Identification of zeinoxanthin in orange juices

Screening for Innovative Sources of Carotenoids and Phenolic Antioxidants among Flowers

Flowers have been used for centuries in decoration and traditional medicine, and as components of dishes. In this study, carotenoids and phenolics from 125 flowers were determined by liquid chromatography (RRLC and UHPLC). After comparing four different extractants, the carotenoids were extracted with acetone: methanol (2:1), which led to a recovery of 83%. The phenolic compounds were extracted with 0.1% acidified methanol. The petals of the edible flowers Renealmia alpinia and Lantana camara showed the highest values of theoretical vitamin A activity expressed as retinol activity equivalents (RAE), i.e., 19.1 and 4.1 RAE/g fresh weight, respectively. The sample with the highest total phenolic contents was Punica granatum orange (146.7 mg/g dry weight). It was concluded that in most cases, flowers with high carotenoid contents did not contain high phenolic content and vice versa. The results of this study can help to develop innovative concepts and products for the industry.

Expression and functional analysis of citrus carotene hydroxylases: unravelling the xanthophyll biosynthesis in citrus fruits

BACKGROUND

Xanthophylls are oxygenated carotenoids and fulfill critical roles in plant growth and development. In plants, two different types of carotene hydroxylases, non-heme di-iron and heme-containing cytochrome P450, were reported to be involved in the biosynthesis of xanthophyll. Citrus fruits accumulate a high amount of xanthophylls, especially β,β-xanthophylls. To date, however, the roles of carotene hydroxylases in regulating xanthophyll content and composition have not been elucidated.

RESULTS

In the present study, the roles of four carotene hydroxylase genes (CitHYb, CitCYP97A, CitCYP97B, and CitCYP97C) in the biosynthesis of xanthophyll in citrus fruits were investigated. Phylogenetic analysis showed that the four citrus carotene hydroxylases presented in four distinct clusters which have been identified in higher plants. CitHYb was a non-heme di-iron carotene hydroxylase, while CitCYP97A, CitCYP97B, and CitCYP97C were heme-containing cytochrome P450-type carotene hydroxylases. Gene expression results showed that the expression of CitHYb increased in the flavedo and juice sacs during the ripening process, which was well consistent with the accumulation of β,β-xanthophyll in citrus fruits. The expression of CitCYP97A and CitCYP97C increased with a peak in November, which might lead to an increase of lutein in the juice sacs during the ripening process. The expression level of CitCYP97B was much lower than that of CitHYb, CitCYP97A, and CitCYP97C in the juice sacs during the ripening process. Functional analysis showed that the CitHYb was able to catalyze the hydroxylation of the β-rings of β-carotene and α-carotene in Escherichia coli BL21 (DE3) cells. Meanwhile, when CitHYb was co-expressed with CitCYP97C, α-carotene was hydroxylated on the β-ring and ε-ring sequentially to produce lutein.

CONCLUSIONS

CitHYb was a key gene for β,β-xanthophyll biosynthesis in citrus fruits. CitCYP97C functioned as an ε-ring hydroxylase to produce lutein using zeinoxanthin as a substrate. The results will contribute to elucidating xanthophyll biosynthesis in citrus fruits, and provide new strategies to improve the nutritional and commercial qualities of citrus fruits.

In vitro bioaccessibility of carotenoids, flavonoids, and vitamin C from differently processed oranges and orange juices [Citrus sinensis (L.) Osbeck]

Carotenoid, flavonoid, and vitamin C concentrations were determined in fresh orange segments and a puree-like homogenate derived thereof, as well as freshly squeezed, flash-pasteurized, and pasteurized juices. Lutein and β-cryptoxanthin were slightly degraded during dejuicing, whereas β-carotene levels were retained. Vitamin C levels remained unaffected, whereas flavonoid levels decreased 8-fold upon juice extraction, most likely due to the removal of flavonoid-rich albedo and juice vesicles. Likewise, the presence of such fibrous matrix compounds during in vitro digestion was assumed to significantly lower the total bioaccessibility (BA) of all carotenoids from fresh fruit segments (12%) as compared to juices (29-30%). Mechanical disruption of orange segments prior to digestion did not alter carotenoid BA, whereas pasteurization of the freshly squeezed juice slightly increased BA by 9-11%. In addition to carotenoid BA, the stabilities of hesperidin, narirutin, and vitamin C including dehydroascorbic acid during in vitro digestion were monitored, and applied analytical methods were briefly validated.

Determination of carotenoids, total phenolic content, and antioxidant activity of Arazá (Eugenia stipitata McVaugh), an Amazonian fruit

The fruit of Arazá (Eugenia stipitata McVaugh) native to the Colombian Amazon is considered a potentially economically valuable fruit for the Andean economy due to its novel and unique taste. The fruit has an intense yellow color, but its chemical composition and properties have not been well studied. Here we report the identification and quantitation of carotenoids in the ripe fruit using high performance liquid chromatography (HPLC) with photodiode array detector (PDA) and atmospheric pressure chemical ionization (APcI) mass spectrometry (MS/MS). The qualitative carotenoid profile of the fruit according to maturity stage was also observed. Furthermore, antioxidant activity of the peel and pulp were assessed using the ferric reducing ability of plasma (FRAP), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and 1,1-diphenyl-2-picrylhydrazyl (DPPH) methods, in addition to chemical indexes and total phenolic content. Multiple carotenoids were identified in the peel and pulp including four xanthophylls (free and esterified as their mono and diesters) and two carotenes. One of the xanthophylls was tentatively identified as zeinoxanthin, while the others were identified as lutein, zeaxanthin, and β-cryptoxanthin. Carotenes included α-carotene and β-carotene. The total carotenoid content was significantly higher in the peel (2484 ± 421 μg/100 g FW) than in the pulp (806 ± 348 μg/100 g FW) with lutein, β-cryptoxanthin, and zeinoxanthin as the major carotenoid components. The unique carotenoid composition of this fruit can differentiate it from other carotenoid-rich fruits and perhaps be useful in authentication procedures. Overall, results from this study suggest that Colombian Arazá may be a good edible source of carotenoids important in retinal health as well as carotenoids with provitamin A activity. Therefore, Arazá fruit can be used as a nutraceutical ingredient and in production of functional foods in the Colombian diet.

Epoxycarotenoids esters analysis in intact orange juices using two-dimensional comprehensive liquid chromatography

In this work, the native carotenoid pattern of different orange juices was studied by LC x LC-DAD/APCI-IT-TOF-MS for the first time. Special attention was given to the epoxycarotenoids components. It has been already proposed that the relative proportions and composition of these epoxycarotenoids can be used to estimate the age and freshness of an orange juice. Re-arrangements from 5,6- to 5,8-epoxides can occur with time, partially due to the natural acidity of the juices. Thus, the study of these carotenoids in their intact form, that is, esterified with fatty acids, is of great interest. Besides, other free carotenoid and carotenoids esters were identified in seven different monovarietal orange juices and a commercial orange juice. Moreover, the higher separation power of the present LC x LC approach allowed a clearer identification of the compounds contained in the sample compared to the more commonly used approach which uses C(30) stationary phases in conventional LC, thanks to the attainment of clearer MS spectra due to the higher resolution and separation degree obtained in LC x LC. This method could also be used to establish authenticity markers among orange varieties that could be potentially used to prevent or detect adulterations or to establish ripeness indexes.

Changes in carotenoid content and biosynthetic gene expression in juice sacs of four orange varieties (Citrus sinensis) differing in flesh fruit color

The contribution of carotenoid composition to the color range of the fruit juice sacs of four orange varieties (Citrus sinensis) differing in flesh color, namely, Shamouti (normal orange color), Sanguinelli ("blood cultivar" purple color), Cara Cara navel (pink-reddish), and Huang pi Chen (yellowish color), was investigated. To this end, qualitative and quantitative analyses of carotenoid contents were first performed by high-performance liquid chromatography (HPLC) using a C30 column and a photodiode array detector in February, at a late developmental fruit stage. Concomitantly, transcript levels of Dxs, the gene controlling the first step of the MEP pathway, and six genes involved in beta,beta-xanthophyll biosynthesis (Psy, Pds, Zds, Lcy-b, Hy-b, and Zep) were determined in August, November, and February. Transcript level measurement was carried out by real-time RT-PCR on total RNA from juice sacs. The four orange varieties displayed different carotenoid profiles. Shamouti and Sanguinelli oranges accumulated mainly beta,beta-xanthophylls as expected in typically colored oranges, whereas Cara Cara navel orange accumulated linear carotenes in addition to cis-violaxanthin. Huang pi Chen fruit flesh orange was characterized by a strong reduction of total carotenoid content. Whereas gene expression was relatively low and similar in August (before color break) in all four varieties, in November (during color break), Dxs, Zds, Hy-b, and Zep expression was higher in Cara Cara and Huang pi Chen oranges. The beta,beta-xanthophyll accumulation observed in February in Shamouti and Sanguinelli oranges was apparently related to the increase of transcript levels of all measured genes (i.e., Dxs, Psy, Pds, Zds, Hy-b, and Zep) except Lcy-b. At this time, however, transcript levels in Cara Cara were rather similar to those found in Sanguinelli, although both showed different carotenoid compositions. The Huang pi Chen phenotype correlated with lower expression of Dxs and Psy genes. These results revealed a general pattern of transcript change in juice sacs of citrus fruit, characterized by an apparent coordination of Dxs and Psy expression and a general increase in mRNA levels of carotenoid biosynthetic genes. These transcript changes correlated well with the beta,beta-xanthophyll accumulation, the normal carotenoid set, observed in Shamouti and Sanguinelli oranges and suggest that the preferential accumulation of linear carotenes in Cara Cara navel and the practical absence of carotenoids in Huang pi Chen oranges were not predominantly due to changes in regulation of carotenoid biosynthetic genes at the transcriptional level.

HPLC-PDA-MS/MS of anthocyanins and carotenoids from dovyalis and tamarillo fruits

Anthocyanins and carotenoids are natural pigments responsible for the color of vegetables and fruits, and they are also bioactive compounds, both demonstrating important biological, therapeutic, and preventative properties. Considering the biodiversity of edible fruits, high performance liquid chromatography coupled to photodiode array and mass spectrometry detectors (HPLC-PDA-MS) was used to establish the composition of carotenoids and anthocyanins from dovyalis and tamarillo fruits. Ten anthocyanins and 26 carotenoids were found in dovyalis, whereas tamarillo showed 3 anthocyanins and 17 carotenoids. Higher contents of anthocyanins and carotenoids were found in dovyalis, 42.0 and 6.6 mg/100 g, respectively, as compared to tamarillo fruits with 8.5 and 4.4 mg/100 g, respectively. Although these fruits belong to different families, delphinidin 3-rutinoside and beta-cryptoxanthin were found to be, respectively, the major anthocyanin and carotenoid in both fruits.

Plasma responses in human subjects after ingestions of multiple doses of natural alpha-cryptoxanthin: a pilot study

Xanthophylls have attracted a lot of interest since their health benefits were documented. Unfortunately, studying their intestinal absorption is often affected by high baseline levels present in the fasting plasma. As alpha-cryptoxanthin is rarely found in the traditional European diet, its concentration in human plasma is extremely low. A pilot human intervention study was designed using alpha-cryptoxanthin for the first time as a marker xanthophyll in a minimally formulated cellulose-based supplement. Alpha-cryptoxanthin was administered in gelatin soft-gel capsules in multiple doses of 156 microg/d to three male volunteers (age 27.3 (SD 4.7) years; BMI 21.6 (SD 0.3) kg/m(2)) for 16 d after a 2-week carotenoid depletion period. Fasting blood samples were taken before the intervention and after 3, 6, 9, 13 and 16 d. Plasma HPLC analyses allowed for determination of the concentration; liquid chromatography-MS in the single ion monitoring mode was used to confirm peak assignment. The concentrations of alpha-cryptoxanthin increased significantly after only 3 d of supplementation. The concentration-time plots showed a characteristic shape with a first maximum after day 6, a decline until day 9 and a gradual second rise until the end of the study. Standardisation of plasma alpha-cryptoxanthin concentrations to triacylglycerol or total cholesterol did not influence the characteristics. The maximum concentrations reached at the end of the intervention period ranged from 0.077 to 0.160 micromol/l. These results suggest a high intestinal absorption and an enrichment of alpha-cryptoxanthin in the plasma even from a minimally formulated cellulose-based supplement.