Efeito da pressão de vácuo na carne de peixe Yamú (Brycon amazonicus) durante o armazenamento refrigerado

This study aimed to assess the cryoprotectant effect of vacuum packaging (35 and 45 kPa) on cold preserved (0 °C and -18 °C) fillets of Yamú (Brycon amazonicus), during 5 days of storage. We analyzed the physicochemical and microbiological changes in the fillets during storage time. Yamú’s water holding capacity, nitrogenated bases content (TVB-N) and texture (N) were affected (p ≤ 0.05) by time and temperature. Bacterial colonies in fillets did not represent a risk for human health after five days of storage. In conclusion, vacuum packing positively (p ≤ 0.05) reduces the effect of cold over Yamú fillets properties.O objetivo deste trabalho foi avaliar o efeito crioprotetor de embalagens a vácuo (35 e 45 kPa) em filés de Yamú (Brycon amazonicus) conservados a frio (0 °C e -18 °C), durante cinco dias de armazenamento. As alterações físico-químicas e microbiológicas foram analisadas nos filés durante o armazenamento. A capacidade de retenção de água, o teor de base nitrogenada (BTV-N) e a textura (N) foram influenciados (p ≤ 0,05) pelo tempo e pela temperatura. Colônias bacterianas em filés não representaram risco à saúde humana após cinco dias de armazenamento. O uso de embalagem a vácuo apresentou efeito significativo positivo (p ≤ 0,05), reduzindo o efeito do frio sobre as propriedades dos filés

Free-form architectural envelopes: Digital processes opportunities of industrial production at a reasonable price

Free-form architecture is one of the major challenges for architects, engineers, and the building industry. This is due to the inherent difficulty of manufacturing double curvature facades at reasonable prices and quality. This paper discusses the possibilities of manufacturing free-form facade panels for architectural envelopes supported by recent advances in CAD/CAM systems and digital processes. These methods allow for no-mould processes, thus reducing the final price. Examples of actual constructions will be presented to prove the viability of computer numerically controlled (CNC) fabrication technologies. Scientific literature will be reviewed. Promising fabrication methods (additive, subtractive, forming) to accomplish this proposal will be discussed. This research will provide valuable information regarding the feasibility of manufacturing free-form panels for architectural envelopes at lower prices

Technical evolution of 3d modular construction from the nineteenth century to world war II

3D Modular construction is poorly known and scarcely published in technical literature. In spite of that there are an increasing number of manufacturers offering their products in different countries. This method has largely evolved from early examples such as the American Gold Rush prefabrication in the nineteenth century, the Sears precut homes or Voisin´s prototypes for modular homes, to the end of the first half of the twentieth century. In this period a non negligible number of attempts in 3D modular construction have been carried out, ranging from theoretical proposals to several hundred or thousand units produced. Selected examples of modular architecture will be analyses in order to illustrate its technical evolution, concerning materials, structure, transportation and on site assembly. Success and failure factors of the different systems will be discussed. Conclusions about building criteria shown in them and their applicability in current architecture will be drawn

Nuevos métodos de fabricación digital de paneles de GRC de forma libre

Free-form GRC panels are widely used in lightweight facade elements. Such panels can be manufactured through a variety of methods. Nevertheless, its advantages such as moldability, durability and lightness, are penalized by the high price of the corresponding molds, especially if there is not a sufficient repetition of units. New digital technologies enable innovative possibilities in the field of construction and manufacture of molds with complex geometries. In this paper, a series of manufacturing methods for free-form GRC panels are presented. Advantages and drawbacks of these methods are discussed, especially the role played by the mold and its economic impact. Finally, conclusions of this analysis about its technical feasibility and possibilities are drawn.Los paneles de forma libre de GRC son de gran aplicación en elementos de fachadas ligeras. Dichos paneles pueden fabricarse a través de una gran variedad de procesos. Sin embargo, a pesar de sus ventajas como la moldeabilidad, durabilidad y ligereza, se ven penalizados por el elevado precio de los correspondientes moldes, sobre todo si no hay una repetición suficiente de las piezas y la forma del panel difiere de lo convencional. Las nuevas tecnologías digitales permiten diversas posibilidades en el campo de la construcción y la producción de moldes con geometrías complejas. En el presente artículo se presenta una serie de métodos recientes en la fabricación de paneles de GRC de forma libre. Se discutirán ventajas e inconvenientes de dichos métodos, sobre todo la importancia del molde y su repercusión económica. Finalmente se extraerán conclusiones sobre la viabilidad técnica y las posibilidades que se abren con este análisis

Optimización de la extracción acuosa enzimática del aceite de Oecopetalum mexicanum

En el presente trabajo se analizó la composición bromatológica de la semilla de cacaté (Oecopetalum mexicanum) y se optimizó el proceso de extracción acuoso enzimático del aceite. Los preparados enzimáticos Crystalzyme Cran y Cellulase fueron evaluados para determinar su influencia sobre los rendimientos de extracción del aceite de O. mexicanum. La parte experimental se desarrolló en dos etapas, en la primera se evaluó el efecto de las variables tipo de enzima, concentración de enzima, tamaño de partícula y tiempo de incubación mediante un diseño experimental L8 tipo Taguchi, la segunda etapa consistió en optimizar aquellas variables que influyeron sobre el rendimiento de aceite, a través de un diseño Box-Benhken. Los resultados del análisis bromatológico muestran que la semilla de cacaté contiene 39.25±0.33% de aceite. Un incremento en la extracción de aceite fue observado usando el preparado enzimático Crystalzyme Cran a 50°C, con una relación sólido: líquido de 1:5. Las condiciones óptimas para la extracción del aceite de O. mexicanum obtenidas mediante el diseño experimental Box-Benhken fueron velocidad de agitación de 89 rpm, concentración de enzima de 0.5% y tamaño de partícula 0.595 mm con un porcentaje de rendimiento de 150

Development of a dispersive liquid-liquid microextraction coupled with magnetic dispersive microsolid phase extraction for determination of triazines in wastewater samples

Producción CientíficaThe combination of two microextraction techniques (dispersive liquid-liquid microextraction [DLLME] and magnetic dispersivemicrosolid phase extraction [MDMSPE]) was developed and reported for atrazine and simazine preconcentration from wastewatersamples. The proposal methodology involved the use of magnetite supports functionalized with different alkyl or phenyl groups. Themagnetic adsorbents were synthesized by the solvothermal methodassisted by microwave, characterized, and used in the samplepreconcentration of atrazine and simazine. The method validation included parameters such as the wastewater matrix effect, repeat-ability, and recovery. The analyte separation and quantification were performed by high-performance liquid chromatography withultraviolet detection (HPLC-DAD). Parameters, such as the polarity and mass of magnetic solids and pH, were evaluated to providebetter extraction performance. The highest recoveries (> 95%) were obtained with 50 mg of the phenyl group support (CS2) at pH 5,using 5 mL of the sample and carbon tetrachloride and methanol, as extraction and dispersive solvents, respectively. The lowest limitsof detection (LOD) achieved were 13.16 and 13.86 ng L−1, and the limits of quantification (LOQ) were 43.89 and 46.19 ng L−1forsimazine and atrazine, respectively, with repeatability (expressed as %RSD) below 5% in all cases. The developed method is simple,easy, and low cost for the analysis of two herbicides potentially dangerous for environmental and human health

An In Silico Approach to Enzymatic Synthesis of Fucooligosaccharides Using α-L-Fucosidase from Thermotoga maritima

Abstract: Fucooligosaccharides comprise the primary group of human milk oligosaccharides. Due to their beneficial properties, a series of synthetic methods have been proposed to obtain them. Enzy- matic methods show great promise, and α-L-fucosidase from Thermotoga maritima has emerged as a powerful catalyst for their production. Nonetheless, the enzyme’s limited substrate scope has de- layed its wider application. The present work aims to compare the relative reactivity of fucose, pNP-fucose, and ethyl-fucose, while also exploring the molecular interactions of these fucosyl-donors with the enzyme through a combination DFT and docking analysis. The HOMO-LUMO band gaps range from −7.14571 to −4.24429 eV, with α/β-pNP-fucose and α-fucose being the three most reactive compounds. Moderate association energies between −6.4 to −5.5 kcal·mol−1 were found in the dock- ing analysis, with α-pNP-fucose and both anomers of ethyl-fucose demonstrating the poorest affinity. In the case of α/β-lactose affinity to the β-fucose/enzyme complex, no significant differ- ences were shown. We conclude that the best fucosyl-donors for transfucosylation are those that maintain an enzyme affinity and reactivity similar to pNP-fucose

Desarrollo de una metodología voltamperométrica para la determinación de Aflatoxina B1 usando un electrodo de carbón vítreo modificado con una película de bismuto y nanopartículas de oro

La Aflatoxina B1 es una micotoxina altamente cancerígena que se encuentra en una gran variedad de alimentos y piensos, por lo tanto, su cuantificación es importante para la industria de los alimentos. En este trabajo de investigación se describe el desarrollo de una metodología electroanalítica utilizando un electrodo de carbón vítreo modificado superficialmente con una película de bismuto y nanopartículas de oro para la cuantificación de Aflatoxina B1, por las ventajas que presenta frente a otras metodologías que ya se han estudiado y validado para la cuantificación de esta sustancia. Los límites de detección y de cuantificación que se obtuvieron después de la de la optimización de la Voltamperometría de Onda Cuadrada mediante un diseño Box-Behnken fueron 11.19 y 37.31 ng L-¹, respectivamente. Estos parámetros nos indican que es posible cuantificar la aflatoxina B1 en un intervalo de concentraciones a nivel traza, tal como se encuentra en alimentos.feeds, therefore, its quantification is important for the food industry. This research paper describes the development of an electroanalytical methodology using a glassy carbon electrode modified with a bismuth film and gold nanoparticles for quantification of Aflatoxin B1, due to the advantages it presents over other methodologies that have already been studied and validated for the quantification of this substance. The detection and quantification limits obtained after optimization of Square Wave Voltammetry using a Box-Behnken design were 11.19 and 37.31 ng L-¹, respectively. These parameters indicated that it is possible to quantify the Aflatoxin B1 in a wide concentration range at trace levels, as expected in food

Effect of enological tannin addition on astringency subqualities and phenolic content of red wines

Four Italian red wine varieties (Sangiovese, Montepulciano, Barbera, Nero d'Avola) were used to investigate the effect of enological tannins on astringency characteristics and phenolic content of red wines. Wines were treated with three tannins of different origins (G = grape, E= oak, and P = exotic wood) at two concentrations (10, 20 g/hl) and aged for 1 year. Wines were evaluated for astringency and for 16 subqualities using check-all-that-apply questions. In addition, polymeric pigments, tannins, flavans, total anthocyanins, and color parameters were analyzed. Enological tannin promoted color stability by pigmented polymers formation. Astringency intensity was not enhanced, even better an improvement of mouthfeel sensations was achieved with wood-derived tannins. Multivariate analysis revealed a great influence of the variety on astringency and phenolic characteristics of wines. Therefore, the initial phenolic composition of wine seems to be the main driver of the evolution of wine during aging. Practical applications: Tannin addition is an enological practice widely widespread because of many economical benefits. The use of enological tannins during aging can contribute to color stabilization and to an improvement of astringency subqualities of wines. Training on astringency subqualities with touch standards coupled with the check-all-that-apply questions can provide an interesting way to reveal the different aspects of red wine astringency. Despite high astringency and high phenolic content, a wine may present desirable subqualities which can improve wine experience. Finally, a tailored use of enological tannins depends on wine variety

Evaluation of Antioxidant and Antiproliferative Properties of Three Actinidia (Actinidia kolomikta, Actinidia arguta, Actinidia chinensis) Extracts in Vitro

The total phenolic content, total flavonoid content, vitamin C content, and antioxidant activities of ethanol extracts from different kiwifruit varieties (Actinidia kolomikta, Actinidia arguta, Actinidia chinensis) were determined in this study. Multiple scavenging activity assays including the hydroxyl radical, O2−·radical, DPPH, and the ABTS+ radical scavenging activity assays were used to identify the antioxidant activities of Actinidia extracts. The cell viability of HepG2 and HT-29 cells was also examined in this study. The results demonstrated that the Actinidia kolomikta extract had a higher antioxidant activity than the other two Actinidia extracts. There is a positive correlation between antioxidant activity and the polyphenols and vitamin C content in all three extracts (R2 ≥ 0.712, p < 0.05). The Actinidia arguta extract had the highest inhibitory effect on HepG2 and HT-29 cell growth. These results provide new insight into the health functions of fruit and demonstrate that Actinidia extracts can potentially have health benefits