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The blue corn-based products are considered functional foods due to their high concentration of anthocyanins. The aim of this study was to estimate the kinetic and thermodynamic parameters of the thermal degradation of anthocyanins from extruded nixtamalized corn products. A comparative study of anthocyanins thermal stability in these matrices in a buffer solution (pH 2.5) was investigated at different temperatures (60, 75 or 90 °C). Results showed the mechanism of anthocyanins degradation followed first-order reaction kinetics. The values of the reaction rate constant (k) were found to be in a range of 0.027-0.037 h-1 at 60 °C, 0.107-0.113 h-1 at 75 °C and 0.340-0.354 h-1 at 90 °C. The higher the k value was, the shorter the half-life time and D-value. The activation energy (Ea) and z-values were in the range of 75.1-89.2 kJ/mol and 28.8-35.1 °C, respectively. The coefficient Q10 indicated the reaction rate approximately doubles with every 10 °C temperature increase. ∆H, ∆S and ∆G indicated the degradation of anthocyanins was an endothermic and nonspontaneous reaction. Even the major susceptibility of the anthocyanins in extruded nixtamalized corn products at the time-temperature combination applied, there was not difference between flour and tortilla, this imply that most of the anthocyanins were degraded during the nixtamalization extrusion process and no significative further degradation occur in the cooking step. This study provides and advance in the knowledge on the effect of nixtamalization extrusion process and tortillas making on the stability of anthocyanins from blue corn. However, further studies are needed.
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Antocianinas , Zea mays , Antocianinas/análisis , Manipulación de Alimentos , Cinética , TermodinámicaRESUMEN
Sorghum is a cereal with little use in human diet; however, this grain can provide several nutrients and, additionally, has a high content of phenolic compounds concentrated in bran, which could be beneficial to human health due to its high antioxidant capacity. However, these bioactive compounds are bound within the cell wall matrix; it is necessary to release these compounds to take advantage of their antioxidant properties. The extrusion process increases the accessibility of bound phenolic compounds, breaking their bonds from the bran matrix. The aim of this study was to determine the optimal extrusion conditions for maximizing the phenolic compound content and antioxidant capacity of sorghum bran extrudate. The extrusion process factors evaluated were feed moisture (FM) from 25 to 35% and the fourth extrusion zone temperature (T) in the range of 140-180 °C. Analysis of variance and response surface analysis were used in the evaluation. The prediction coefficient, (FM)2, (T)2 and their interaction (FM)(T) significantly affected the free total phenolic compounds. The antioxidant capacity of the free total phenolic compounds was significantly affected by (FM)2 and (T)2. The optimal extrusion conditions were FM = 30% and T = 160 °C, which provided free total phenolic compounds with a value of 7428.95 µg GAE/g (predicted value: 7810.90 µg GAE/g) and antioxidant capacity with a value of 14.12 µmol TE/g (predicted value: 14.85 µmol TE/g). Results confirmed that extrusion process optimization was useful to increase the content of phenolic compounds and improved the antioxidant capacity of sorghum bran.
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Sorghum , Antioxidantes , Dieta , Grano Comestible , Humanos , FenolesRESUMEN
There is a little information about the effect of corn process conditions on the bioactive compounds of tortillas during gastrointestinal digestion. Tortillas elaborated with traditional and extrusion nixtamalization process were subjected to in vitro digestion. Extracts recovered from digestion were employed to determine the changes in phytochemicals, bioaccesibility and antioxidant capacity (DPPH, ABTS and FRAP). Digestion contributed to a greater solubilization of phenolic compounds in raw corn and tortillas, especially in the intestinal phase (311.4-583.2 mg GAE/100 g). With bioaccessibility indexes of 162.83 to 960.7 %. Intestinal phase affected the content of anthocyanins, reaching a lower bioaccessibility value than the found in undigested samples (17.90-29.91 %). Even though the traditional white tortilla showed the highest bioaccessibility values, blue tortilla showed a higher antioxidant activity in different phases of digestion. Both tortillas could function as prebiotic agents in the large intestine. Corn-based products are valuable as part of a healthy diet.
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Antioxidantes , Zea mays , Antocianinas , Fitoquímicos , DigestiónRESUMEN
Urea is the nitrogen-containing fertilizer most used in agricultural fields; however, the nutrient given by the urea is lost into the environment. The aim of this research was to determine the effect of two soil textures by applying a prolonged-release system of urea (PRSU) on the N losses. This research shows an important decrease of the nitrate and ammonium losses from 24.91 to 87.94%. Also, the microbiological population increases after the application of the PRSU. It was concluded that both soil textures presented the same loss-reduction pattern, where the N from the nitrates and ammonium was reduced in the leachates, increasing the quality of the soil and the microbial population in both soil textures after the PRSU application.
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This paper describes the design, construction and testing of an experimental setting, making it possible to study the endothelium under different pathophysiological conditions. This novel experimental approach allows the application of the following stimuli to an ex vivo vessel in a physiological bath: (a) a realistic intravascular pressure waveform defined by the user; (b) shear stress in the endothelial layer since, in addition to the pressure waveform, the flow through the vessel can be independently controlled by the user; (c) conditions of hypo/hyperoxia and hypo/hypercapnia in an intravascular circulating medium. These stimuli can be applied alone or in different combinations to study possible synergistic or antagonistic effects. The setting performance is illustrated by a proof of concept in an ex vivo rabbit aorta. The experimental setting is easy to build by using very low-cost materials widely available. Online Supplement files provide all the technical information (e.g., circuits, codes, 3D printer drivers) following an open-source hardware approach for free replication.
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The aim of this study was to compare the physicochemical, rheological, and morphological characteristics of corn, nixtamalized flour, masa, and tortillas from the traditional nixtamalization process (TNP) and the extrusion nixtamalization process (ENP) and their relationship with starch. The traditional and extrusion processes were carried out using the same variety of corn. From both processes, samples of ground corn, nixtamalized flour, masa, and tortillas were obtained. The extrusion process produced corn flour with particle sizes smaller (particle size index, PSI = 51) than that of flour produced by the traditional nixtamalization process (PSI = 44). Masa from the TNP showed higher modulus of elasticity (G') and viscosity (G â³) values than that off masa from the ENP. Furthermore, in a temperature sweep test, masa from the TNP showed a peak in G' and G â³, while the masa from the ENP did not display these peaks. The ENP-produced tortillas had higher resistant starch contents and comparable firmness and rollability to those from the TNP but lower quality parameter values. A comparison of the products' physicochemical properties obtained by the two processes shows the importance of controlling the damage to starch during the milling and extrusion processes to obtain tortillas of better quality. For the first time, we propose the measurement of the viscoelastic parameters G' and G â³ in temperature sweep mode to monitor changes in the degree of starch damage.
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The aim of this study was to evaluate the effect of extrusion factors on the properties of extruded nixtamalized corn flours (ENCFs), determine the optimal conditions, and produce a tortilla with texture and nutraceutical characteristics acceptable for consumers. The processing factors used were feed moisture (FM, 15 to 30%), extruder temperature (T, 70 to 110 °C), and screw speed (SS, 50 to 145 rpm). The properties evaluated in the flours were total anthocyanins (TA), subjective water absorption capacity, and peak viscosity (PV). Response surface methodology and analysis of variance were used in the evaluation. The linear and quadratic terms of FM had a greater effect on all evaluated parameters. The optimization was performed using the numerical method of global desirability. The response variables that were optimized in the ENCF were TAs (maximize) and PV (maximize). The optimal region was the following: FM (18.17%), T (92.03 °C), and SS (76.61 rpm). The experimental value for the TA in the optimized ENCF was 226.07 mg/kg, and the PV was 1063.9 cP. The results of this study could help develop nixtamalized corn flours with desirable characteristics to make tortillas using the extrusion process. PRACTICAL APPLICATION: The results obtained would be useful for the tortilla industry, developing nixtamalized corn flours with desirable characteristics to make healthy tortillas using the extrusion process, with minimum losses in biologically active compounds such as anthocyanins (health promoters) without affect negatively the eating quality of the product (good texture).
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Antocianinas/análisis , Harina/análisis , Manipulación de Alimentos/métodos , Zea mays/química , Antocianinas/aislamiento & purificación , Pan/análisis , Color , Temperatura , Viscosidad , Agua/análisisRESUMEN
The non-enzymatic reaction between reducing sugars and proteins, known as glycation, has received increased attention from nutritional and medical research. In addition, there is a large interest in obtaining glycoconjugates of pure well-characterized oligosaccharides for biological research. In this study, glycation of bovine serum albumin (BSA) by d-glucose, d-galactose and d-lactose under dry-heat at 60 degrees C for 30, 60, 120, 180 or 240 min was assessed and the glycated products studied in order to establish their biological recognition by lectins. BSA glycation was monitored using gel electrophoresis, determination of available amino groups and lectin binding assays. The BSA molecular mass increase and glycation sites were investigated by mass spectrometry and through digestion with trypsin and chymotrypsin. Depending on time and type of sugar, differences in BSA conjugation were achieved. Modified BSA revealed reduction of amino groups' availability and slower migration through SDS/PAGE. d-galactose was more reactive than d-glucose or d-lactose, leading to the coupling of 10, 3 and 1 sugar residues, respectively, after 120 minutes of reaction. BSA lysines (K) were the preferred modified amino acids; both K256 and K420 appeared the most available for conjugation. Only BSA-lactose showed biological recognition by specific lectins.
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Albúmina Sérica Bovina/química , Albúmina Sérica/química , Secuencia de Aminoácidos , Animales , Bovinos , Electroforesis en Gel de Poliacrilamida , Galactosa/química , Glucosa/química , Productos Finales de Glicación Avanzada , Glicoproteínas/química , Glicoproteínas/genética , Glicoproteínas/metabolismo , Glicosilación , Calor , Técnicas In Vitro , Lactosa/química , Lectinas/metabolismo , Reacción de Maillard , Datos de Secuencia Molecular , Peso Molecular , Fragmentos de Péptidos/química , Fragmentos de Péptidos/genética , Unión Proteica , Albúmina Sérica/genética , Albúmina Sérica/metabolismo , Albúmina Sérica Bovina/genética , Albúmina Sérica Bovina/metabolismo , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Albúmina Sérica GlicadaRESUMEN
Resumen El aumento de la resistencia a los antibióticos por parte de bacterias patógenas ha motivado la búsqueda de alternativas para disminuir su utilización. Dentro de las opciones propuestas se encuentra la terapia de antiadherencia, en la cual se utilizan moléculas análogas a los glicoepítopes que son reconocidos por las bacterias para impedir la unión de éstas al tejido celular. En este estudio se llevó a cabo la obtención de glicoconjugados por medio de la reacción de Maillard partiendo de albúmina sérica bovina (BSA) y oligosacáridos de quitosano (oligosacáridos sin ultrafiltrar, ultrafiltrados y ultrafiltrados acetilados), en proporción 1:1 (p/p) a tres temperaturas de incubación (50, 60 y 70 °C) por 30 min. La caracterización de los conjugados sintetizados se realizó utilizando electroforesis (SDS-PAGE), espectroscopía de infrarrojo y espectroscopía de fluorescencia. Se realizaron ensayos de reconocimiento usando aglutinina de germen de trigo (WGA) y bacterias [Escherichia coli (K88ac y K88+)]. La caracterización por medio de electroforesis y espectroscopía de infrarrojo evidenció la unión de los oligosacáridos de quitosano a la estructura de la BSA. Además, los ensayos evidenciaron el reconocimiento de las moléculas sintetizadas tanto por la lectina WGA como por las bacterias. Los glicoconjugados sintetizados sin ultrafiltrar ni acetilar mostraron resultados muy favorables en el reconocimiento por ambas bacterias, lo que constituye una ventaja práctica, ya que su implementación a mayor escala reduciría costos de producción
Abstract The increase in antibiotic resistance by pathogenic bacteria has motivated the search for alternatives to reduce the use of antibiotics. Among these alternatives is anti-adhesion therapy, in which molecules that mimic the glycoepitopes that recognise bacteria are used to prevent their binding to cellular tissue. In this study, glycoconjugates were obtained by means of the Maillard reaction starting from bovine serum albumin (BSA) and chitosan oligosaccharides (unfiltered oligosaccharides, ultrafiltered and acetylated ultrafiltered), in a ratio of 1:1 (w/w) at three incubation temperatures (50, 60 and 70 °C) per 30 min. The characterisation was performed using the techniques of electrophoresis (SDS-PAGE), infrared spectroscopy and fluorescence spectroscopy. Recognition assays were performed using wheat germ agglutinin (WGA) and Escherichia coli bacteria (K88ac and K88+). Characterisation by electrophoresis and infrared spectroscopy demonstrated the binding of chitosan oligosaccharides to the structure of BSA. In addition, the tests showed the recognition of the molecules synthesised by both the WGA lectin and the E. coli bacteria. The glycoconjugates synthesised without ultrafiltration or acetylation showed very favourable results in recognition with both bacteria, which is an advantage, since its implementation on a larger scale would reduce production costs.
Resumo O aumento da resistência aos antibióticos por bactérias patogênicas tem motivado a busca de alternativas para reduzir seu uso. Entre essas alternativas está a terapia anti-adesão, na qual são utilizadas moléculas análogas aos glicoepítopos que são reconhecidas pelas bactérias para impedir sua união ao tecido celular. Neste estudo, os glicoconjugados foram obtidos por meio da reação de Maillard a partir de albumina sérica bovina (BSA) e oligossacarídeos de quitosana (oligossacarídeos não ultrafiltrados, ultrafiltrados e acetilados ultrafiltrados), na proporção de 1:1 (p/p) em três temperaturas de incubação (50, 60 e 70 °C) durante 30 min. A caracterização dos conjugados sintetizados foi realizada utilizando a eletroforese (SDS-PAGE), espectroscopia de infravermelho e espectroscopia de fluorescência. Os ensaios de reconhecimento foram realizados utilizando aglutinina de germe de trigo (WGA) e bactérias [Escherichia coli (K88ac e K88+)]. A caracterização por meio de eletroforese e espectroscopia de infravermelho demonstrou a união dos oligossacarídeos de quitosana à estrutura da BSA. Além disso, os testes evidenciaram o reconhecimento das moléculas sintetizadas tanto pela lectina WGA quanto pelas bactérias. Os glicoconjugados sintetizados sem ultrafiltração ou acetilação apresentaram resultados muito favoráveis no reconhecimento por ambas as bactérias, o que é uma vantagem, visto que sua implementação em maior escala reduziria custos de produção.
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El arándano (Vaccinium corymbosum L.) posee un alto contenido de compuestos fenólicos los cuales han sido estudiados principalmente por su actividad antioxidante, antiobesogénica, antiinflamatoria, entre otras. Objetivo. Evaluar el efecto de la digestión gastrointestinal in vitro sobre la bioaccesibilidad de compuestos fenólicos y actividad antioxidante de una formulación nutracéutica de arándano (cápsula), comparado con arándano fresco y polvo. Materiales y métodos. Se obtuvieron extractos metanólicos de muestras de arándano fresco y liofilizado y se determinó su contenido de fenoles, flavonoides y antocianinas totales, así como también actividad antioxidante. Se llevó a cabo un ensayo de simulación de digestión gastrointestinal para evaluar la bioaccesibilidad de los compuestos fenólicos presentes en las muestras. Resultados. Los resultados mostraron que la digestión gástrica de arándano en polvo y en cápsula promovió una mayor bioaccesibilidad de fenoles (42% y 40%), flavonoides (52% y 33%) y antocianinas (45% y 40%) comparado con digestos de arándano fresco. Posterior a la digestión intestinal, la bioaccesibilidad de fenoles (63%) y flavonoides (67%) fue mayor en la cápsula de arándano comparada con su contraparte arándano en polvo. Las condiciones de digestión intestinal afectaron negativamente la bioaccesibilidad de las antocianinas independientemente del tipo de muestra evaluada. Conclusión. Las condiciones de digestión gástrica promueven una mayor estabilidad de los compuestos fenólicos en arándano en polvo y en cápsula lo que pudiera ser relevante para el mantenimiento de un ambiente antioxidante a este nivel. Las condiciones de digestión intestinal afectaron de manera particular a los compuestos fenólicos de arándano fresco y polvo, pero no a la cápsula, lo que puede sugerir que el encapsulamiento protegió de las condiciones alcalinas a los fenoles presentes. Se sugieren estudios posteriores sobre absorción in vitro de los componentes remanentes en intestino y sus posibles efectos sobre biomarcadores de estrés oxidativo en modelos in vivo(AU)
Blueberry (Vaccinium corymbosum L.) has a high content of phenolic compounds which have been studied mainly for their antioxidant, antiobesogenic, anti-inflammatory activity, among others. Objetive. The objective of the present study was to evaluate the effect of in vitro gastrointestinal digestion on the bioaccessibility of phenolic compounds and antioxidant activity of a nutraceutical formulation of blueberry (capsule), compared to fresh and powder blueberry. Materials and methods. Methanolic extracts of fresh and lyophilized blueberry were obtained and determined its total phenols, flavonoids, anthocyanins content, as well as antioxidant activity. A gastrointestinal digestion simulation test also was carried out to assess the bioaccessibility of the phenolic compounds found in samples. Results. The results showed that gastric digestion of powder and capsule blueberry promoted greater bioaccessibility of phenols (42% and 40%), flavonoids (52% and 33%) and anthocyanins (45% and 40%), compared to fresh blueberry digests. After intestinal digestion, the bioaccessibility of phenols (63%) and flavonoids (67%) was higher in the blueberry capsule compared to its powdered blueberry counterpart. The intestinal digestion conditions negatively affected the bioaccessibility of anthocyanins regardless of the type of sample evaluated. Conclusion. Gastric digestion conditions promote greater stability of phenolic compounds in powdered and capsule blueberries, which could be relevant for the maintenance of an antioxidant environment at this level. The intestinal digestion conditions particularly affected the phenolic compounds of fresh and lyophilized blueberry, but not the capsule, which may suggest that encapsulation protected the phenols present from alkaline conditions. Further studies on in vitro absorption of the remaining components in the intestine and their possible effects on oxidative stress biomarkers in in vivo models are suggested(AU)
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Taninos , Flavonoides , Arándanos Azules (Planta) , Compuestos Fenólicos , Absorción Gastrointestinal , Técnicas In Vitro , Enfermedad Crónica , Digestión , LiofilizaciónRESUMEN
PURPOSE: Storage and ionizing radiation of human red blood cells (RBC) produce alterations on RBC membranes and modify their normal shape and functionality. We investigated early morphological and biochemical changes in RBC due to those stressing agents at the nanoscale level and their impact on blood quality. MATERIALS AND METHODS: Whole blood samples from healthy donors were γ-irradiated with 15, 25, 35, and 50 Gy. Non-irradiated and non-stored RBC were used as control samples. Irradiated blood samples were stored separately at 4 °C and analyzed immediately and after 5 and 13 d. Atomic force microscopy (AFM), osmotic fragility and Raman spectroscopy were used to detect morphological and biochemical changes. RESULTS: RBC function is challenged by both irradiation and storage. The storage procedure caused nanometric variations over the surface of RBC membrane for both irradiated and non-irradiated cells. The membrane of RBC became more fragile, while the biochemical fingerprint of hemoglobin (Hb) remained unaltered. CONCLUSIONS: Our work shows that the irradiation procedure leads to an increase in the number and size of nanovesicles along with the dose. The functionality of RBC can be affected from changes in the roughness, becoming more fragile and susceptible to breakage.
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Membrana Eritrocítica/efectos de la radiación , Rayos gamma/efectos adversos , Nanotecnología , Adulto , Humanos , Fragilidad Osmótica/efectos de la radiación , Adulto JovenRESUMEN
BACKGROUND: Thyroid nodules in children and adolescents may be associated to malignant neoplasms. Although thyroid cancer is a rare event in this age group, delayed diagnosis is associated to metastatic, regional or lung disease, but even in these circumstances appropriate treatment may be followed by good prognosis. We decided to review the clinical course of these patients in our hospital from 1980 to 2001. METHODS: We found fifteen patients younger than 18 years diagnosed with thyroid carcinoma, which had been followed by at least 12 months, with a mean of 95 months and a maximal of 10 years. All patients were treated by surgery and 131 iodine, and followed by scans, ultrasound and thyroglobulin analysis. RESULTS: The patients group were thirteen females and two males. At diagnosis, seven patients (46.7o%) had metastatic regional disease and eight had a thyroid nodule. Total thyroidectomy with a modified neck dissection and 131 iodine was the initial treatment for patients with regional disease and subtotal thyroidectomy and 131 iodine in the follow-up to treat the thyroid bed or metastases was the treatment for patients with localized disease. All patients had a histologic pattern of papillary carcinoma. Nine patients (60%) had local recurrence in a mean follow-up of 37 months, one patient that had been previously treated by total thyroidectomy and all patients that were treated by subtotal thyroidectomy, however, all responded to the complementary treatment. At this moment the mean follow up is 95 months and all the patients have survived. CONCLUSIONS: In our experience thyroid cancer in children and adolescents is a rare event whose delayed diagnosis is associated to regional lymph node or lung metastases. Subtotal thyroidectomy was associated to disease progression to metastases, but complementary treatment was successful and all patients have survived.
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Neoplasias de la Tiroides , Adolescente , Niño , Femenino , Humanos , Masculino , Neoplasias de la Tiroides/diagnóstico , Neoplasias de la Tiroides/cirugíaRESUMEN
Characterization of cookies made with deseeded grape pomace. The objective of this study was to evaluate deseeded grape pomace as a potential ingredient to elaborate some food products. Cookies were made with flour containing four levels of deseeded grape pomace (0, 5, 7.5 and 10%). Moisture, protein, ashes, fat, tannins and dietary fiber contents were determined in both the deseeded of grape pomace and the cookies. Besides, color, sensorial acceptability and biological evaluations of Net Protein Ratio (NPR), Apparent Digestibility (AD) and True Digestibility (TD) of Protein were determined to the cookies. Substantial amounts of dietary fiber and ashes were found in both the deseeded grape pomace and the cookies. Total dietary fiber increased while adding more deseeded grape pomace. Cookies were well accepted as observed in the sensory evaluation, showing no significative differences among the four levels of deseeded grape pomace addition. The addition of deseeded grape pomace imparted a darker color to the cookies. The dark color was greater in the samples containing more fiber which was indicated by the lower L color value. Regarding nutritional analysis, the higher the deseeded grape pomace addition, the lower the NPR, AD, and TD values. The NPR was affected in greater degree, although these differences were not significant. It is possible to use deseeded grape pomace as an ingredient to make high fiber cookies with acceptable sensorial attributes.
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Fibras de la Dieta/análisis , Alimentos , Vitis , Análisis de los AlimentosRESUMEN
Enterotoxigenic (ETEC) Escherichia coli (E. coli) causes traveller's diarrhoea and high mortality among baby animals. ETEC adhesion is mediated by lectins (adhesins) that bind to glycoconjugates on the surface of host cells. Glycans that compete for adhesion could be used for disease prevention. Neoglycans of porcine albumin (PSA) that were conjugated with prebiotic galactooligosaccharides (GOS) were synthesised using the Maillard reaction. PSA glycation was confirmed by a reduction in the number of available free amino groups, decreased tryptophan intrinsic fluorescence, increased molecular mass and Ricinus communis lectin recognition. The adhesion of four ETEC strains (E. coli H10407, CFA(+), K99 and K88) to PSA-GOS was examined by an enzyme-linked lectin assay. E. coli K88 bound to PSA-GOS with greater affinity (P<0.05) than did E. coli H10407, CFA(+) and K99. In addition, PSA-GOS partially inhibited the adherence of the K88 strain to intestinal mucins. Pig ETEC strain was unable to ferment galactooligosaccharide-neoglycans. These results suggest that neoglycans obtained by the Maillard reaction may serve in the prophylaxis of ETEC K88 diarrhoea.
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Adhesión Bacteriana , Escherichia coli Enterotoxigénica/fisiología , Infecciones por Escherichia coli/veterinaria , Oligosacáridos/metabolismo , Polisacáridos/metabolismo , Prebióticos/microbiología , Enfermedades de los Porcinos/microbiología , Albúminas/química , Albúminas/metabolismo , Animales , Línea Celular , Escherichia coli Enterotoxigénica/química , Infecciones por Escherichia coli/metabolismo , Infecciones por Escherichia coli/microbiología , Glicosilación , Mucosa Intestinal/metabolismo , Intestinos/microbiología , Cinética , Reacción de Maillard , Mucinas/metabolismo , Oligosacáridos/química , Polisacáridos/química , Prebióticos/análisis , Sus scrofa , Porcinos , Enfermedades de los Porcinos/metabolismoRESUMEN
Abstract Bread is one of the most consumed foods in the world, and alternatives have been sought to extend its shell life, and freezing is one of the most popular methods. The purpose of this study was to evaluate the effect of freezing rate and trehalose concentration on the fermentative and viscoelastic properties of dough and bread quality. Dough was prepared and trehalose was added at three concentrations (0, 400, 800 ppm); dough was pre fermented and frozen at two freezing rates then stored for 42 days. Frozen dough samples were thawed every two weeks. CO2 production and elastic and viscous modulus were determined. In addition, bread was elaborated and specific volume and firmness were evaluated. High trehalose concentrations (400 and 800 ppm) produced dough with the best viscoelastic and fermentative properties. Greater bread volume and less firmness were observed when a slow freezing rate (-.14 °C/min) was employed.
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Chitin neoglycoconjugates (BSA-CO) were obtained by the conjugation of bovine serum albumin (BSA) with chitin oligosaccharides (CO) through the Maillard reaction (nonenzymatic glycation). CO produced by acid hydrolysis of chitin were fractionated using an ultrafiltration membrane system (1-3 kDa cutoff). The Maillard reaction was carried out by heating a freeze-dried mixture containing BSA and CO at 60 °C (under 43% relative humidity for 6 and 12 h). BSA-CO were characterized by available amino groups content, intrinsic tryptophan emission spectra, gel electrophoresis, and mass spectrometry. Biological assays included interaction with wheat germ agglutinin (WGA) and with bacterial adhesins of Escherichia coli K88+ and Salmonella choleraesuis. Glycation of BSA was revealed by reduction of available amino groups and fluorescence intensity and also retarded migration through SDS-PAGE. Conjugation of BSA with chitin oligomers appeared to be time dependent and was confirmed by mass spectrometry, by which molecular mass increase for monomers and dimers was observed. Monomers were estimated to contain either one or two glycation sites (at 6 and 12 h of treatment, respectively), with one or two tetrasaccharide units attached. Consequently, dimers showed two or four glycation sites. BSA-CO presented biological recognition by WGA and E. coli K88+ and S. cholerasuis adhesins. The strategy used in this work represents a simple method to obtain glycoconjugates to study applications involving protein-carbohydrate recognition.
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Quitina/química , Oligosacáridos/química , Albúmina Sérica Bovina/química , Animales , Bovinos , Reacción de MaillardRESUMEN
Glycoconjugates consist of glycans attached to proteins or lipids. Glycans are involved in important biological functions such as trafficking of glycoconjugates, mediation, and modulation of cell adhesion and signaling. This study was conducted to obtain neoglycoconjugates containing a large number of carbohydrates, added through the condensation of reducing sugars with protein amino groups, whose structures were recognized by lectins. Neoglycoconjugates (BSA-Lac) of bovine serum albumin (BSA) with d-lactose were obtained using two sets of glycation conditions, each previously selected by its ability to glycate proteins extensively. The conditions included dry heat at 60 degrees C (for 7, 14, 21, and 28 days) and wet heat in 43% relative humidity (RH) at 50 degrees C (for 5, 10, 15, and 20 h). Products were characterized by gel electrophoresis, tryptophan fluorescence emission spectra, mass spectrometry, free amino group analysis, and their biological recognition established by a galactose-specific lectin and Escherichia coli K88 adhesins. BSA-Lac when compared to BSA revealed an increase in monomer mass due to addition of either 13 (dry heat) or 14 (wet heat) lactoses and formation of polymers (in wet conditions). All BSA-Lac products showed reduced intensity of intrinsic fluorescence, decreased amino groups' availability, and were recognized by Ricinus communis I lectin (RCAI) and by E. coli K88 adhesins. Overall, glycation using both conditions was time-dependent, but greater biorecognition was observed with wet-heat products, due to a higher global glycation and/or to the carbohydrate accessibility. The strategy used in this work represents a simple procedure to obtain glycoconjugates that could be used for recognition studies in biological systems.
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Adhesinas Bacterianas/química , Antígenos Bacterianos/química , Proteínas de Escherichia coli/química , Proteínas Fimbrias/química , Lactosa/química , Lectinas/química , Albúmina Sérica Bovina/química , Adhesinas Bacterianas/metabolismo , Animales , Antígenos Bacterianos/metabolismo , Bovinos , Células Inmovilizadas/química , Células Inmovilizadas/metabolismo , Escherichia coli/química , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteínas Fimbrias/metabolismo , Glicosilación , Proteínas de Plantas/química , Unión Proteica , Ricinus/química , TemperaturaRESUMEN
La técnica convencional (TC) que usa alcohol como agente deshidratante, es un método útil en los laboratorios de Histología y Anatomía Patológica. Recientemente, un nuevo método simplificado con acetona (TA) fué diseñado en un intento por reducir el tiempo de procesamiento de los tejidos (de 12 a 4 horas), el costo de reactivos, y como un factor importante para tener un diagnóstico veraz y rápido. En este trabajo se compararon los parámetros histológicos e inmunohistoquímicos en muestras de cáncer de mama, colon y riñón tratadas con ambos métodos. Los cortes fueron teñidos con H & E o tricrómico de Masson. También se llevó a cabo inmunohistoquímica con anticuerpos especificos para la identificación de citoqueratinas AE1/AE3, el receptor de estrógeno y receptor de progesterona. Se realizó un estudio ciego por tres especialistas en morfológía, quienes evaluaron la tinción nuclear, tinción del citoplasma y friabilidad o cambios en la estructura tisular. La especificidad y sensibilidad de la unión de los anticuerpos también fueron evaluadas. Los valores obtenidos para cada parámetro se analizaron estadísticamente con la prueba t de Student. Nuestros resultados muestran que los métodos de TC y TA no modificaron características histológicas como el patrón de tinción, ni se detectaron cambios tisulares. La positividad de la inmunohistoquímica fué similar para ambos métodos. No se observó diferencia estadística entre TC y TA. Nuestros resultados sugieren que la aplicación de la TA no modificó las propiedades histológicas e inmunohistoquímicas y que podría ser un método útil en el análisis morfológico.
The conventional technique (CT) using alcohol as a drying agent, is a useful method of histology and pathology in the laboratory. Recently, a new simplified method with acetone (TA) was designed in an attempt to reduce the processing time of the tissues (12 to 4 hours), the cost of reagents, and as an important factor to have an accurate and prompt diagnosis . This study compared the histological and immunohistochemical parameters in breast cancer, colon and kidney specimens treated with both methods. The sections were stained with H & E or Masson trichrome. Immunohistochemistry study with antibodies specific for the identification of cytokeratin AE1/AE3, the estrogen receptor and progesterone receptor was also carried out. Blind study was conducted by three specialists in morphology, who evaluated the nuclear staining, staining of the cytoplasm and friability or changes in tissue structure. The specificity and sensitivity of antibody binding were also evaluated. The values obtained for each parameter were statistically analyzed with Student t test. Our results show that the methods of CT and TA did not alter histological features as the pattern of staining, and tissue changes were detected. Immunohistochemical positivity was similar for both methods. There was no statistical difference between TC and TA. Our results suggest that implementation of the TA did not alter the histological and immunohistochemical properties and could be a useful method for morphological analysis.
Asunto(s)
Humanos , Acetona/química , Tejidos/patología , Técnicas Histológicas/métodos , Biopsia , Inmunohistoquímica , Receptores de Progesterona , Sensibilidad y Especificidad , Colon/patología , Deshidratación , Glándulas Mamarias Humanas/patología , Queratinas , Riñón/patología , Anticuerpos , NeoplasiasRESUMEN
En el presente estudio se ha diseñado y aplicado un programa lúdico-educativo con el fin de estimular el lenguaje de niños de último curso de educación infantil con y sin dificultad específica. Este programa pretende responder a la necesidad de herramientas en el aula que, de forma atractiva y dinámica, actúen sobre las dificultades que pueden aparecer durante el desarrollo del lenguaje oral de los niños. Para ello, se empleó un diseño pre-post con una muestra de 25 alumnos de tercer curso de educación infantil. Las evaluaciones se realizaron a través de un registro de observación del lenguaje y de la Prueba de lenguaje oral de Navarra revisada. Las actividades del programa lúdico están basadas en el juego dirigido y se centran en aspectos como la atención, el reconocimiento visual, la lateralidad, el ritmo y la fluidez del habla, la discriminación auditiva, etc. Su duración ha sido de un mes, con 2 sesiones semanales de 45 min. Los resultados reflejan diferencias estadísticamente significativas en la mayoría de las variables objeto de intervención. Si bien se trata de un estudio piloto, los resultados parecen apoyar la utilidad de intervenciones breves de tipo lúdico-educativo aplicadas a nivel grupal en el contexto escolar para la estimulación del lenguaje (AU)
In the present study, an educational play-based program was designed and implemented to stimulate the language of children with or without specific difficulties in the last year of primary education. This program aimed to respond to the need for dynamic tools in the classroom to correct difficulties that may arise during the development of children's oral language. To do this, a pre-post design was used with a sample of 25 students in their third year of primary education. Evaluations were performed by the Revised Navarre oral language test and an observational procedure specifically designed for this study. The program's activities were based on directed play and focused on aspects such as attention, visual recognition, laterality, rhythm and fluency of speech, auditory discrimination, etc. The program lasted for 1 month with two weekly sessions of 45 min each.Statistically significant differences were found in most of the variables. Although this was a pilot study, the results seem to support the usefulness of brief interventions for language stimulation applied at the group level in schools (AU)
Asunto(s)
Humanos , Masculino , Femenino , Preescolar , Niño , Proyectos Piloto , Lenguaje Infantil , Estudios del Lenguaje/tendencias , Desarrollo del Lenguaje , Juego e Implementos de Juego/psicología , Ludoterapia/métodos , Ludoterapia/tendencias , Pruebas del Lenguaje/estadística & datos numéricos , Pruebas del Lenguaje/normas , Terapia del Lenguaje/métodos , Terapia del Lenguaje/normas , Ludoterapia/organización & administración , Ludoterapia/estadística & datos numéricos , Ludoterapia/normasRESUMEN
El objetivo del presente estudio fue evaluar la cascarilla de orujo de uva como posible ingrediente en la elaboración de productos para consumo humano, para lo cual se elaboraron galletas con cuatro niveles de adición de cascarilla (0, 5, 7.5 y 10 por ciento). Se determinó el contenido de humedad, proteína, cenizas, grasa, taninos y fibra dietaria tanto en cascarilla de orujo de uva como en galletas. Además, en galletas se llevó a cabo la medición de color, prueba de aceptación sensorial y las evaluaciones biológicas de Razón Neta de Proteína (NPR) y Digestibilidad Aparente (DA) y Verdadera de Proteína (DV). Se encontraron altos contenidos de fibra dietética y cenizas tanto en cascarilla de orujo como en galletas. La fibra dietética total aumentó al incrementarse la adición de cascarilla de orujo. El contenido de taninos encontrado en cascarilla disminuyó significativamente en galletas. Se observó un alto nivel de agrado de las galletas en la evaluación sensorial, no mostrando diferencias significativas entre los cuatro niveles de adición. En la medición de color, la intensidad del color fue aumentando a medida que se agregó más cascarilla. Con respecto a las evaluaciones biológicas, al aumentarse el porcentaje de adición de cascarilla de orujo fueron disminuyendo los valores de NPR, DA y DV, afectándose en mayor grado el NPR, aunque estadísticamente, esta diferencia no fue significativa. Se concluye, que es posible utilizar, la cascarilla de orujo de uva como ingrediente para la elaboración de galletas con alto contenido de fibra dietaria y un nivel de agrado aceptable