Phenolic Compounds in Maize Grains and Its Nixtamalized Products

Among the cereals most consumed by humans, maize grain is in the third position, surpassed only by rice and wheat. In several countries, maize grain is the main source of carbohydrates and proteins. Maize grain is ranked as one of the cereals with the highest content of phenolic compounds. The importance for human health of the consumption of phenolic compounds is due to their proved antioxidant activity. Diets with high amount of antioxidants have been associated with a reduced probability of suffering degenerative chronic diseases. In maize grain, the phenolic acids predominate, among which the main is ferulic acid, followed by p‐coumaric acid, which are highly abundant in their bound forms. However, other phenolics such as anthocyanins, flavonols, and flavanols have been identified in colored maize grains. Additionally, the processing of maize grain into different products for human consumption incorporates changes both in quantity and quality of some phenolic compounds. In the present chapter, we present the most recent information available regarding phenolic compounds in maize grain and their nixtamalized products

Spatial-Temporal Evolution of Scientific Production about Genetically Modified Maize

Maize is the grain cereal that is the basis of human and animal diets in Mexico and Latin America; it constitutes an essential crop for global food security. The objective of this study was to analyze the spatial–temporal evolution of scientific production on the theme of GMO maize, through a bibliometric analysis of the texts available in the main editorial houses (Elsevier, Scopus, and Springer), open access journal articles database (Conricyt, Scielo, Redalyc, Latindex, Claryvate Analytics, Periodica, and DOAJ), and freely accessible web search engine Google Scholar, to determine the factors that influence the impact of the studies. From 1991 to 2019, 917 texts were found whose spatial–temporal evolution showed a linear growth that concentrated in Latin America (58.56%). The low impact (measured by the number of bibliographic citations) of scientific studies developed in countries of Latin America was related to their publication in journals edited in their own countries and in Spanish, which restricts the constructive criticism of peer review. For the case of Mexico, a spatial discrepancy was also found between research centers and production areas, which limits the transference of technology; and no specialized author in theme of GMO maize was found; the researchers responded to “scientific trends” in agreement with the agrarian policies of the timeS

Betalains and phenolic compounds profiling and antioxidant capacity of pitaya (Stenocereus spp.) fruit from two species (S. Pruinosus and S. stellatus)

[EN] Pitaya fruits (Stenocereus spp.) contain betalains and phenolic compounds that have not been completely characterized. Fruits of two ecotypes of S. pruinosus, red-fleshed (SpR) and orange-fleshed (SpO), and two of S. stellatus, red-fleshed (SsR) and white-fleshed (SsW), were characterized in their betalains and phenolic compounds. The chromatographic profile of betalains was similar in SpR, SpO, and SsR, where indicaxanthin, gomphrenin I, phyllocacthin, and their isomers predominated. Betaxanthins content was higher than betacyanins and ranged from 17,706.7 ± 1128.1 to 22,053.6 ± 328.1 mg/g dry sample. The identified phenolics mostly corresponded to hydroxycinnamoyl derivatives, flavonols and flavanones. The phenolics content was higher in S. stellatus than in S. pruinosus. The ecotype SsW, that had flesh without color, showed the highest concentration. The antioxidant capacity varied within 9.21 ± 0.84 and 2.41 ± 0.36 lmol Trolox/g fresh sample, as determined by the ABTS assay. By its phytochemical composition, the fruits of pitaya can be a good source of antioxidant compounds

Spatial Delimitation of Genetic Diversity of Native Maize and Its Relationship with Ethnic Groups in Mexico

Mexico, as a center of origin of maize, presents a high diversity of maize races. With the objective of spatially demarcating regions with high concentration of intraspecific diversity in Mexico, as a fundamental measure for the in situ conservation of their agrobiodiversity, Geographic Information Systems (GIS) tools have been used to generate diversity and richness indexes for 64 maize races cultivated in Mexico, using indexes to demarcate relationships to environmental factors such as temperature, precipitation, and altitude; the presence of indigenous groups; and the type of maize used. These relations allowed defining seven environmental units spatially, with characteristic maize races in each of them, which constitute priority areas for in situ conservation. In addition, a close relationship was found between the diversity of maize races and of ethnic groups, from the center to the south of the country, associated with the differences in maize use in different ethnic groups. This geographical demarcation of races and uses of maize will favor food security through specific measures of in situ conservation, as well as an increase in added value of maize by-products based on specific maize races conserved by local ethnic groupsS

Actividad antifúngica de accesiones de maíz (Zea mays L.) de grano con presencia de fenoles coloridos

El grano de maíz contiene elevadas cantidades de compuestos fenólicos los cuales poseen diversas actividades biológicas, entre las que se encuentra la actividad antifúngica (AAF). El objetivo del estudio fue determinar la AAF del extracto acetónico del grano de maíz de accesiones con diferentes coloraciones de grano. En el estudio Se emplearon 60 accesiones de grano azul morado (AZM), 34 accesiones de grano rojo cereza (RC) y 26 accesiones de grano rojo ladrillo (RL).  Se utilizaron las técnicas de microdilución en placa y la prueba de porcentaje de inhibición fúngica para evaluar la AAF de los granos de maíz.  Como agente patogénico se empleó una cepa de Fusarium oxysporum y el antifúngico comercial Itraconazol como testigo negativo. La prueba de microdilución en placa funcionó como filtro para los extractos de las accesiones, al reducir en 50 % las muestras que se sometieron a la prueba de porcentaje de inhibición, considerada cuantitativa de la AAF. Los extractos de las accesiones de grano AZM presentaron menor AAF que los de los granos RC y RL. Con la prueba de porcentaje de inhibición se comprobó la mayor AAF de los extractos de maíz con grano RC.  Ninguno de los extractos superó la AAF del antifúngico comercial Itraconazol. La AAF del grano de maíz está asociada con su color. DOI: https://doi.org/10.54167/tch.v17i2.117

Componentes de varianza de caracteres de maíz asociados al nixtamal

Los componentes de varianza y la heredabilidad de características de grano blanco, relacionadas con la calidad industrial de la harina nixtamalizada, fueron estimadas en cinco híbridos de maíz (Zea mayz L.) del tipo "media altura". El objetivo del trabajo fue conocer los componentes de varianza, la heredabilidad y la correlación de características de grano blanco asociadas con la calidad industrial del nixtamal de híbridos de maíz. Durante el ciclo Verano 2003, se estableció el experimento bajo condiciones de riego en tres localidades representativas de la región El Bajío. Se evaluaron nueve características físicas de grano y siete asociadas al proceso de "nixtamalización". Se identificaron cinco rasgos de interés para la industria del nixtamal: Peso o masa hectolítrica (densidad de grano) y peso de 100 granos, asociados al rendimiento de grano a tortilla; endospermo tipos harinoso y córneo, relacionados con la calidad de la tortilla; pericarpio retenido, asociado al rendimiento de grano a tortilla. La variable pericarpio retenido mostró una heredabilidad alta (h2 > 0.50), mientras que los caracteres peso hectolítrico, peso de cien granos, endospermo harinoso y endospermo córneo presentaron baja heredabilidad (h2 < 0.50). De acuerdo a los resultados observados en esta investigación, se recomienda seleccionar grano de maíz con valores de endospermo (porcentaje base seca del grano) de tipo harinoso menor de 36.4 %, tipo duro o córneo mayor de 46.4 %; además, el pericarpio retenido debería ser mayor de 35.8 %. Abstract Components of variance and heritability of white grain characteristics, related to industrial quality of nixtamalized corn flour, were estimated in five maize hybrids (Zea mayz L.) type "media altura". The objective of this study was to know components of variance, heritability and correlation coeficients among grain traits associated to nixtamal quality of white grain maize hybrid. During the Summer-2003 season, an experiment was established under irrigation conditions in three locations representative of the agriculture region "El Bajío". Nine physical characteristics of grain and seven more traits associated to corn "nixtamalización" industrial process were evaluated. Five important characteristics for "nixtamal" industry were identified: Hectoliter weight (grain density) and weight of 100 grains, associated to yield of grain to tortilla; endosperm corn types flour and hard, related to tortilla quality; retained pericarp, associated to yield of grain to tortilla. The variable retained pericarp showed a high heritability (h2 > 0.50), while for the characteristics: Hectoliter weight, weight of 100 grains, endosperm types flour and hard were the estimated heritability values were lower than 0.50. According to the observed results, it is recommendable to select endosperm corn values (percentage based on grain dry weight) type flour below 36.4 %, type hard greater than 46.4 %; moreover, the retained pericarp should be above 35.8 %. Keywords: Components of variance, heritability, genetic variation coefficient, nixtamal quality, retained pericar

Distribución potencial del híbrido Pleopeltis polylepis (Roemer ex Kunze) T. Moore var. polylepis x Polypodium guttatum Maxon (Polypodiaceae Pteridophyta): Áreas probables de simpatría

A través de los sistemas de información geográfica se pueden analizar variables biológicas y ambientales para generar modelos predictivos de distribución geográfica, útiles en la actualidad en estudios de biogeografía, genética, biología de la conservación y evolución de las especies. Farfán-Roldánet al. (2006) describieron un nuevo híbrido entrePleopeltis polylepisvar.polylepisyPolypodium guttatumcolectado en el Parque Nacional El Chico, en el estado de Hidalgo, y de este trabajo surgió el interés de estudiar la distribución de los progenitores de esta planta para obtener áreas de simpatría. Con este motivo se realizaron dos tipos de acercamiento: primero un análisis de la distribución geográfica de los progenitores, apoyados en ejemplares de diversos herbarios que fueron debidamente georeferenciados y se ubicaron en un mapa de la República Mexicana con un grid de medio grado, en segundo término se determinaron las áreas de distribución potencial con un análisis de variables bioclimáticas por medio del programa DIVA-GIS. Fue así que con base en los resultados obtenidos se proponen cinco áreas potenciales de distribución donde puede encontrarse el híbrido: la primera en Nuevo León, Tamaulipas y Coahuila, la segunda en el estado de Guanajuato, Jalisco y Zacatecas; la tercera en los estados de Querétaro, San Luís Potosí y parte de Guanajuato; otra en Hidalgo, Estado de México, Michoacán y el Distrito Federal, y una última comprende un área en los estados de Hidalgo, Puebla y Tlaxcala. El hecho de compartir los mismos hábitats y la proximidad filogenética de estos taxa son factores que pueden influir en la formación de los híbridos

The evolution of the ventilatory ratio is a prognostic factor in mechanically ventilated COVID-19 ARDS patients

Background: Mortality due to COVID-19 is high, especially in patients requiring mechanical ventilation. The purpose of the study is to investigate associations between mortality and variables measured during the first three days of mechanical ventilation in patients with COVID-19 intubated at ICU admission. Methods: Multicenter, observational, cohort study includes consecutive patients with COVID-19 admitted to 44 Spanish ICUs between February 25 and July 31, 2020, who required intubation at ICU admission and mechanical ventilation for more than three days. We collected demographic and clinical data prior to admission; information about clinical evolution at days 1 and 3 of mechanical ventilation; and outcomes. Results: Of the 2,095 patients with COVID-19 admitted to the ICU, 1,118 (53.3%) were intubated at day 1 and remained under mechanical ventilation at day three. From days 1 to 3, PaO2/FiO2 increased from 115.6 [80.0-171.2] to 180.0 [135.4-227.9] mmHg and the ventilatory ratio from 1.73 [1.33-2.25] to 1.96 [1.61-2.40]. In-hospital mortality was 38.7%. A higher increase between ICU admission and day 3 in the ventilatory ratio (OR 1.04 [CI 1.01-1.07], p = 0.030) and creatinine levels (OR 1.05 [CI 1.01-1.09], p = 0.005) and a lower increase in platelet counts (OR 0.96 [CI 0.93-1.00], p = 0.037) were independently associated with a higher risk of death. No association between mortality and the PaO2/FiO2 variation was observed (OR 0.99 [CI 0.95 to 1.02], p = 0.47). Conclusions: Higher ventilatory ratio and its increase at day 3 is associated with mortality in patients with COVID-19 receiving mechanical ventilation at ICU admission. No association was found in the PaO2/FiO2 variation

ZONAS DE SOBREPOSICION EN LAS AREAS DE DISTRIBUCION GEOGRAFICA DE LAS ESPECIES MEXICANAS DE DENDROCTONUS ERICHSON (COLEOPTERA: SCOLYTIDAE) Y SUS IMPLICACIONES ECOLOGICO-EVOLUTIVAS

Species of Dendroctonus are parasites of conifer forests (Pinaceae-Coniferales), their distribution range being associated with these forest communities. Natural co-existence of Dendroctonus species with ecological, morphological, and reproductiva differences is common; however, observations made in natural conditions suggest the co-existence, in time and space, of some species with similar biological features. The purpose of the present work was tó determine overlapping zones in the distribution range of Dendroctonus species in México. Our study was based on records of specimenes depositad in the main national entomological collections. Maps of distribution range of the species were made per State, which were the basis to determine overlapping zones by the propinquity method. The results show the presence of 27 overlapping zones of two to five species, where latitude, altitude, and host are similar. The presence of these zones suggests that co-existence of Dendroctonus species with similar biological attributes is common, and should be considered in the control of these insects. Additionally, ecological and evolutionary several aspects could be studied in these areas.Las especies del género Dendroctonus son parásitos específicos de bosques de coníferas (Pinaceae- Coniferales), de tal forma que su distribución geográfica está asociada con estas comunidades boscosas. La coexistencia natural entre las especies de Dendroctonus normalmente ocurre entre aquellas que presentan diferencias ecológicas, morfológicas y reproductivas evidentes; sin embargo, algunas observaciones realizadas en condiciones naturales, sugieren la coexistencia en espacio y tiempo entre algunas especies con atributos biológicos semejantes. El objetivo del presente trabajo fue determinar las zonas de sobreposición de las especies de Dendroctonus en México, por medio de registros de colecta obtenidos de las principales colecciones entomológicas del país. Se elaboraron mapas de distribución geográfica por estado, y a partir de ellos se delimitaron las áreas de sobreposición por el método de la propincuidad media. Los resultados muestran la presencia de 27 áreas de sobreposición de dos a cinco especies, las que coinciden en latitud, longitud, altitud y huésped. La presencia de estas zonas sugiere que la posible coexistencia de especies de Dendroctonus con atributos biológicos semejantes puede ser común y que debería considerarse en los programas de control de estos insectos. Además, plantea la posibilidad de estudiar diversos fenómenos ecológico- evolutivos que pueden presentarse en éstas especies en estos sitios