RESUMO
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 , Mirtilos Azuis (Planta) , Compostos Fenólicos , Absorção Gastrointestinal , Técnicas In Vitro , Doença Crônica , Digestão , LiofilizaçãoRESUMO
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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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 , Grão Comestível , Humanos , FenóisRESUMO
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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Aderência Bacteriana , Escherichia coli Enterotoxigênica/fisiologia , Infecções por Escherichia coli/veterinária , Oligossacarídeos/metabolismo , Polissacarídeos/metabolismo , Prebióticos/microbiologia , Doenças dos Suínos/microbiologia , Albuminas/química , Albuminas/metabolismo , Animais , Linhagem Celular , Escherichia coli Enterotoxigênica/química , Infecções por Escherichia coli/metabolismo , Infecções por Escherichia coli/microbiologia , Glicosilação , Mucosa Intestinal/metabolismo , Intestinos/microbiologia , Cinética , Reação de Maillard , Mucinas/metabolismo , Oligossacarídeos/química , Polissacarídeos/química , Prebióticos/análise , Sus scrofa , Suínos , Doenças dos Suínos/metabolismoRESUMO
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.