Technological properties of maize tortillas produced by microwave nixtamalization with variable alkalinity

This research was conducted to determine the quality, physicochemical, textural, compositional, nutritional, viscoamylographic and sensory properties of maize tortillas produced with a Modified tortilla-making process (MTMP) of variable alkalinity (0.125, 0.25 and 0.5% Ca(OH)2 w/w) and compared to the commercial brand MASECA ®. In general, tortillas from MTMP showed higher pH, total color difference (ΔE), tensile strength/cutting force, protein, lipids, crude fibre, lysine, tryptophan, in vitro protein digestibility and lower Hunter L value, loss of weight during cooking and moisture content than MASECA® tortillas. No significant differences were found in the sensory analysis of 22 descriptors of tortillas made from MASECA® and MTMP with Ca(OH)2 concentrations of 0.125 and 0.25% (w/w). However, panelist identified principal effects on changes in four attributes (aroma, appearance, flavor, and after taste flavor) and seven descriptors in tortillas from MTMP prepared with the maximum lime concentration (0.5% w/w). Microwave nixtamalization produce tortillas with acceptable physicochemical, textural, quality, compositional/nutritional and pasting properties.Key words: Maize, modified nixtamalization, tortillas, technological properties

Land cover and climate change may limit invasiveness of Rhododendron ponticum in Wales

Invasive plant species represent a serious threat to biodiversity, precipitating a sustained global effort to eradicate or at least control the spread of this phenomenon. Current distribution ranges of many invasive species are likely to be modified in the future by land cover and climate change. Thus, invasion management can be made more effective by forecasting the potential spread of invasive species. Rhododendron ponticum (L.) is an aggressive invasive species which appears well suited to western areas of the UK. We made use of MAXENT modelling environment to develop a current distribution model and to assess the likely effects of land cover and climatic conditions (LCCs) on future distribution of this species in the Snowdonia National park in Wales. Six global circulation models (GCMs) and two representative concentration pathways (RCPs), together with a land cover simulation for 2050 were used to investigate species’ response to future environmental conditions. Having considered a range of environmental variables as predictors and carried out AICc-based model selection, we find that under all LCCs considered in this study, the range of R. ponticum in Wales is likely to contract in the future. Land cover and topographic variables were found to be the most important predictors of the distribution of R. ponticum. This information, together with maps indicating future distribution trends will aid the development of mitigation practices to control R. ponticum

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology

Composición nutricional de la carne equina y grado de sustitución de la carne bovina por equina en expendios de la Ciudad de México

The degree of substitution of bovine meat for equine meat in different points of sale of the different boroughs of Mexico City was evaluated, and the benefits or similarities with bovine meat as a strong alternative of nutrients were identified. One hundred sixty-one samples of bovine meat were collected, which were subjected to near-infrared reflectance spectroscopy (NIR’s – Food Scan) to determine nutritional composition (moisture content, protein, fat and collagen), meat color (Hunter Lab L*, a* and b*) and polymorphism of repeated sequences to characterize the bovine or equine origin by polymerase chain reaction in agarose gels (PCR). The variables of nutritional composition and meat color were analyzed in a completely randomized design. It was found that nine of the samples were positive for equine meat and 152 samples were positive for bovine meat; resulting in that 5.59 % of bovine meat was replaced by equine meat in the commercialization centers in Mexico City. Likewise, the moisture, protein, fat and collagen content fluctuated between the samples from 73.1 to 75.1 %, from 22.0 to 23.5 %, from 2.0 to 2.3 %, and from 1.3 to 1.4 mg g-1, respectively; observing a slight increase (P0.05). It is concluded that the percentage of substitution of bovine meat for equine meat (5.59 %) is considered low and constitutes consumer fraud. However, equine meat has the potential to be a viable alternative for human consumption, as the nutritional composition was similar to bovine meat.Se evaluó el grado de sustitución de carne bovina por carne equina en distintos puntos de venta de las diferentes Alcaldías de la Ciudad de México, y se identificó las bondades o similitudes con la carne bovina como una fuerte alternativa de nutrientes. Se colectaron 161 muestras de carne de bovino que fueron sometidas a espectroscopia de reflectancia en el infrarrojo cercano (NIR´s – Food Scan) para determinar composición nutricional (contenido de humedad, proteína, grasa y colágeno), color de la carne (Hunter Lab L*, a* y b*) y polimorfismo de secuencias repetidas para caracterizar el origen bovino o equino por reacción en cadena de la polimerasa en geles de agarosa (PCR). Las variables de composición nutricional y color de la carne se analizaron en un diseño completamente al azar. Se encontró que nueve de las muestras dieron positivas para carne de equino y 152 muestras fueron positivas para carne de bovino; resultando que la carne de bovino fue sustituida el 5.59 % por carne equina en los centros de comercialización en la Ciudad de México. Asimismo, el contenido de humedad,  proteína, grasa  y  colágeno fluctuó  entre las muestras  de 73.1 a 75.1 %, de 22.0 a 23.5 %, de 2.0 a 2.3 %, y de 1.3 a 1.4 mg g-1, respectivamente; observando un ligero incremento (P0.05). Se concluye que el porcentaje de sustitución de la carne de bovino por carne equina (5.59 %) se considera bajo y constituye un fraude al consumidor. Sin embargo, la carne equina tiene un potencial de ser una alternativa viable para el consumo humano, ya que la composición nutricional fue similar a la carne de bovino

Evaluación de una metodología para determinar características de textura de tortilla de maíz (Zea mays L.)

La tortilla de maíz (Zea mays L.), es el principal alimento de la población Mexicana, con un consumo anual de 12 millones de toneladas. A pesar de su alto consumo, existe una gran variabilidad en las características de calidad de la tortilla producida comercialmente, principalmente las de textura. Para evaluar la textura de las tortillas se han reportado algunos métodos, pero los parámetros y valores obtenidos han sido muy variados y no comparten una base adecuada para su comparación. Además, la confiabilidad de los parámetros reportados, utilizando un texturómetro, tampoco ha sido evaluada. En este estudio se seleccionaron dos formas de la muestra, rectangular y probeta, así como la de varios parámetros de calidad obtenidos con el texturómetro (fuerza máxima, área total, área hasta fuerza máxima, elasticidad y elongación) y se evaluó su confiabilidad con base a su repetibilidad. De acuerdo a los resultados, la forma de "probeta" fue la más adecuada para las pruebas de tensión y elasticidad. Para la fuerza al corte, las dos formas resultaron con buena repetibilidad. La fuerza máxima fue el parámetro de mayor confiabilidad para las pruebas de tensión y corte, con una repetibilidad de 0.95 y 0.99 respectivamente. La elasticidad resultó con buena repetibilidad cuando la prueba se realizó con la forma de probeta (0.94). Utilizando el texturómetro y la forma de muestra tipo probeta, los parámetros determinados muestran alto grado de confiabilidad y facilitan la comparación de datos de textura para tortillas de maíz.Maize (Zea mays L.) tortilla is the primary staple food of the Mexican people, with annual consumption estimated at 12 millions tons. Despite this huge volume of consumption, tortillas are commercially produced with inconsistent quality, mainly in terms of texture characteristics. Different methods to evaluate the texture of maize tortillas have been reported, but the values obtained and their parameters have not yielded reliable results, largely because the methods used do not reflect homogeneous elements for comparison. In addition, evaluation of the reliability of methods for comparing tortilla texture as well as the equipment used has been difficult, as such information perhaps remains largely unpublished. In this study, the reliability of two tortilla sample shapes (rectangle and briquet) and some of the quality parameters (maximum force, total area under curve, area to reach maximum force, elasticity and elongation) from tensile and cut force tested with a texture meter were evaluated. According to the results, the briquet shape of the tortilla samples was better (than the rectangle shape) for determining tensile and elasticity. In regard to cutting force, both the rectangle and the briquet shape presented good repeatability. For tensile and cutting force curves, the maximum force was the parameter with the highest reliability, 0.95 and 0.99, respectively. The elasticity showed an adequate reliability with the tortilla briquet shape (0.94). The evaluated parameters with the texture meter and the sample shape type briquet, showed a high reliability degree what makes possible the comparison of maize tortilla texture data

EFFECT OF CITRIC ACID ADDITION ON AFLATOXIN DEGRADATION AND ON FUNCTIONAL PROPERTIES OF EXTRUDED SORGHUM PRODUCTS

Sorghum flour contaminated by aflatoxin at a concentration of 140 mu g.kg(-1) was extrusion-cooked in a single screw extruder with a temperature profile of 60-80-100 degrees C The moisture content (MC) of the flour was adjusted to 20, 25 and 30% by adding aqueous citric acid (CA) at concentrations of 0, 0.5, 1, 2, 4 and 8N. The temperature profile in combination with the MC and CA concentrations significantly affected the extent of aflatoxin reduction in the extruded sorghum; the maximum percentage of aflatoxin reduction was 35.5%. In extruded sorghum prepared with high MC and CA concentrations, the highest values in color difference (Delta E) and smallest values of viscosity were found. The expansion index was favored by higher MC and CA concentrations. The highest cutting force values were found in extruded products prepared with a higher MC, but there were no significant differences between those values and the different CA concentrations evaluated. Using moderate extrusion conditions in combination with higher concentrations of CA, products were obtained with acceptable pH, color viscosity, as well as with good textural and,functional properties.34425225

Exposure to p,p′-DDE Induces Morphological Changes and Activation of the PKCα-p38-C/EBPβ Pathway in Human Promyelocytic HL-60 Cells

Dichlorodiphenyldichloroethylene (p,p′-DDE), the most persistent metabolite of dichlorodiphenyltrichloroethane (DDT), is still present in the human population. Both are present in the bone marrow of patients with bone marrow disorders, but thus far there are no studies that assess the capability of p,p′-DDE to affect myeloid cells. The aim of this study was to determine the effect of p,p′-DDE on promyelocytic cell differentiation and intracellular pathways related to this event. p,p′-DDE induced morphological changes compatible with promyelocytic differentiation in a concentration-dependent manner. The p,p′-DDE effect on Ca2+i, C/EBPβ protein levels, PKCα and p38 activation, and the role of oxidative stress or PLA2 was assayed. Exposure to 1.9 μg/mL of p,p′-DDE increased Ca2+i, PKCα, p38, and C/EBPβ protein levels; the increase of nuclear C/EBPβ protein was dependent on p38. PKCα phosphorylation was dependent on PLA2 and p,p′-DDE-induced oxidative stress. p38 phosphorylation induced by p,p′-DDE was dependent on PLA2, PKC activation, and oxidative stress. These effects of p,p′-DDE at concentrations found in human bone marrow may induce alterations in immature myeloid cells and could affect their cellular homeostasis. In order to establish the risk from exposure to p,p′-DDE on the development of bone marrow disorders in humans, these effects deserve further study