Semisynthesis of Betaxanthins from Purified Betacyanin of Opuntia dillenii sp.: Color Stability and Antiradical Capacity.

The availability of pure individual betalains in sufficient quantities which permit deeper understanding is still a challenge. This study investigates the high-yielding semisynthesis of betaxanthins using betalamic acid from a natural source (Opuntia dillenii), followed by condensation with ʟ-amino acids and further purification. Moreover, the color stability of the four synthesized individual betaxanthins, namely proline (ʟ-ProBX), alanine (ʟ-AlaBX), leucine (ʟ-LeuBX), and phenylalanine (ʟ-PheBX) betaxanthins, was investigated at different pHs. Their relative contribution to free radical scavenging was also scrutinized by TEAC and DPPH. ʟ-AlaBX and ʟ-LeuBx showed a significantly (p < 0.05) higher antioxidant activity, whereas ʟ-ProBX was the most resistant to the hydrolysis of betaxanthin and hence the least susceptible to color change. The color stability was strongly influenced by pH, with the color of ʟ-ProBX, ʟ-LeuBX, and ʟ-AlaBX at pH 6 being more stable, probably due to the easier hydrolysis under acid conditions. The semisynthesis and purification allowed us to have available remarkable quantities of pure individual betaxanthins of Opuntia dillenii for the first time, and to establish their color properties and antioxidant capacity. This study could be a step forward in the development of the best natural food colorant formulation, based on the betalain structure, which is of special interest in food technology.

Revalorization of Colombian purple corn Zea mays L. by-products using two-step column chromatography.

Colombian purple corn Zea mays L. by-products have been chemically characterized. To achieve this, after Amberlite XAD-7 purification and Sephadex LH-20 fractionation, the accurate anthocyanin and flavonol profile using UHPL-DAD-ESI-MS, total monomeric anthocyanin (TMA), polyphenols using Folin-Ciocalteau reduction capacity (FCRC), and antioxidant activity (DPPH and TEAC) of each fraction were performed. Cob and leaves illustrated a more complete flavonoid profile and a higher content of anthocyanins and flavonols, strongly related to the highest reducing power and radical scavenging activity compared to grains. Furthermore, the most antioxidant fractions corresponded to the higher molecular weight compounds. The cob and leaves were enriched in cyanidin-3-O-glucoside, cyanidin-3-O-malonyl-hexoside, and peonidin-3-O-glucoside, peonidin-3-O-(6''-malonyl-glucoside). The purification and fractionation allowed us to establish the chemical and antioxidant characterization, and the resulting revalorization, of purple corn by-products for the first time, and to have available pure fractions of Zea mays L. for a wide diversity of industries.

Identification of New Betalains in Separated Betacyanin and Betaxanthin Fractions from Ulluco (Ullucus tuberosus Caldas) by HPLC-DAD-ESI-MS.

An improved methodology of achieving an accurate separation of pure fractions of betacyanins and betaxanthins from Ullucus tuberosus Caldas has been carried out. For that purpose, an in-depth chemical identification of each betalain fraction using HPLC-DAD-ESI-MS was developed. This procedure allowed to evaluate the fractionation efficiency and also identify a large number of betalains, most of which have not been described so far in this raw material: betanidin- and isobetanidin-5-O-(4'-O-malonyl-ß-glucoside), 2-decarboxy-phyllocactin, betanidin- and isobetanidin-6-O-(6'-O-feruloyl)-ß-glucoside (gomphrenin and isogomphrenin III), dehydro-phyllocactin and isophyllocactin, and arginine and glycine-betaxanthins (portulacaxanthin III). Moreover, the availability of pure betalain fractions by the proposed methodology permitted to establish the total betalain content and the antioxidant activity of both separated betacyanin and betaxanthin fractions of ulluco for the first time. The results suggest Ullucus tuberosus as an underutilized food bioactive source with a high concentration of total betaxanthins (21.8 µg indicaxanthin/g fresh ulluco) and betacyanins (44.5 µg betanin/g fresh ulluco), strongly correlated to the Folin-Ciocalteau reduction capacity.

Analysis of Phenolic Composition of Byproducts (Seeds and Peels) of Avocado (Persea americana Mill.) Cultivated in Colombia.

The byproducts (seeds and peels) of an avocado cultivated in the south of Colombia were extracted with aqueous acetone and their antioxidant properties were measured with ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and DPPH (2,2-diphenyl-1-picrylhydrazyl) assays, and total polyphenol content was determined by Folin-Ciocalteu method. A bioguided fractionation was performed, first by SPE (solid phase extraction) on Amberlite XAD-7, and then by size exclusion chromatography on Sephadex LH-20. The polyphenolic-rich extracts and their fractions were analyzed by ultra-performance liquid chromatography-electrospray ionization-mass spectrometry (UPLC-ESI-MS/MS), finding the presence of organic acids, hydroxycinnamic acids, catechins, free and glycosylated flavonoids, and dimeric and trimeric procyanidins. Catechin, epicatechin, six quercetin derivatives, four dimeric procyanidins (three type B and one type A), and three trimeric procyanidins (two type B and one type A) were detected in the most active fractions of avocado peel and seeds. The most antioxidant fractions contain the higher molecular weight phenolic compounds (condensed tannins).

Impact of pH and temperature on the colour and betalain content of Colombian yellow pitaya peel (Selenicereus megalanthus).

The effects of different pHs (4, 5 and 6), temperatures (4, 20 and 80 °C) and storage (up to 12 days) on differential tristimulus colorimetry and betalain content related to the colour of yellow pitaya (Selenicereus megalanthus) have been investigated. The peel of the yellow pitaya was extracted with different solvents to see its colorant capacity. Highly-acidic extracts (pH 4) showed the lowest betalain content, chroma (C* ab = 60 against 70) and the yellow component of the colour (b*). Storage temperature manifested a great influence on CIELAB parameters when yellow pitaya peel was added to highly-acidic foodstuffs, with a tendency towards red hues (h ab , from 100° to 85°) and remarkable changes on lightness (L*, from 90 to 75) as temperature increased. However, low-acidic extracts (pH 5 and 6) were superior from a colour stability standpoint, not being influential the temperature of storage. All colour changes according to pH and temperature were visually appreciable by human eyes (∆E* ab  > 3). New opportunities for diversification of colorant market could be possible by employing yellow pitaya peel as natural resource.

Potential use of new Colombian sources of betalains. Color stability of ulluco (Ullucus tuberosus) extracts under different pH and thermal conditions.

The potential use of ulluco (Ullucus tuberosus) extracts to be added as natural colorant to other products has been studied. The stability of ulluco extracts at different pHs and temperatures over time has been thoroughly conducted. Our attention was focused on the tristimulus colorimetry, differential colorimetry and betalains related to color. On the basis of the results, although ulluco extract adjusted to pH4 showed a significantly lower color intensity (C*ab~40), the stability of red hue (hab) over time was higher. Betalain content showed the same trend, and lower values in highly-acidic extracts have been reported. It could be also affirmed that visually appreciable color changes (ΔE*ab>2) were induced when pH changed and different temperatures were applied. Despite of the vivid red color of the initial extracts, ulluco extracts added to low-acidic foodstuffs showed a tendency towards yellowish tonalities (values of hab from 45° to 80°), mitigated by using refrigeration storage conditions (hab values from 45° to 55°).

Lesões coronarianas de bifurcação: classificação, estratégias de tratamento e perspectivas: revisão / Coronary bifurcation lesions: classification, strategies of treatment and perspectives: review

A ocorrência de obstruções coronarianas que envolvem ramos laterais, com maior ou menor risco de oclusão, não é um evento raro. O tratamento percutâneo destas lesões de bifurcação tem sido um desafio para a cardiologia intervencionista. A apresentação extremamente variada, seja pela disposição dos ramos, propiciou a descrição de várias classificações. Ainda com a utilização de angioplastia coronária com cateter-balão, muitas técnicas foram escritas. Todas apresentavam resultados tardios poucos satisfatórios. Com o aparecimento dos stents na prática clínica, outras estratégias foram descritas, com a utilização de um e dois stents. No entanto, as taxas de revascularização da lesão-alvo permaneceram altas. O uso de stents com eluição...