Patricia Esquivel

Characterization of chromoplasts and carotenoids of red- and yellow-fleshed papaya (Carica papaya L.).

Chromoplast morphology and ultrastructure of red- and yellow-fleshed papaya (Carica papaya L.) were investigated by light and transmission electron microscopy. Carotenoid analyses by LC–MS revealed striking similarity of nutritionally relevant carotenoid profiles in both the red and yellow varieties. However, while yellow fruits contained only trace amounts of lycopene, the latter was found to be predominant in red papaya (51% of total carotenoids). Comparison of the pigment-loaded chromoplast ultrastructures disclosed tubular plastids to be abundant in yellow papaya, whereas larger crystalloid substructures characterized most frequent red papaya chromoplasts. Exclusively existent in red papaya, such crystalloid structures were associated with lycopene accumulation. Non-globular carotenoid deposition was derived from simple solubility calculations based on carotenoid and lipid contents of the differently colored fruit pulps. Since the physical state of carotenoid deposition may be decisive regarding their bioavailability, chromoplasts from lycopene-rich tomato fruit (Lycopersicon esculentum L.) were also assessed and compared to red papaya. Besides interesting analogies, various distinctions were ascertained resulting in the prediction of enhanced lycopene bioavailability from red papaya. In addition, the developmental pathway of red papaya chromoplasts was investigated during fruit ripening and carotenogenesis. In the early maturation stage of white-fleshed papaya, undifferentiated proplastids and globular plastids were predominant, corresponding to incipient carotenoid biosynthesis. Since intermediate plastids, e.g., amyloplasts or chloroplasts, were absent, chromoplasts are likely to emerge directly from proplastids.

Carotenoids are more bioavailable from papaya than from tomato and carrot in humans: a randomised cross-over study

Carrot, tomato and papaya represent important dietary sources of β-carotene and lycopene. The main objective of the present study was to compare the bioavailability of carotenoids from these food sources in healthy human subjects. A total of sixteen participants were recruited for a randomised cross-over study. Test meals containing raw carrots, tomatoes and papayas were adjusted to deliver an equal amount of β-carotene and lycopene. For the evaluation of bioavailability, TAG-rich lipoprotein (TRL) fractions containing newly absorbed carotenoids were analysed over 9·5 h after test meal consumption. The bioavailability of β-carotene from papayas was approximately three times higher than that from carrots and tomatoes, whereas differences in the bioavailability of β-carotene from carrots and tomatoes were insignificant. Retinyl esters appeared in the TRL fractions at a significantly higher concentration after the consumption of the papaya test meal. Similarly, lycopene was approximately 2·6 times more bioavailable from papayas than from tomatoes. Furthermore, the bioavailability of β-cryptoxanthin from papayas was shown to be 2·9 and 2·3 times higher than that of the other papaya carotenoids β-carotene and lycopene, respectively. The morphology of chromoplasts and the physical deposition form of carotenoids were hypothesised to play a major role in the differences observed in the bioavailability of carotenoids from the foods investigated. Particularly, the liquid-crystalline deposition of β-carotene and the storage of lycopene in very small crystalloids in papayas were found to be associated with their high bioavailability. In conclusion, papaya was shown to provide highly bioavailable β-carotene, β-cryptoxanthin and lycopene and may represent a readily available dietary source of provitamin A for reducing the incidence of vitamin A deficiencies in many subtropical and tropical developing countries.

Chemical and Morphological Characterization of Costa Rican Papaya (Carica papaya L.) Hybrids and Lines with Particular Focus on Their Genuine Carotenoid Profiles

Papaya (Carica papaya L.) F1 hybrids and inbred lines grown in Costa Rica were screened for morphological and nutritionally relevant fruit traits. The qualitative composition of carotenoids showed great similarity, being mostly composed of free and esterified β-cryptoxanthins accompanied by β-carotene, lycopene, and biosynthetic precursors. High levels of (all-E)-lycopene and its isomers were distinctive for red-fleshed hybrids, whereas yellow-fleshed fruits were virtually devoid of lycopenes. Because carotenoid levels among the investigated hybrids and lines differed significantly, this study supports the hypothesis of an exploitable genetic variability, and a potential heterotic effect regarding carotenoid expression may be instrumental in papaya-breeding programs. Due to significantly higher levels of provitamin A carotenoids and coinciding high levels of total lycopene, particularly red-fleshed hybrids might represent prospective sources of these compounds. Furthermore, the nutritional value of some genotypes was boosted by substantial amounts of ascorbic acid (up to 73 mg/100 g of fresh weight), which correlated to total soluble solids (R(2) = 0.86).

Phenolic Compound Profiles and their Corresponding Antioxidant Capacity of Purple Pitaya (Hylocereus sp.) Genotypes

Folin-Ciocalteu and TEAC (Trolox equivalent antioxidant capacity) assay together with the spectrophotometric determination of betalains were applied to investigate the correlation between phenolics and their contribution to the antioxidant capacity of five different Costa Rican genotypes of purple pitaya (Hylocereus sp.) and of H. polyrhizus fruits. Maximum antioxidant capacity, total phenolic and betalain contents were observed in the genotype ‘Lisa’. While non-betalainic phenolic compounds contributed only to a minor extent, betalains were responsible for the major antioxidant capacity of purple pitaya juices evaluated. The phenolic pattern of each genotype was also thoroughly investigated using liquid chromatography coupled to positive electrospray ionization (ESI) tandem mass spectrometry. In addition to the well known betalains previously reported in Hylocereus fruits, several biosynthetic precursors were detected. Notably, decarboxylated and dehydrogenated betalains were identified as genuine compounds of the juices. Some of these compounds were previously described as artifacts upon heat exposure. Moreover, gallic acid was identified for the first time in pitaya fruits. While the phenolic profiles generally differed between genotypes, phenolic compound composition of ‘Rosa’ resembled that of H. polyrhizus with respect to total contents of betacyanins, betalainic precursors, phyllocactin and cyclo-Dopa malonyl-glucosides.

Deposition Form and Bioaccessibility of Keto-carotenoids from Mamey Sapote (Pouteria sapota), Red Bell Pepper (Capsicum annuum), and Sockeye Salmon (Oncorhynchus nerka) Filet

The ultrastructure and carotenoid-bearing structures of mamey sapote (Pouteria sapota) chromoplasts were elucidated using light and transmission electron microscopy and compared to carotenoid deposition forms in red bell pepper (Capsicum annuum) and sockeye salmon (Oncorhynchus nerka). Globular-tubular chromoplasts of sapote contained numerous lipid globules and tubules embodying unique provitamin A keto-carotenoids in a lipid-dissolved and presumably liquid-crystalline form, respectively. Bioaccessibility of sapotexanthin and cryptocapsin was compared to that of structurally related keto-carotenoids from red bell pepper and salmon. Capsanthin from bell pepper was the most bioaccessible pigment, followed by sapotexanthin and cryptocapsin esters from mamey sapote. In contrast, astaxanthin from salmon was the least bioaccessible keto-carotenoid. Thermal treatment and fat addition consistently enhanced bioaccessibility, except for astaxanthin from naturally lipid-rich salmon, which remained unaffected. Although the provitamin A keto-carotenoids from sapote were highly bioaccessible, their qualitative and quantitative in vivo bioavailability and their conversion to vitamin A remains to be confirmed.

Carotenoids and carotenoid esters of orange- and yellow-fleshed mamey sapote (Pouteria sapota (Jacq.) H.E. Moore & Stearn) fruit and their post-prandial absorption in humans

Although different genotypes of mamey sapote with distinct pulp colors are consumed in countries from Central to South America, in-depth knowledge on genotype-related differences of their carotenoid profile is lacking. Since the fruit was found to contain the potentially vitamin A-active keto-carotenoids sapotexanthin and cryptocapsin, we sought to qualitatively and quantitatively describe the carotenoid profile of different genotypes by HPLC-DAD-MSn. Sapotexanthin and cryptocapsin were present in all genotypes. Keto-carotenoids such as cryptocapsin, capsoneoxanthin, and their esters were most abundant in orange-fleshed fruit, whereas several carotenoid epoxides prevailed in yellow-fleshed fruit. Differing carotenoid profiles were associated with different color hues of the fruit pulp, while the widely variable carotenoid content (3.7-8.0mg/100gFW) was mainly reflected by differences in color intensity (chroma C∗). Furthermore, the post-prandial absorption of sapotexanthin to human plasma was proven for the first time. Besides sapotexanthin, cryptocapsin was found to be resorbed.

Carotenoids, carotenoid esters, and anthocyanins of yellow-, orange-, and red-peeled cashew apples (Anacardium occidentale L.)

Pigment profiles of yellow-, orange-, and red-peeled cashew (Anacardium occidentale L.) apples were investigated. Among 15 identified carotenoids and carotenoid esters, β-carotene, and β-cryptoxanthin palmitate were the most abundant in peels and pulp of all samples. Total carotenoid concentrations in the pulp of yellow- and red-peeled cashew apples were low (0.69-0.73 mg/100g FW) compared to that of orange-peeled samples (2.2mg/100g FW). The color difference between the equally carotenoid-rich yellow and red colored samples indicated the presence of a further non-carotenoid pigment type in red peels. Among four detected anthocyanins, the major anthocyanin was unambiguously identified as 7-O-methylcyanidin 3-O-β-D-galactopyranoside by NMR spectroscopy. Red and yellow peel color was chiefly determined by the presence and absence of anthocyanins, respectively, while the orange appearance of the peel was mainly caused by increased carotenoid concentrations. Thus, orange-peeled fruits represent a rich source of provitamin A (ca. 124 μg retinol-activity-equivalents/100g pulp, FW).

Chemical characterization of Central American pitaya ( Hylocereus sp.) seeds and seed oil

Central American red pitaya (Hylocereussp.) seeds were studied for their chemical and nutritional traits with particular reference to the fatty acid (FA) profile of the seed oil. Proximate seed composition averaged 352 g/kg, 302 g/kg, 296 g/kg, 206 g/kg, 126 g/kg, and 21 g/kg for total carbohydrates, dietary fiber, fat, protein, moisture, and ash, respectively. FA composition of pitaya seed oil determined by GC–MS and quantified by GC-FID was dominated by unsaturated FAs (753 g/kg). Interestingly, linoleic acid was found to be the only polyunsaturated and most abundant FA (466 g/kg), whereas palmitoleic (3 g/kg), oleic (239 g/kg), and cis-11-vaccenic acid (45 g/kg) were the major monounsaturated FAs. Palmitic (182 g/kg), stearic (49 g/kg), and arachidic acid (18g/kg) represented the saturated FA fraction. Iodine absorption value, saponification number and free fatty acid value amounted to 105.6 g I2/100 g, 235.7 mg KOH/g, and 1.9 mg KOH/g, respectively.

Carotenoids and xanthophyll esters of yellow and red nance fruits (Byrsonima crassifolia (L.) Kunth) from Costa Rica

Carotenoid profiles, by means of HPLC-PDA-MSn, and CIE-L*C*h° colour values of yellow and red nance fruits from Costa Rica were elucidated. Among 16 carotenoids detected, (all-E)-lutein was the most abundant accounting for >80% of the total carotenoids, followed by (all-E)-zeaxanthin (9-11%) and (all-E)-β-carotene (2-9%). Minor constituents were (Z)-isomers of lutein and β-carotene, as well as diverse lutein diesters. Among the esters, lutein dimyristate was the most abundant as substantiated by the comparison with a marigold flower extract. Total carotenoids in the peel (616.2 μg/100 g of FW in yellow nance and 174.2 μg/100 g of FW in red nance) were higher than in the pulp (39.4 μg/100 g of FW in yellow nance and 31.4 μg/100 g of FW in red nance). Since carotenoid profiles of yellow and red varieties were qualitatively similar, although the colour values showed significant differences (77.2 and 88.6 h° in peel and pulp of yellow nance, versus 32.7 and 67.3 h° in peel and pulp of red nance, respectively), pigments other than carotenoids may impart the colour of red nance. High lutein content renders nance fruit as a nutritionally relevant source of this micronutrient.

Potential Opportunities and Challenges for Research Collaboration with Latin America in Agriculture and Food Science

UCR::Vicerrectoria de Docencia::Ciencias Agroalimentarias::Facultad de Ciencias Agroalimentarias::Escuela de Tecnologia de Alimentos