs, those that were downregulated and upregulated during the peak flowering period showed significant enrichment in carbohydrate metabolism and oxidation–reduction processes, respectively. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis identified 14 structural genes associated with phenylpropanoid biosynthesis and 7 structural genes linked to carotenoid biosynthesis. Expression levels of candidate genes involved in carotenoid biosynthesis were examined in the petals of three cultivars (‘Yanzhi Hong’, ‘Liuye Jingui’, and ‘Gecheng Dangui’) at both the initial and peak flowering stages. The results indicated that the decreased expression of LYG009054 (LYCE) and LYG018651 (LYCB) in ‘Yanzhi Hong’ resulted in higher lycopene accumulation and lower α-carotene content in the petals. This study offers valuable insights into the mechanisms underlying the unique flower color phenotype of O. fragrans, proving a basis for further research on carotenoid metabolism pathways and the breeding of new cultivars with a variety of flower colors in O. fragrans.

Physicochemical properties, photostability, and digestive characteristics of natural emulsion system fabricated by recombinant rice bran oil bodies for lutein ester delivery

Rice bran oil bodies (RBOBs), as natural oil-in-water emulsions, can be used as a good carrier for delivering hydrophobic functional ingredients. In this work, the lutein ester-loaded rice bran oil body (LRBOB) emulsions were successfully prepared by restructuring the RBOBs natural structure through heat treatment and high-pressure homogenization. The physicochemical properties, photostability, and in vitro digestion of LRBOB emulsions with different oil body concentrations were investigated. The LRBOB emulsion with 50% RBOBs had maximum lutein ester encapsulation efficiency (94%) with larger mean particle size (566.44 ± 18.05 nm) and zeta potential (−43.87 ± 0.8 mV), exhibiting good physical stability and an amorphous structure of lutein ester. Meanwhile, the emulsion droplets formed a network structure through mutual adsorption, as observed by CLSM. Moreover, the apparent viscosity of LRBOB emulsion was increased with the increase of RBOBs concentration, showing a shear thinning behavior. Within the linear viscoelastic range, the emulsions mainly displayed elastic rheological characteristics. Furthermore, the photooxidation studies showed that the LRBOB emulsion retained a maximum of 37% lutein ester after 96 h of UV irradiation, and the half-life was extended to 58.89 h. Meanwhile, a higher amount of RBOBs effectively reduced lipid and protein oxidation and minimized color difference, indicating that RBOBs could effectively improve the stability of lutein ester. Based on the results of in vitro simulated digestion, LRBOB emulsion showed higher free fatty acid release (32%) and lutein ester bioaccessibility (40.17%) in the adult model, but is not recommended for infant diets. This work will provide a new delivery vehicle for the utilization of raw lutein materials, expanding the potential applications of natural plant oil bodies.

Bioavailability of Lutein from Marigold Flowers (Free vs. Ester Forms): A Randomised Cross-Over Study to Assess Serum Response and Visual Contrast Threshold in Adults.

Lutein (Lut) and zeaxanthin (Zeax) are found in the blood and are deposited in the retina (macular pigment). Both are found in the diet in free form and esterified with fatty acids. A high intake and/or status is associated with a lower risk of chronic diseases, especially eye diseases. There is a large global demand for Lut in the dietary supplement market, with marigold flowers being the main source, mainly as lutein esters. As the bioavailability of Lut from free or ester forms is controversial, our aim was to assess the bioavailability of Lut (free vs. ester) and visual contrast threshold (CT). Twenty-four healthy subjects (twelve women, twelve men), aged 20-35 and 50-65 years, were enrolled in a cross-sectional study to consume 6 mg lutein/day from marigold extract (free vs. ester) for two months. Blood samples were taken at baseline and after 15, 40, and 60 days in each period. Serum Lut and Zeax were analysed using HPLC, and dietary intake was determined with a 7-day food record at the beginning of each period. CT, with and without glare, was at 0 and 60 days at three levels of visual angle. Lut + Zeax intake at baseline was 1.9 mg/day, and serum lutein was 0.36 µmol/L. Serum lutein increased 2.4-fold on day 15 (up to 0.81 and 0.90 µmol/L with free and ester lutein, respectively) and was maintained until the end of the study. Serum Zeax increased 1.7-fold. There were no differences in serum Lut responses to free or ester lutein at any time point. CT responses to lutein supplementation (free vs. ester) were not different at any time point. CT correlated with Lut under glare conditions, and better correlations were obtained at low frequencies in the whole group due to the older group. The highest correlations occurred between CT at high frequency and with glare with serum Lut and Lut + Zeax. Only in the older group were inverse correlations found at baseline at a high frequency with L + Z and with Lut/cholesterol and at a low frequency with Lut/cholesterol. In conclusion, daily supplementation with Lut for 15 days significantly increases serum Lut in normolipemic adults to levels associated with a reduced risk of age-related eye disease regardless of the chemical form of lutein supplied. Longer supplementation, up to two months, does not significantly alter the concentration achieved but may contribute to an increase in macular pigment (a long-term marker of lutein status) and thus improve the effect on visual outcomes.

Lutein as a high-value product from anaerobic digestate using the microalgae Chlorella vulgaris: Downstream processing and application in poultry

This study examined lutein production by microalgae (Chlorella vulgaris) using anaerobic digested as the substrate, its recovery and application in poultry. The influence of different electrodes, current density, and recovery time on the recovery of C. vulgarsis biomass and lutein by electrocoagulation flocculation was evaluated. C. vulgaris biomass recovery was maximum with copper and higher with aluminium electrodes at the current density 1.5 and 2.5 mA/cm2 respectively. The maximum lutein recovery after sonication was 95.42 % for biomass concentration of 33 mg/mL and treatment time of 4.5 min. Effect of different concentration of lutein (20 to100 mg/L) and molecular weight cut-off (600 to 1000 Da) of membrane on lutein recovery was investigated. Maximum lutein obtained was 89.34 % using 800–1000 Da filter. Lutein purity obtained was 83.36, 84.84, 84.32 and 72.02 % for the applied pressures 2, 3, 4 and 5 kg/cm2 respectively. Furthermore, lutein enhancement in egg yolk was demonstrated by supplementing lutein, lutein ester and microalgae at different concentrations (75 to 450 mg/kg) in the basal diet of chicken.

Quantitative Profiling of Carotenoids, Tocopherols, Phytosterols, and Fatty Acids in the Flower Petals of Ten Marigold (Tagetes spp. L.) Cultivars.

Marigold (Tagetes spp.) flower petals are the most vital sources of carotenoids, especially lutein esters, for the production of natural lutein to use for food, feed, and pharmaceutical industries. Several marigold cultivars are cultivated globally; however, their lutein ester composition and contents have not been widely investigated. Considering this, this study aimed to identify and quantify prominent carotenoid esters from the flower petals of ten marigold cultivars by liquid chromatography (LC)-diode-array detection (DAD)-mass spectrometry (MS). In addition, tocopherols, phytosterols, and fatty acids were analyzed by gas chromatography (GC)-flame ionization detection (FID) and GC-MS. Furthermore, the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS•+) and 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging abilities of lipophilic extracts were determined. The total carotenoid contents varied significantly (p < 0. 05, Tukey HSD) among cultivars, ranging from 25.62 (cv. Alaska)-2723.11 µg/g fresh weight (cv. Superboy Orange). Among the five major lutein-diesters, (all-E)-lutein-3-O-myristate-3'-O-palmitate and lutein dipalmitate were predominant. Among the studied cultivars, α-tocopherol was recorded, ranging from 167.91 (cv. Superboy Yellow) to 338.50 µg/g FW (cv. Taishan Orange). Among phytosterols, β-sitosterol was the most prevalent phytosterol, ranging between 127.08 (cv. Superboy Yellow) and 191.99 µg/g FW (cv. Taishan Yellow). Palmitic acid (C16:0; 33.36-47.43%) was the most dominant among the fatty acids. In this study, the highest contents of lutein were recorded from cv. Superboy Orange; however, due to the substantially higher flower petal yield, the cv. Durango Red can produce the highest lutein yield of 94.45 kg/ha. These observations suggest that cv. Durango Red and cv. Superboy Orange are the ideal candidates for lutein fortification in foods and also for commercial lutein extraction.

Utilization of red and yellow Coffea arabica var. Caturra pulp: macronutrient analysis, carotenoid extraction, and encapsulation for dairy product enrichment.

This study aimed to investigate the macronutrient and carotenoid content of red and yellow Coffea arabica var. Caturra pulp, a by-product of coffee processing in Colombia. The study employed ultra-sound-assisted extraction (UAE) to extract carotenoids, and a 23 factorial design was used to evaluate the effects of pulp color, biomass-solvent ratio, and solvent mixture composition on carotenoid content and extraction yield. The condition that provided the highest carotenoid extraction was further encapsulated by spray drying and added to a dairy product. The results showed that coffee pulp has significant dietary fiber content and high levels of carotenoids, with yellow pulp having a higher content than red pulp. Lutein isomers and lutein esters were the most abundant carotenoids found in both red and yellow coffee pulp. The highest carotenoid extraction was achieved using a 1:40 (g/mL) biomass:solvent ratio and a 20:80% v/v Ethanol:Ethyl Acetate solvent mixture for the yellow pulp. The carotenoid extract also demonstrated high encapsulation efficiency (46.57 ± 4.03%) and was found to be stable when added to a fermented milk product. This study presents an alternative solution for utilizing coffee by-products in Colombia, which could positively impact the families of over half a million Colombian coffee producers.

Specific Features of the Determination of Xanthophyll Esters under Reversed-Phase HPLC Conditions

Specific features of chromatographic determination of xanthophyll esters are studied using an example of marigold flower lutein diesters under reversed-phase HPLC conditions. The developed two-column method made it possible to establish that, in samples with a low solubility of carotenoids in the used solvent and on a chromatography column in using a mobile phase with a low solubility of carotenoids, the precipitation of diesters is possible, which detrimentally affects the accuracy of the chromatographic determination. A critical factor in this case isì temperature: the storage of samples (solutions) in a refrigerator is not always advisable, because freezing of the main components is possible. It was shown that the use of a mobile phase containing from 0 to 10 vol % acetonitrile in acetone at a temperature not lower than 20°C is acceptable for the separation of all-trans-lutein diesters from cis-derivatives of lutein and zeaxanthin derivatives on “monomeric” C18-phases.

Xanthophyll esterases in association with fibrillins control the stable storage of carotenoids in yellow flowers of rapeseed (Brassica juncea).

Biosynthesis, stabilization, and storage of carotenoids are vital processes in plants that collectively contribute to the vibrant colors observed in flowers and fruits. Despite its importance, the carotenoid storage pathway remains poorly understood and lacks thorough characterization. We identified two homologous genes, BjA02.PC1 and BjB04.PC2, belonging to the esterase/lipase/thioesterase (ELT) family of acyltransferases. We showed that BjPCs in association with fibrillin gene BjFBN1b control the stable storage of carotenoids in yellow flowers of Brassica juncea. Through genetic, high-resolution mass spectrometry and transmission electron microscopy analyses, we demonstrated that both BjA02.PC1 and BjB04.PC2 can promote the accumulation of esterified xanthophylls, facilitating the formation of carotenoid-enriched plastoglobules (PGs) and ultimately producing yellow pigments in flowers. The elimination of BjPCs led to the redirection of metabolic flux from xanthophyll ester biosynthesis to lipid biosynthesis, resulting in white flowers for B. juncea. Moreover, we genetically verified the function of two fibrillin genes, BjA01.FBN1b and BjB05.FBN1b, in mediating PG formation and demonstrated that xanthophyll esters must be deposited in PGs for stable storage. These findings identified a previously unknown carotenoid storage pathway that is regulated by BjPCs and BjFBN1b, while offering unique opportunities for improving the stability, deposition, and bioavailability of carotenoids.

Maternal High-Fat Diet Consumption in Sprague Dawley Rats Compromised the Availability and Altered the Tissue Distribution of Lutein in Neonatal Offspring.

Lutein, the most abundant carotenoid in the infant eye and brain, is critical for their visual and cognitive development. Due to its lipophilic nature, a high adiposity may affect the tissue distribution of lutein. The aim of the study was to determine the impacts of a maternal high-fat diet (HFD) consumption on the status of lutein in the neonatal offspring. Female Sprague Dawley rats (n = 6) were fed a normal fat diet (NFD) or a HFD for 8 weeks before mating, and they were switched to an NFD or an HFD containing the same concentration of lutein ester during gestation and lactation. Rat pups (n = 7/group/time) were euthanized on postnatal day 2 (P2), P6, P11, and P20 for measuring tissue lutein concentrations. No significant difference in maternal lutein intake was found between the two groups. At both P6 and P11, a significantly lower lutein concentration was noted in the milk samples separated from the stomach of HFD pups than the concentration in the samples from the NFD pups; the HFD group showed a significantly lower lutein concentration in the liver. At P11, the HFD pups exhibited a significantly lower lutein concentration in the eye, brain, and brown adipose tissue accompanied with a significantly higher lutein concentration and mass in the visceral white adipose tissue. The study was the first to provide evidence that maternal HFD consumption resulted in a compromised availability and altered distribution of lutein in the neonatal offspring.

Vitamin A, Vitamin E, and Carotenoid Concentrations in Livers of Marine Toads (Rhinella marina)

Global amphibian population decline is a major concern. Therefore, conservation centers have become increasingly needed for population sustainability breeding programs. This need makes proper nutrition programs while in human care imperative. The specific nutritional focus of this current research was to analyze vitamin A, vitamin E, and carotenoid (apocarotenoid, β-carotene, β-carotene ester, β-cryptoxanthin, lutein, lutein ester, zeaxanthin, and zeaxanthin ester) concentrations in the liver of 66 free-range marine toads (Rhinella marina) over a two-month period after entering human management. Toads were fed supplemented crickets randomly assigned to one of two diets: Diet 1 consisted of brown house crickets (Acheta domestica) gut loaded with Mazuri® Cricket Diet 5M38 and small amounts of sweet potato and carrots; Diet 2 consisted of an identical diet with the gut loaded crickets additionally dusted with Repashy® Superfoods Vitamin A Plus. Ten toads were euthanized prior to human management on Day 0 to assess baseline liver nutrients. Seven toads consuming each of the two diets (14 toads total) were euthanized on Days 9, 15, 32, and 62. Regardless of diet treatment, there were decreases (p &lt; 0.05) in all the analyzed nutrient concentrations over the 62-day human management period. The results from this study indicate that higher dietary vitamin A, vitamin E, and carotenoid content may be needed and/or the cricket gut loading and dusting techniques used to feed the amphibians food source insects may be inadequate.

Co-extraction of marigold flowers (Tagetes erecta L.) and dried coconut (Cocos nucifera L.) shreds using supercritical carbon dioxide: Characterization and functional food formulations

The present work was aimed at the valorization of marigold flowers collected from religious places. The marigold petal powders (MG) were used for the extraction of lutein, lutein esters (LEs), and total carotenoid esters (TCEs) using supercritical fluid extraction (SCFE) using carbon dioxide with dried coconut shreds (DC) in 1:2 (w/w) ratio. The optimized condition for co-extraction of MG and DC was 398 bar/60°C/149 min using Box-Behnken design. The yield (w/w) of the co-extract under the optimized conditions of SCFE was 35.49% (w/w). The SCFE co-extracts had higher DPPH antioxidant activities (126.39 µg AAE/mg sample vs. 89.48 µg AAE/mg sample in n-hexane extract) with similar trends being obtained for ABTS and FRAP assays, and better anti-inflammatory properties (60% vs. 55% inhibition in n-hexane extract compared to 75% by the standard drug, diclofenac). The SCFE co-extracts showed best stability at 5 °C. Hence, LEs and TCE rich extracts were used to formulate dairy and peanut butters, while the spent residue was used to formulate cookies with cocoa powder. The highest overall acceptability (7.69 on a 9-point hedonic scale) was seen in cookies containing 5% (w/w of the SCFE spent) and 4% (w/w) cocoa powder.

Process standardisation of fat replaced dietetic chhanakulfi using response surface methodology

Kulfi is an indigenous dairy product popular in northern part of India, often called the Indian ice-cream. It is a product that is relished by consumers of all ages and is gaining popularity in the current scenario. Kulfi’s high calorific value and sugar content make it unsuitable for diabetics and diet-conscious people. The present study was to optimize the preparation of fat replaced dietetic chhanakulfi by response surface methodology (RSM). It was prepared by using skim milk, low fat chhana, inulin (as fat mimetic), sucralose (as low-calorie sweetener) and lutein ester (as colourant and antioxidant). Based on preliminary trials the range of addition of inulin, low fat chhana, sucralose and lutein ester were selected as 3.3-8 per cent, 15-22.5 per cent, 200-300 ppm and 1.3-2.0 mg per 100gof the mix respectively. Computation of the optimised composition was done with these four variables and four responses consisting of sensory characteristics. The responses studied were flavour, body and texture, colour and appearance, overall acceptability using Central Composite Rotatable Design (CCRD) of RSM. The composition with highest desirability of 89 per centwas obtained for 6.34 per cent of inulin, 22.5 per cent, of low fat chhana, 243ppm of sucralose and 1.65mg lutein ester per 100g of the mix. The standardised product was analysed for its proximate composition which were, 1.22±0.25% fat, 9.26±0.66% protein and an energy value of 152±0.32kcal/g.Kulfi thus prepared had low calorie and was protein rich.

A xanthophyll-derived apocarotenoid regulates carotenogenesis in tomato chromoplasts

Carotenoids possess important biological functions that make them essential components of the human diet. β-Carotene and some other carotenoids have vitamin A activity while lutein and zeaxanthin, typically referred to as the macular pigments, are involved in good vision and in delaying the onset of age-related eye diseases. In order to create a zeaxanthin-producing tomato fruit, two transgenic lines, one with a high β-carotene cyclase activity and the other with a high β-carotene hydroxylase activity, have been genetically crossed. Ripe fruits from the resulting progeny contained significant levels of violaxanthin, antheraxanthin, and xanthophyll esters. However, their zeaxanthin content was not as high as expected, and the total level of carotenoids was only 25% of the carotenoids found in ripe fruits of the comparator line. Targeted transcript analysis and apocarotenoids determinations indicated that transcriptional regulation of the pathway or degradation of synthesized carotenoids were not responsible for the low carotenoid content of hybrid fruits which instead appeared to result from a substantial reduction of carotenoid biosynthesis. Notably, the content of an unidentified hydroxylated cyclic (C13) apocarotenoid was 13 times higher in the hybrid fruits than in the control fruits. Furthermore, a GC-MS-based metabolite profiling demonstrated a perturbation of carotenogenesis in ripening hybrid fruits compatible with a block of the pathway. Moreover, carotenoid profiling on leaf, fruit, and petal samples from a set of experimental lines carrying the hp3 mutation, in combination with the two transgenes, indicated that the carotenoid biosynthesis in petal and fruit chromoplasts could be regulated. Altogether the data were consistent with the hypothesis of the regulation of the carotenoid pathway in tomato chromoplasts through a mechanism of feedback inhibition mediated by a xanthophyll-derived apocarotenoid. This chromoplast-specific post-transcriptional mechanism was disclosed in transgenic fruits of HU hybrid owing to the abnormal production of zeaxanthin and antheraxanthin, the more probable precursors of the apocarotenoid signal. A model describing the regulation of carotenoid pathway in tomato chromoplasts is presented.

Lutein bioaccessibility in casein-stabilized emulsions is influenced by the free to acylated carotenoid ratio, but not by the casein aggregation state

Considering that carotenoids are found acylated to fatty acids in most edible fruits, the influence of the ratio of free to acylated lutein on the hydrolysis extent and bioaccessibility was evaluated by in vitro digestion. For this purpose, for the first time, esterified, free, or a mixture of both carotenoid forms was used in the lipid phase of emulsions stabilized by sodium caseinate (NaCas) and native phosphocaseinate (PPCN). Marigold petals was used as a source of lutein-rich extracts. The emulsions were characterized and the extent of ester hydrolysis, carotenoid recovery, and bioaccessibility were evaluated by LC-DAD-MS/MS. Besides low polydispersity, NaCas and PPCN stabilized emulsions exhibited a constant mean droplet diameter of about 260 and 330 nm, respectively, after 7 days. Caseins were completely digested after the gastric digestion step. Moreover, casein supramolecular structure did not significantly affect carotenoid bioaccessibility. Lutein was majorly found in its free form in all bioaccessible fractions. The carotenoid bioaccessibility increased from 3% to 40% by increasing the percentage of free carotenoids from 0.5 to 100% in the emulsions; but the carotenoid recovery and hydrolysis extent of lutein esters were not affected. In conclusion, emulsion-based systems for carotenoid delivery stabilized either by NaCas or PPCN provided similar carotenoid bioaccessibility. Furthermore, bioaccessibility was inversely dependent on the overall hydrophobicity of the carotenoid extract. Our results suggest that the low bioaccessibility of esterified carotenoids was a consequence of their limited hydrolysis extent. This study provides information that may help design emulsion-based systems stabilized by food protein as a vehicle for carotenoids.

Type I diacylglycerol acyltransferase (DGAT1) from the unicellular green alga Haematococcus pluvialis is a xanthophyll acyltransferase

Xanthophyll esters are present in a large number of plants and microalgae, but its biosynthesis process is poorly understood. We demonstrated that acylation of xanthophylls is catalyzed by type I diacylglycerol acyltransferase (DGAT) from the unicellular green alga Haematococcus pluvialis. Expression of HpDGAT1, and three of the four HpDGAT2 genes showed significant up-regulation under all the three adverse environmental conditions to trigger astaxanthin esters biosynthesis, respectively. Addition of recombinant HpDGAT1 into the enzymatic assay system with the endoplasmic reticulum membranes of H. pluvialis as the enzyme sources further significantly increased net xanthophyll esters formation. Overexpressing HpDGAT1 in an engineered Escherichia coli strain capable of producing free astaxanthin led to enhanced accumulation of both free astaxanthin and xanthophyll esters with maximum UV absorption at 480 nm, the typical feature of astaxanthin esters. Application of DGAT1 specific inhibitor A922500 decreased the content of astaxanthin esters up to 36% in H. pluvialis under high light stress. These data suggested that HpDGAT1 act as xanthophyll acyltransferase in H. pluvialis. Our findings broaden the understanding of xanthophylls acylation in microalgae.

Effect of Ultrasound-Assisted Extraction of Carotenoids from Papaya (Carica papaya L. cv. Sweet Mary) Using Vegetable Oils

By-products from fruits and are of great interest for their potential use in the food industry due to their high content of bioactive compounds. Herein, we examined the ultrasound-assisted extraction (UAE) of carotenoid and carotenoid esters from papaya pulp and peel using soybean oil and sunflower oil as alternative green solvents. Response surface methodology (RSM) was established to optimize the UAE process. Three independent variables, ultrasonic amplitude (20–60%), time (10–60 min), and co-solvent percentage (ethanol) (5–20%, v/v), were applied. The highest total carotenoid content in the UAE extracts was obtained from papaya pulp extracts (58.7 ± 1.6 and 56.0 ± 1.5 μg carotenoids/g oil) using soybean oil and sunflower oil, respectively (60% amplitude/ 10 min/ 20% ethanol). On the other hand, the highest carotenoid content (52.0 ± 0.9 μg carotenoids/g oil) was obtained from papaya peel using soybean oil applying the UAE process (20% amplitude/ 77 min/ 20% ethanol); a minor content of 39.3 ± 0.5 μg carotenoids/g oil was obtained from papaya peel using sunflower oil at 60% amplitude/ 60 min/ 5% ethanol. Lycopene was the most abundant carotenoid among all individual carotenoids observed in papaya oil extracts, obtaining the highest yields of this carotenoid when papaya pulp and peel were extracted using soybean oil (94% and 81%, respectively) and sunflower oil (95% and 82%, respectively). Great extraction of xanthophyll esters was detected using 20% of ethanol in the vegetable oil extraction solvent (v/v). High correlations (>0.85) was obtained between total carotenoid content and color determination in the UAE oil extracts. UAE vegetable oil extracts enriched with carotenoids from papaya by-products could be useful to formulate new food ingredients based on emulsions with interesting potential health benefits.

The breeder's tool-box for enhancing the content of esterified carotenoids in wheat: From extraction and profiling of carotenoids to marker-assisted selection of candidate genes.

Carotenoid esterification is a new target for cereal biofortification since esterification increases both accumulation and stability of carotenoids. A xanthophyll acyl transferase is responsible for carotenoid esterification in the endosperm of wheat and related cereals. In this chapter we describe the procedures for transferring the carotenoid esterification attribute into wheat using the wild barley Hordeum chilense as donor of the esterification trait, the outline of the breeding program and the protocols for marker assisted selection and the analysis of carotenoids in grain. Biofortified cereals with increased lutein ester content will help to reduce the risk of developing age-related macular degeneration in human populations with limited access to other dietary sources.

Enzymatic acylation of lutein with a series of saturated fatty acid vinyl esters and the thermal stability and anti-lipid oxidation properties of the acylated derivatives.

Lutein was enzymatically acylated with saturated fatty acid vinyl esters of different lengths of carbon chain (C6 -C14 ) under the action of Candida antarctica lipase B (Novozyme 435). The acylation reaction was optimized by considering substrate molar ratio, reaction solvent, type of enzyme, and reaction time. The highest yield (88%) was obtained using the Novozyme 435 to catalyze the acylation reaction of lutein and vinyl decanoate (lutein/vinyl decanoate molar ratio of 1/10) for 16 h in methyl tert-butyl ether. Ten lutein esters were synthesized, isolated, and purified, which were characterized by Fourier-transform infrared spectroscopy, high-resolution mass spectrometry, and nuclear magnetic resonance spectroscopy. We found that the acylation of lutein improved its antioxidant capacity in lipid system and thermal stability. Our study extended the potential application of lutein in lipophilic food, cosmetic, and pharmaceutical industries. Practical Application: Enzyme acylation of lutein improved its antioxidant capacity in lipid system and thermal stability, extended its potential application in food, cosmetic, and pharmaceutical industries. In addition, our study also provided a new perspective and cognition for the further development and utilization of lutein.

Interaction of ovalbumin with lutein dipalmitate and their effects on the color stability of marigold lutein esters extracts

In this study, the interaction of ovalbumin with lutein dipalmitate and the effect of ovalbumin on marigold lutein esters extracts were investigated. Lutein dipalmitate quenched the fluorescence of ovalbumin by static quenching. Binding and thermodynamic parameters proved that lutein dipalmitate bound to ovalbumin spontaneously by van der Waals force and hydrogen bond, and the complex stoichiometry was 1:1. Through three-dimensional fluorescence spectroscopy, Fourier transform infrared spectroscopy and circular dichroism experiments, the conformation of ovalbumin was unfolded, and alteration in the ovalbumin secondary structure induced by lutein dipalmitate was observed. The results of transmission electron microscopy and particle size revealed that there were spherical and nano-sized aggregates in the ovalbumin-lutein dipalmitate system, indicating the lutein dipalmitate not only could bind to ovalbumin at molecular level, but also promote the aggregation of ovalbumin. Additionally, the addition of ovalbumin had a positive effect on the stability of marigold lutein esters extracts.