Synthesis of Pyrodextrins and Enzymatically Resistant Maltodextrins from Makal (Xanthosoma yucatenensis) Starch.

Research background: Enzymatically resistant maltodextrins (ERM) are a resistant starch type 4, synthesized from native starch. They are obtained by the sequential application of two processes: pyrodextrinization, which produces pyrodextrins, and enzymatic hydrolysis, which produces ERM. In these processes atypical bonds are formed that confer pyrodextrins and ERM similar properties to dietary fiber, such as resistance to digestion. The aim of this work is to determine and evaluate some physicochemical properties of pyrodextrins and ERM obtained from native starch isolated from makal (Xanthosoma yucatanense) tubers. Experimental approach: Pyrodextrinization and complementary hydrolysis were conducted using factorial designs. For pyrodextrinization, factors and their levels were (m(starch):V(HCl))=80:1 and 160:1 (c(HCl)=2.2 M), temperature 90 and 110 °C and reaction time 1 and 3 h, and for CH, α-amylase per pyrodextrin volume fractions 0.5 and 1 µL/mL and reaction time 10 and 30 min. The physicochemical profile included determination of resistant starch content, estimation of color change (ΔE), microscopy and determination of dextrose equivalents (DE). Results and conclusions: According to the factorial design, the best treatment conditions for pyrodextrinization were: (m(starch):V(HCl))=160:1, 90 °C and 3 h, since they resulted in the highest resistant starch content (84.73 %) and the lowest ΔE (3.742). Due to the low DE (13.89 %), increased amount of resistant starch (90.73 %) and low ΔE (4.24) in the resulting ERM, complementary hydrolysis with α-amylase per pyrodextrin volume fraction 0.5 µL/mL and hydrolysis time 10 min was selected as the best treatment. Novelty and scientific contribution: The results show that the pyrodextrins and ERM obtained from makal can be used as ingredients for the development of functional foods, due to their high content of indigestible material and low degree of browning.

Lead tolerance of Laguncularia racemosa is associated to high proline accumulation and high antioxidant capacities.

Mangrove forests are threatened by the continuous discharge of inorganic pollutants and studies show that coasts receive high levels of heavy metals, from which lead (Pb) is one of the most persistent and toxic. In the present study, lead accumulation capacity, as well as its toxicological effects and tolerance mechanisms, such as proline accumulation and increased antioxidant capacity were evaluated in two contrasting mangrove species: Avicennia germinans and Laguncularia racemosa. Six-month-old plants were exposed to different concentrations of lead nitrate (0, 75, 150, and 300 µM) and samples of roots and leaves were taken from all treatments at different times during a 30d exposure period. Both species accumulated Pb in their tissues mainly in the roots, but L. racemosa had a greater capacity to accumulate Pb than A. germinans. Nevertheless, lead exposure caused less leaf chlorosis, lower reduction in the efficiency of photosystem II, lower reduction of daily photosynthetic rates, and lower electrolyte leakage in L. racemosa than in A. germinans. In line with those results, L. racemosa, in response to Pb exposure, accumulated more proline and showed higher antioxidant capacity than A. germinans, in both roots and leaves. Altogether, L. racemosa might be more suitable for restoration purposes, as it is not only capable of accumulating more Pb in its tissues but also shows greater tolerance to the stress caused by lead.

Effect of extraction method and specie on the content of bioactive compounds and antioxidant activity of pumpkin oil from Yucatan, Mexico.

In this study, the effect of the extraction method (mechanical pressing, MP and organic solvent, OS) and the specie (Cucurbita argyrosperma Huber, CA; and Cucurbita moschata Duchesne, CM) on the content of bioactive compounds and antioxidant activity of oil from pumpkin of Yucatan, Mexico was investigated. Between the two extraction methods, the oil extracted by MP obtained the highest values for total phenolic compounds (TPC), total carotenoids, squalene, quercetin, ß-carotene, fucosterol, stigmasterol and antioxidant activity (DPPH, ABTS and reducing power). Between the two species, the CM oil extracted with MP or OS exhibited the highest values for carotenoids, sterols and antioxidant activity (DPPH and ABTS). Thus, it can be concluded that the method and specie affect the composition of bioactive compounds and antioxidant activity of the pumpkin oil. This information is useful for the extraction of pumpkin oil with a higher content of compounds, of interest for the industry.

Phytochemical Profile, Toxicity, and Pharmacological Potential of Peels from Four Species of Tropical Fruits.

Tropical fruit peels are generally discarded as waste, yet they contain bioactive substances that could have various uses; in addition, their pharmacological potential remains unexplored. This study aims to characterize the phytochemical profile, toxicity, and pharmacological potential of methanol extracts obtained from the peels of the following tropical fruit species: Annona squamosa L. (purple sugar apple), Annona reticulata L. (custard apple), Chrysophyllum cainito L. (green star apple), and Melicoccus bijugatus Jacq. (mamoncillo). Methanol peel extracts were obtained by maceration. All extracts contained flavonoids, anthraquinones, and triterpenoids as determined by colorimetric methods. A. squamosa and C. cainito exhibited the highest content of total phenols as assayed by the Folin-Ciocalteu method. M. bijugatus showed the highest content of total sugars (fructose, glucose, and sucrose) as determined by high-performance liquid chromatography. A. squamosa and C. cainito presented the highest antioxidant capacities (according to 2,2'-diphenyl-1-picrylhydrazyl, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid, and cupric reducing antioxidant capacity assays), displayed moderate toxicity against HCT-116 cells, and increased the vinblastine susceptibility of MCF-7/Vin+. A. squamosa and M. bijugatus extracts demonstrated modulation of acetylcholinesterase activity, whereas those of A. reticulata showed anti-inflammatory activity by inhibiting protein denaturation. These results confirm that tropical fruit peels can be valuable sources of bioactive compounds, and our findings provide new information about their pharmacologic potential so that they can be used as raw material for the development of new drugs aimed at treating a variety of ailments.

Effects of polyphenol removal methods on the in vitro exsheathment inhibitory activity of Lysiloma latisiliquum extracts against Haemonchus contortus larvae.

It has been suggested that the anthelmintic (AH) activity of tannin-rich forages is related to their tannin content. However, reports on tropical fodders such as Lysiloma latisiliquum describe the same AH activity after the addition of tannin-blocking agents, suggesting that the activity either depends on the method of tannin blocking/removal or is due to other type of secondary metabolites. This study compared both the effect of the drying process of the plant material and the effect of different polyphenol removal methods on the AH activity of L. latisiliquum acetone-water extracts when tested against Haemonchus contortus. The results showed that the extraction of oven-dried (OD) leaves of L. latisiliquum yielded a CT-free extract with high AH activity. However, polyphenol-free fractions showed similar or lower AH activity levels as of those original OD extract. HPLC analysis confirmed that common polyphenolic metabolites are not responsible for the AH activity of L. latisiliquum.

Nitrate promotes capsaicin accumulation in Capsicum chinense immobilized placentas.

In chili pepper's pods, placental tissue is responsible for the synthesis of capsaicinoids (CAPs), the compounds behind their typical hot flavor or pungency, which are synthesized from phenylalanine and branched amino acids. Placental tissue sections from Habanero peppers (Capsicum chinense Jacq.) were immobilized in a calcium alginate matrix and cultured in vitro, either continuously for 28 days or during two 14-day subculture periods. Immobilized placental tissue remained viable and metabolically active for up to 21 days, indicating its ability to interact with media components. CAPs contents abruptly decreased during the first 7 days in culture, probably due to structural damage to the placenta as revealed by scanning electron microcopy. CAPs levels remained low throughout the entire culture period, even though a slight recovery was noted in subcultured placentas. However, doubling the medium's nitrate content (from 40 to 80 mM) resulted in an important increment, reaching values similar to those of intact pod's placentas. These data suggest that isolated pepper placentas cultured in vitro remain metabolically active and are capable of metabolizing inorganic nitrogen sources, first into amino acids and, then, channeling them to CAP synthesis.

Antioxidant compounds, antioxidant activity and phenolic content in peel from three tropical fruits from Yucatan, Mexico.

The aim of this study was to determine the antioxidant compounds, antioxidant activity and content of individual phenolic compounds of freeze-dried peel from three tropical fruits grown in Yucatan, México: purple star apple (Chrysophyllum cainito L.), yellow cashew and red cashew (Anacardium occidentale). The freeze-dried peels were good source of antioxidant compounds. ABTS and DPPH values in the peel from each fruit were 3050.95-3322.31 µM Trolox/100g dry weight (DW) or 890.19-970.01 mg of vitamin C/100 g DW, and 1579.04-1680.90 µM Trolox/100 g DW or 340.18-362.18 mg of vitamin C/100 g DW, respectively. Six phenolic compounds were identified in the peel from the tropical fruits studied: ferulic, caffeic, sinapic, gallic, ellagic and myricetin. This study demonstrated that freeze-dried peels from purple star apple, yellow cashew and red cashew, could serve as potential sources of antioxidants for use in food and pharmaceutical industries.

Determination of some physicochemical characteristics, bioactive compounds and antioxidant activity of tropical fruits from Yucatan, Mexico.

The aim to the study was to determine the physicochemical composition, bioactive compounds and antioxidant activity of fruits from Yucatan, Mexico such as star apple, cashew, mombin, mamey sapote, white sapote, sugar apple, sapodilla, dragon fruit, nance, ilama, custard apple, mamoncillo and black sapote. The physicochemical characteristics were different between fruits and were good sources of bioactive compounds. The edible part with the highest values of antioxidant activity were mamoncillo, star apple, mombin, cashew, white sapote, ilama, custard apple, sugar apple, and nance. Total soluble phenols content showed a correlation with antioxidant activity by ABTS (R=0.52, P⩽0.05) and DPPH (R=0.43, P⩽0.05). A high correlation was obtained between the two assays (ABTS and DPPH) used to measure antioxidant activity in the tropical fruit species under study (R=0.82, P⩽0.05). The results show promising perspectives for the exploitation and use of tropical fruits studied with significant levels of nutrients and antioxidant activity.

Postharvest ripening and maturity indices for maradol papaya / Maduración postcosecha e índices de madurez de papaya maradol / Amadurecimento Pos Colheita E Índices De Maturação De Papaya Maradol

Fruit ripening in papaya Carica papaya cultivars varies widely in terms of skin color changes, pulp firmness and shelf life. Most papaya ripening studies have been done using ‘Solo’ varieties. No objective maturity indices have been developed for Maradol papaya, and studies describing color changes during fruit ripening only cover the initial and final maturity stages. Changes in the main quality attributes of Maradol papaya were documented during the ripening process to identify maturity stages and define objective maturity indices to be applied as harvest indices and quality standards. Six maturity stages were identified and quality attribute value ranges proposed as quality standards. Skin color can be considered an appropriate maturity index, b* values are good indicators for early maturity stages, while a* value are better for late stages.

Las variedades de papaya muestran una amplia variación en la maduración del fruto en términos de ablandamiento, cambios del color de la cáscara y vida de anaquel. La mayoría de los estudios sobre maduración de papaya se han reportado en variedades ‘Solo’. No se han desarrollado índices de maduración objetivos para la variedad Maradol, los estudios que describen el cambio de color en la maduración del fruto cubren sólo a los estados de maduración inicial y final. Se evaluaron los cambios en los principales atributos de calidad de papaya Maradol durante la maduración para identificar estados de maduración y definir índices de maduración objetivos que puedan ser sugeridos como índices de cosecha y estándares de calidad. El color de la cáscara puede ser considerado como un índice de madurez apropiado, los valores de b* son buenos indicadores para los estados tempranos de madurez, mientras que los valores de a* son mejores para los últimos estados.

As variedades de papaya mostram uma ampla variação no amadurecimento do fruto em termos de amolecimento, mudança da cor da casca e vida nas gôndolas. A maioria dos estudos sobre amadurecimento de papaya tem sido relatado na variedade ‘Solo’. Não tem se desenvolvido índices de amadurecimento objetivos para a variedade Maradol, os estudos que descrevem a mudança de cor no amadurecimento do fruto abrangem somente aos estados de amadurecimento inicial e final. Avaliaram-se as mudanças nos principais atributos de qualidade de papaya Maradol durante o amadurecimento para identificar estados de amadurecimento e definir índices de amadurecimento objetivos que possam ser sugeridos como índices de colheita e estándares de qualidade. A cor da casca pode ser considerada como um índice de maturação apropriado, os valores de b* são bons indicadores para os estágios recentes de maturação, enquanto que os valores de a* são melhores para os últimos estágios.