Role of the cultivar in choosing Clementine fruits with a high level of health-promoting compounds

Thirteen cultivars and two hybrids of Clementine fruits (Citrus clementina Hort. Ex. Tan) cultivated in Italy were characterized according to pH, titratable acidity, total soluble solids, total polyphenols, carotenoids, vitamin C, hesperidin, rutin, narirutin and naringin and radical scavenging activity. The presence of rutin in Clementine fruit juice is reported for the first time here. The results indicated that all chemical parameters statistically differentiated each cultivar (P < 0.001). In particular, principal component analysis showed a clear discrimination of five cultivars from all the other varieties based on vitamin C and total polyphenols for the Caffin cultivar, which showed also the highest antioxidant activity; narirutin for the Etna hybrid cultivar; hesperidin, rutin and total soluble solids for the SRA 89 cultivar; and naringin, hesperidin and rutin for the Esbal cultivar. Moreover, the Mandalate hybrid cultivar showed the lowest antioxidant activity as well as vitamin C and total polyphenols content, while titratable acidity and naringin level were the highest. The antioxidant activity assessed in all the fruits was closely correlated with vitamin C and total polyphenols content, rather than with the flavonoid compounds.     

Thermal degradation of antioxidant micronutrients in citrus juice: kinetics and newly formed compounds

The thermal degradation kinetics of vitamin C, two carotenoids (beta-carotene and beta-cryptoxanthin), and hesperidin, as a function of temperature, were determined for Citrus juice [Citrus sinensis (L.) Osbeck and Citrus clementina Hort. ex Tan]. The influence of dissolved oxygen on the rate of ascorbic acid degradation was also assessed. Analysis of kinetic data suggested a first-order reaction for the degradation of vitamin C and carotenoids. The kinetics parameters Dtheta, z, and Ea have been calculated. Following the Arrhenius relationship, the activation energy of ascorbic acid was 35.9 kJ mol-1 and agreed with the range of literature reported value. The results on vitamin C and carotenoids from citrus juice made it possible to validate the predicting model. Thermal degradation of carotenoids revealed differences in stability among the main provitamin A carotenoids and between these and other carotenoids belonging to the xanthophyll family. The activation energies for the two provitamin A carotenoids were 110 and 156 kJ mol-1 for beta-carotene and beta-cryptoxanthin, respectively. On the other hand, no degradation of hesperidin was observed during thermal treatment. Finally, the vitamin C in citrus juice was not as heat sensitive as expected and the main provitamin A carotenoids present in citrus juice displayed a relative heat stability. The high-performance liquid chromatography-diode array detection-mass spectrometry analysis of degradation products showed that the isomerization of the epoxide function in position 5,6 into a furanoxide function in position 5,8 was a common reaction for several xanthophylls. These findings will help determine optimal processing conditions for minimizing the degradation of important quality factors such as vitamin C and carotenoid in citrus juice.     

Orange, mandarin, and hybrid classification using multivariate statistics based on carotenoid profiles

A study was undertaken to differentiate citrus on the basis of a carotenoid profile obtained from the HPLC determination of 12 carotenoids found in saponified fresh juice. Mandarin, orange, and various hybrid varieties were analyzed to determine their carotenoid profiles. The resulting peak areas were analyzed using principal component analysis (PCA), canonical discriminate analysis (CDA), and Mahalanobis distances. These were used to develop models for classifying the juices into appropriate groups. Thirty-two samples were analyzed to determine classification techniques. Mandarin and orange juices were quite distinct, with the hybrids scattered throughout the mandarin and orange clusters using PCA. CDA resulted in three distinct groups with only a few of the hybrids in the orange grouping.     

Evaluation of auraptene content in citrus fruits and their products

Auraptene quantities in Tanaka's 77 Citrus species (including 14 varieties and cultivars), 5 Fortunella species, one Poncirus species, 27 hybrids between Citrus species, and 51 intergeneric hybrids between Citrus and Poncirus have been evaluated. The genus Citrus has been divided into eight groups. Auraptene is found in all of the species of Cephalocitrus group, a part of the species of Aurantium group, and most of the species of Osmocitrus group. The Citrus species contain a small amount of auraptene in the juice sacs compared with in the peels except for Henka mikan (C. pseudo-aurantium), Ichang lemon (C. wilsonii), and a Hassaku (C. hassaku)-pummelo hybrid (Okitsu No. 39), which contain large quantities of auraptene in their juice sacs (0.23, 0.52, and 0.14 mg/g, respectively). The Hong Kong wild kumquat (F. hindusii) alone contains auraptene in Fortunella species. All of the Citrus-trifoliate orange (P. trifoliata) hybrids as well as the trifoliate orange contain a large quantity of auraptene in both the peel (16.57-0.51 mg/g) and the juice sac (10.32-0.15 mg/g). These hybrids are almost inedible. The Iyo (C. iyo)-trifoliate orange hybrid (IyP269) is edible and contains auraptene in the peel (1.49 mg/g) and in the juice sac (1.73 mg/g). Citrus fruit products, for example, brand-named grapefruit juice and marmalade, retain about 0. 1 mg and 0.3 mg/100 g of auraptene, respectively.     

Carotenoid diversity in cultivated citrus is highly influenced by genetic factors

Citrus fruits are complex sources of carotenoids with more than 100 kinds of pigments reported in this genus. To understand the origin of the diversity of carotenoid compositions of citrus fruit, 25 genotypes that belong to the 8 cultivated Citrus species were analyzed. Juice extracts of mature fruit were analyzed by high-performance liquid chromatography using a C30 column. The 25 citrus genotypes presented different carotenoid profiles with 25 distinct compounds isolated. Statistical analyses revealed a strong impact of genotype on carotenoid compositions. Two kinds of classifications of genotypes were performed: on qualitative data and on quantitative data, respectively. The results showed that variability in carotenoid compositions was more interspecific than intraspecific. Two carotenoids, cis-violaxanthin and the beta-cryptoxanthin, strongly determined the classification on qualitative data, which was also in agreement with previous citrus variety classifications. These findings provide evidence that, as for other phenotypical traits, the general evolution of cultivated Citrus is the main factor of the organization of carotenoid diversity among citrus varieties. To the authors' knowledge this is the first study that links the diversity of carotenoid composition to the citrus genetic diversity. These results lead to the proposed major biosynthetic steps involved in the differential carotenoid accumulation. Possible regulation mechanisms are also discussed.     

Carotenoids in white- and red-fleshed loquat fruits

Fruits of 23 loquat ( Eriobotrya japonica Lindl.) cultivars, of which 11 were white-fleshed and 12 red-fleshed, were analyzed for color, carotenoid content, and vitamin A values. Color differences between two loquat groups were observed in the peel as well as in the flesh. beta-Carotene and lutein were the major carotenoids in the peel, which accounted for about 60% of the total colored carotenoids in both red- and white-fleshed cultivars. beta-Cryptoxanthin and, in some red-fleshed cultivars, beta-carotene were the most abundant carotenoids in the flesh, and in total, they accounted for over half of the colored carotenoids. Neoxanthin, violaxanthin, luteoxanthin, 9- cis-violaxanthin, phytoene, phytofluene, and zeta-carotene were also identified, while zeaxanthin, alpha-carotene, and lycopene were undetectable. Xanthophylls were highly esterified. On average, 1.3- and 10.8-fold higher levels of colored carotenoids were observed in the peel and flesh tissue of red-fleshed cultivars, respectively. The percentage of beta-carotene among colored carotenoids was higher in both the peel and the flesh of red-fleshed cultivars. Correlations between the levels of total colored carotenoids and the color indices were analyzed. The a* and the ratio of a*/ b* were positively correlated with the total content of colored carotenoids, while L*, b*, and H degrees correlated negatively. Vitamin A values, as retinol equivalents (RE), of loquat flesh were 0.49 and 8.77 microg/g DW (8.46 and 136.41 microg/100 g FW) on average for white- and red-fleshed cultivars, respectively. The RE values for the red-fleshed fruits were higher than fruits such as mango, red watermelon, papaya, and orange as reported in the literature, suggesting that loquat is an excellent source of provitamin A.     

Variation in major antioxidants and total antioxidant activity of Yuzu (Citrus junos Sieb ex Tanaka) during maturation and between cultivars

Epidemiological studies suggest that a high consumption of fruits can reduce the risk of some cancers and cardiovascular disease, and this may be attributable to the antioxidant activity of vitamins and phenolic compounds. The present study investigated the variations in vitamin C, total phenolic, hesperidin, and naringin contents, and total antioxidant activity of yuzu (Citrus junos Sieb ex Tanaka)-which is a popular citrus fruit in Korea and Japan-between cultivars and during maturity. The amounts of phenolics and vitamin C and the antioxidant activity in all tested yuzu cultivars were higher in peel than in flesh. Ripening increased the total antioxidant activity and vitamin C content in both peel and flesh of yuzu. However, the amounts of all total phenolics, hesperidin, and naringin in peel increased with ripening, whereas they decreased slightly in flesh. There was a highly linear relationship between the vitamin C content and the total antioxidant activity in both peel (r(2) = 1.000) and flesh (r(2) =0.998), suggesting that vitamin C plays a key role in the antioxidant activity of yuzu. In addition, the contribution of each antioxidant to the total antioxidant activity of yuzu was determined using a 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging assay and is expressed here in terms of the vitamin C equivalent antioxidant capacity (VCEAC). The means of vitamin C, naringin, and hesperidin in yuzu were 90.4, 63.8, and 65.7 mg/100 g fresh yuzu, respectively. The relative VCEAC values of these compounds were in the following order: vitamin C (1.00) > naringin (0.195) > hesperidin (0.162). Therefore, the estimated contribution of each antioxidant to the total antioxidant capacity of 100 g of fresh yuzus is as follows (in mg of VCEAC): vitamin C (90.36 mg) > naringin (12.44 mg) > hesperidin (10.64 mg). Our results indicate that mature yuzu contains higher amounts of vitamin C and phenolics than other citrus fruits and could therefore be used as a significant dietary source of antioxidants.     

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 beta- and alpha-carotene, beta-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 microg beta-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.     

Effects of blood orange juice intake on antioxidant bioavailability and on different markers related to oxidative stress

Orange juice is a source of antioxidants that might afford in vivo protection from oxidative stress. To test this hypothesis, we carried out a human intervention study with blood orange juice containing high amounts of vitamin C, anthocyanins, and carotenoids. Sixteen healthy female volunteers were enrolled in a crossover study and were given 600 mL/day of blood orange juice or a diet without juice for 21 days. Before and after each intervention period, plasma vitamin C, cyanidin-3-glucoside, and carotenoids were quantified. Furthermore, plasma antioxidant capacity, malondialdehyde concentration in plasma, 11-dehydrotromboxane B(2) urinary excretion, and lymphocyte DNA damage were evaluated as biomarkers of oxidative stress. Blood orange juice consumption determined a significant increase in plasma vitamin C, cyanidin-3-glucoside, beta-cryptoxanthin, and zeaxanthin. Also, lymphocyte DNA resistance to oxidative stress was improved whereas no effect was observed on the other markers that we analyzed. In turn, these results suggest that blood orange juice is a bioavailable source of antioxidants, which might moderately improve the antioxidant defense system; however, the long-term effects of its consumption are to be further investigated.     

Quantification of carotenoids in citrus fruit by LC-MS and comparison of patterns of seasonal changes for carotenoids among citrus varieties

To quantify the 18 carotenoids on the basic routes of the carotenoid biosynthesis in plants simultaneously, a method for liquid chromatography-mass spectrometry (LC-MS) using atmospheric pressure chemical ionization was developed. With this method, the seasonal changes of carotenoids in the flavedo and juice sacs of 39 citrus varieties were analyzed. On the basis of the patterns of seasonal changes of carotenoids in both flavedo and juice sacs, 39 citrus varieties were classified. In flavedo, 39 varieties were classified into 5 clusters, in which the carotenoid profiles were carotenoid-poor, phytoene-abundant, violaxanthin-abundant, violaxanthin- and beta-cryptoxanthin-abundant, and phytoene-, violaxanthin-, and beta-cryptoxanthin-abundant, respectively. In juice sacs, they were classified into 4 clusters, in which the carotenoid profiles were carotenoid-poor, violaxanthin-abundant, violaxanthin- and phytoene-abundant, and violaxanthin-, phytoene-, and beta-cryptoxanthin-abundant, respectively. In flavedo, many citrus varieties, except for the carotenoid-poor and phytoene-abundant varieties, massively accumulated beta,epsilon-carotenoids (e.g., lutein), beta,beta-carotenoids (e.g., beta-cryptoxanthin and violaxanthin), and phytoene, in that order. In juice sacs, the accumulation order among beta,beta-carotenoids was observed. Violaxanthin accumulation preceded beta-cryptoxanthin accumulation in violaxanthin-, phytoene-, and beta-cryptoxanthin-abundant varieties. In each variety, the carotenoid profiles of the flavedo and juice sacs on the basis of the concentration in violaxanthin and beta-cryptoxanthin were similar, with the exception of a few varieties.     

Carotenoids and carotenoid esters in potatoes (Solanum tuberosum L.): new insights into an ancient vegetable

The carotenoid pattern of four yellow- and four white-fleshed potato cultivars (Solanum tuberosum L.), common on the German market, was investigated using HPLC and LC(APCI)-MS for identification and quantification of carotenoids. In each case, the carotenoid pattern was dominated by violaxanthin, antheraxanthin, lutein, and zeaxanthin, which were present in different ratios, whereas neoxanthin, beta-cryptoxanthin, and beta,beta-carotene generally are only minor constituents. In contrast to literature data, antheraxanthin was found to be the only carotenoid epoxide present in native extracts. The total concentration of the four main carotenoids reached 175 microg/100 g, whereas the sum of carotenoid esters accounted for 41-131 microg/100 g. Therefore, carotenoid esters are regarded as quantitatively significant compounds in potatoes. For LC(APCI)-MS analyses of carotenoid esters, a two-stage cleanup procedure was developed, involving column chromatography on silica gel and enzymatic cleavage of residual triacylglycerides by lipases. This facilitated the direct identification of several potato carotenoid esters without previous isolation of the compounds. Although the unequivocal identification of all parent carotenoids was not possible, the cleanup procedure proved to be highly efficient for LC(APCI)-MS analyses of very low amounts of carotenoid esters.     

Carotenoid esters in vegetables and fruits: a screening with emphasis on beta-cryptoxanthin esters

Carotenoids are found in food plants in free form or as fatty acid esters. Most studies have been carried out after saponification procedures, so the resulting data do not represent the native carotenoid composition of plant tissues. Therefore, nonsaponified extracts of 64 fruits and vegetables have been screened to determine the amount of carotenoid esters in food plants. Because one of the major problems in the quantitation of carotenoids is the availability of pure standard material, the total carotenoid ester content was calculated as lutein dimyristate equivalents. Lutein dimyristate was independently synthesized from lutein and myristoyl chloride. The highest ester concentrations were found in red chili (17.1 mg/100 g) and orange pepper (9.2 mg/100 g); most of the investigated fruits and vegetables showed concentrations up to 1.5 mg/100 g. Special attention was dedicated to beta-cryptoxanthin esters. To enable an accurate detection of the beta-cryptoxanthin ester content, beta-cryptoxanthin was purified from papaya and used for synthesis of beta-cryptoxanthin laurate, myristate, and palmitate, representing the major beta-cryptoxanthin esters in food plants. The study proved tropical and subtropical fruits to be an additional source of beta-cryptoxanthin esters in the human diet. The contents ranged from 8 microg/100 g beta-cryptoxanthin laurate in Tunisian orange to 892 microg/100 g beta-cryptoxanthin laurate in papaya.     

Influence of Soluble and Slow-Release Fertilizers on Vegetative Growth of Containerized Citrus Nursery Trees

The production system for certified citrus nursery trees in São Paulo State, Brazil, stipulates the use of screenhouses, rigorous selection of rootstocks, and the production of budwood under high standards in order to prevent diseases such as sudden death, Citrus Var, and foot rot (Phytophthora spp.). The establishment of adequate nutritional levels for citrus nursery trees also leads to higher production efficiency in this system. This work was divided into two trials. The first evaluated the influence of certain concentrations and formulas of slow-release fertilizer on the growth of ‘Pera’ sweet orange (Citrus sinensis L. Osbeck) budded on ‘Rangpur’ lime (Citrus limonia Osbeck) on two substrates. The development of ‘Rangpur’ lime liners was not influenced by composition of the substrate, nor by the concentrations or formulas of slow-release fertilizers. Substrate composition and formulas, or concentrations of fertilizers also did not affect budded tree growth, except that the greatest root fresh and dry matter were found in plants cultivated with lower concentrations. The second trial evaluated the influence of different soluble and slow-release fertilizers on growth of ‘Valencia’ sweet orange (Citrus sinensis L. Osbeck) nursery trees budded on ‘Rangpur’ lime. Scion length, stem diameter, scion fresh and dry matter, and leaf area were not affected by fertilizer sources. Fertigation induced the greatest development of roots (fresh and dry matter) when limestone was added.     

Application of tristimulus colorimetry to estimate the carotenoids content in ultrafrozen orange juices

Tristimulus Colorimetry was applied to characterize the color of Valencia late orange juices. Color measurements were made against white background and black background. The profile of the main carotenoids related to the color of the juices was determined by HPLC. Significant correlations (p < 0.05) between b*, Cab* and h(ab) and the content of beta-cryptoxanthin, lutein + zeaxanthin and beta-carotene were found. The correlations between the color parameters L*, a*, b*, Cab* and h(ab) and the carotenoids content were also explored by partial least squares. The results obtained have shown that it is possible to obtain equations, by means of multiple regression models, which allow the determination of the individual carotenoid levels from the CIELAB color parameters, with R2 values always over 0.9. In this sense, equations have been proposed to calculate the retinol equivalents (1 RE = 1 microgram retinol = 12 micrograms beta-carotene = 24 micrograms alpha-carotene = 24 micrograms beta-cryptoxanthin) of the orange juice analyzed as a function of the color parameters calculated from measurement made against white and black backgrounds. The average RE per liter of juice obtained by HPLC was 51.07 +/- 18.89, whereas employing these equations, average RE values obtained were 51.16 +/- 1.36 and 51.21 +/- 1.70 for white background and black background, respectively.     

Meta-analysis in the Selection of Groups in Varieties of Citrus

Brazil is the largest producer of oranges (Citrus sinensis) in the world. The nutrient management of tree orchards is designed from experiments with a limited number of varieties. This knowledge is transferred to other varieties by diagnosing tissue nutrient composition and tree demand. Compositional data analysis has been first applied to tissue analysis of agricultural crops using centered log ratios with compositional nutrient diagnosis (CND-clr). The isometric log ratio (ilr) transformation is a new approach based on binary nutrient ratios and the principle of orthogonality (CND-ilr). We analyzed eleven nutrients: nitrogen (N), sulfur (S), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), boron (B), copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) in leaf tissue samples across 108 commercial plots (thirty-one grow Valencia, twenty-two Hamlim, twenty Pera, and thirty-five Natal). Nutrients were partitioned between macro- and micronutrients as well as anionic and cationic species. The effect size of varieties over Valencia was quantified by the mean and standard deviation of ilr values across ilr coordinates. Specific varietal nutrient profiles and ilr norms were defined. The nutrient profile of orange varieties could be classified into homogeneous groups to take advantage of fertilizer trials conducted on varieties of the same group. The Aitchison distance and a perturbation vector could be instrumental for diagnostic purposes and nutrient management.     

The xanthophyll composition of biofortified maize (Zea mays Sp.) does not influence the bioefficacy of provitamin a carotenoids in Mongolian gerbils (Meriones unguiculatus)

Maize has been targeted for biofortification with provitamin A carotenoids through traditional breeding. Two studies were conducted in gerbils to evaluate factors that may affect provitamin A activity. Maize diets had equal theoretical concentrations of vitamin A (VA) assuming 100% bioefficacy. Study 1 ( n = 57) varied the ratio of beta-cryptoxanthin and beta-carotene but maintained the same theoretical VA. Study 2 ( n = 67) varied lutein and zeaxanthin. Other treatments were oil, VA, or beta-carotene doses. Serum and livers were analyzed for VA and carotenoids. In study 1, total liver VA did not differ among the maize groups. In study 2, total liver VA of the VA and maize groups were higher than controls ( P < 0.05). Conversion factors were 2.1-3.3 mug beta-carotene equivalents to 1 mug retinol. Twice the molar amount of beta-cryptoxanthin was as efficacious as beta-carotene and the proportion of beta-cryptoxanthin or xanthophylls did not appreciably change the VA value of biofortified maize.     

Differentiation of several geographical origins in single-strength Valencia orange juices using quantitative comparison of carotenoid profiles.

Pure Valencia orange (Citrus sinensis) juices (64 samples) from Spain, Israel, Belize, Cuba, and Florida, harvested during two seasons (1996-1997 and 1997-1998), were analyzed for their carotenoid profiles. The detection of saponified carotenoid pigments has been achieved and quantitated using a photodiode array detection monitored at 350, 430, and 486 nm. Carotenoid pigments commonly found in the orange variety Valencia have been separated on a polymeric C-30 column using a ternary gradient as eluent. Pure Valencia juices from oranges grown in Mediterranean regions (Israel and Spain) have a high carotenoid content, expressed in beta-carotene (5-18 and 14-35 mg L(-)(1), respectively), compared to those grown in tropical and subtropical regions (Cuba, Belize, and Florida) (4-10, 2-8, and 5-10 mg L(-)(1), respectively). Quantitative results allowed the differentiation of Valencia variety geographical origins, in particular, the Mediterranean area from tropical and subtropical areas, using multidimensional analyses of carotenoid contents.     

Carotenoids from new apricot (Prunus armeniaca L.) varieties and their relationship with flesh and skin color

Thirty-seven apricot varieties, including four new releases (Rojo Pasión, Murciana, Selene, and Dorada) obtained from different crosses between apricot varieties and three traditional Spanish cultivars (Currot, Mauricio, and Búlida), were separated according to flesh color into four groups. The L*, a*, b*, hue angle, and chroma color measurements on the skin and flesh as well as other quality indices including flesh firmness, soluble solids, titratable acidity, and pH were plotted against the total carotenoid content measured by HPLC. Among the 37 apricot varieties, the total carotenoid content ranged from 1,512 to 16,500 microg 100 g(-1) of edible portion, with beta-carotene as the main pigment followed by beta-cryptoxanthin and gamma-carotene. The wide range of variability in the provitamin A content in the apricot varieties encouraged these studies in order to select the breeding types with enhanced carotenoid levels as the varieties with a higher potential health benefit. The carotenoid content was correlated with the color measurements, and the hue angle in both flesh and peel was the parameter with the best correlation (R = 0.92 and 0.84, respectively). An estimation of the carotenoid content in apricots could be achieved by using a portable colorimeter, as a simple and easy method for field usage applications.