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Copyright of Journal of Innovative Engineering / Revista de Ingenieria Innovativa is the property of ECORFAN-Mexico S.C. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this work, different microwave reaction times (0, 10, 20, and 30 min) have been evaluated to obtain an alkyl polyglucoside from Sacha inchi (Plukenetia volubilis L.) and glucose using microwaves at a power of 200 W and a temperature of 70 °C. The characterizations of the respective results were performed by Fourier Transformed Infrared Spectroscopy (FTIR) which allowed showing the progress of the reaction. Residual glucose quantification was achieved using the colorimetric method of spectrometry through a reaction with Antrona. The yield of the reaction was equal to 42.8%. This study constitutes an important precedent for the development of surfactants under mild reaction conditions. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the effect of five cooking methods (steam, grill, oven, frying and microwave) on farm-raised rainbow trout's sensory acceptability, physicochemical characteristics, and nutritional value. A survey was conducted with 307 consumers to create a marinade made with salt, garlic, cumin and pepper. The fillets marinated in this mixture were cooked, and photographs were taken to determine their sensory profile using the Check All That Apply (CATA) method, as well as their appearance through both visual (n = 289) and virtual (n = 100) surveys. Similarity was found between the sensory attribute maps for frying, oven and grilling in both evaluation methods. Significant differences (p < 0.05) in proximal composition were observed between the cooking techniques studied because of their technological parameters. The methods with the best visual acceptability were frying and microwave, and they caused an increase in the peroxide index. The n-6/n-3 ratio for both techniques (3.62 and 2.05) was within the requirement, being higher in frying due to the predominance of Omega 6 fatty acids incorporated by the oil used. This study demonstrated that the Peruvian consumer prefers cooking techniques characterized by ease of preparation and marked the development of color and texture attributes. [ABSTRACT FROM AUTHOR]

This study aimed to assess the effectiveness of two clarifying procedures and their effects on some properties in thermally or microwave-pasteurized pomegranate juices. The experiment consisted in combining pectinase and protease as well as chitosan and gelatin once they were being stored in the refrigerator. The experiment consisted in three parts, being the first one a fresh juice without any clarification treatment, whereas, the second one was the fresh juice treated with clarifying agent consisted of pectinase and protease mixture ratio (2:1) at 0.75 v/v,and 50 °C for 20 min. Finally, the third one was fresh juice treated with chitosan and gelatin mixture at 0.4 and 0.8) g/L, respectively, at 50 °C for (20) min. The pasteurization of all three experiments was done by using two techniques, i.e., one with thermal water bath at 85 °C for two min and the microwave at 400 Watts for two min. All pomegranate juice bottles were stored at 4 °C for three months. The results showed a significant effect of the clarification method variable on the properties studied, especially turbidity, polyphenol and anthocyanin values. Moreover, the juice clarified with the enzymatic clarification method had better characteristics than the traditional ones during storage, what has therefore a better commercial appeal. The area of significance was founded with the use of traditional clarification with concentration at (0.4 and 0.8) g/l, and microwave pasteurization with 400 watts and zero month of storage at 4 °C, respectively, which is provided a minimum turbidity value. [ABSTRACT FROM AUTHOR]

Copyright of Revista de la Sociedad Química del Perú is the property of Sociedad Quimica del Peru and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

En este trabajo se han evaluado diferentes tiempos de reacción de microondas (0, 10, 20 y 30 min) para obtener un alquil poliglucósido de Sacha inchi (Plukenetia volubilis L.) y glucosa utilizando microondas a una potencia de 200 W y una temperatura de 70 °C. Las caracterizaciones de los respectivos resultados se realizaron por Espectroscopia Infrarroja Transformada de Fourier (FTIR) lo que permitió evidenciar el avance de la reacción. La cuantificación de glucosa residual se logró mediante el método colorimétrico de espectrometría mediante reacción con Antrona. El rendimiento de la reacción fue igual al 42.8%. Este estudio constituye un precedente importante para el desarrollo de tensoactivos en condiciones de reacción suaves.

El objetivo de este estudio fue evaluar el efecto de cinco métodos de cocción (vapor, plancha, horno, microondas, fritado) en las características fisicoquímicas, valor nutricional y aceptabilidad sensorial de trucha arcoiris (Oncorhynchus mykiss) de origen piscícola. Se aplicó una encuesta a 307 consumidores para definir la formulación de la solución de adobado constituida por sal, ajos, comino y pimienta. Los filetes marinados en esta solución fueron cocinados por cada método y se registraron fotografías para la determinación de los perfiles sensoriales mediante el método CATA (Check All That Apply), así como la aceptabilidad de la apariencia mediante la evaluación virtual (n = 289) y presencial (n = 100). En ambas modalidades se encontró una similitud entre los mapas de atributos sensoriales para el fritado, horneado y a la plancha. Se evidenciaron diferencias significativas (p < 0,05) en la composición proximal entre las técnicas estudiadas como consecuencia de los parámetros tecnológicos de cocción. El fritado y microondas obtuvieron la mayor aceptabilidad en apariencia y ocasionaron un incremento del índice de peróxido. La relación n-6/n-3 para ambas técnicas (3,62 y 2,05) se ubicó dentro del requerimiento, siendo mayor en la fritura debido al predominio de ácidos grasos Omega 6 incorporados por el aceite empleado. La elección de estos dos métodos demuestra que el consumidor peruano aprueba técnicas caracterizadas por la facilidad de preparación y un marcado desarrollo de atributos de color y textura.

The effect of microwave roasting process on the compositional parameters and bioactive contents of fig seed oil were investigated. Fig seeds were ground and roasted in a microwave oven at 350, 460 and 600 Watt for 5 and 10 minutes and the roasted seeds were processed to obtain oil. The results showed that peroxide, K232 and K270 values were adversely affected by roasting. Fig seed oil was a prosperous source of γ-tocopherol and significant losses were observed due to microwave pre-treatment. The major fatty acids in fig seed oil were linolenic, linoleic and oleic acids; whereas the major triacylglycerols were LnLO, LnLnL, LnLnLn and LnLnO, according to fatty acid profile. The most abundant sterol in the fig seed oil samples was β-sitosterol with 3235.90 to 3625.62 mg/kg, followed by Δ5-and Δ7-avenasterols. The principal component analysis and agglomerative hierarchial clustering served to differentiate between intense and mild microwave-treated oils as well as the unroasted samples. [ABSTRACT FROM AUTHOR]

Hydroxyapatite is the main bones and teeth inorganic mineral component. This material has been an object of research aiming its use in biomaterials as bone replacement option for biomedical applications. In this investigation, the synthesis of hydroxyapatite was studied by the Hydrothermal (HT) and Microwave Irradiation (MW) methods. Here, parameters such as pH (9 and 11) and synthesis time were varied, and residue of chicken eggshell was used as calcium precursor. The obtained powders were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Dispersive Energy X-ray Spectroscopy (EDS), and Transmission Electron Microscopy (TEM). The results showed that the material synthesized when the pH reached the value of 9 which generated less carbonated powders than those with pH of 11. The Hydrothermal method presented more satisfactory morphological results according to the TEM analysis. This procedure was considered more suitable as a route to obtain hydroxyapatite as biomaterial. Resumen: La hidroxiapatita es el principal componente mineral inorgánico de huesos y dientes. Este material ha sido objeto de investigación dirigida a su uso en biomateriales como sustituto óseo en aplicaciones biomédicas. En este trabajo, se estudió la síntesis de hidroxiapatita utilizando los métodos hidrotermal (HT) y de irradiación de microondas (MW), variando parámetros como el pH (9 y 11) y el tiempo de síntesis, utilizando como precursor de calcio, el residuo de la cáscara de huevo de gallina. Los sólidos (polvo) obtenidos se caracterizaron por difracción de rayos X (DRX), espectroscopía infrarroja por transformada de Fourier (FTIR), espectroscopía de energía dispersiva (EDS) y microscopía electrónica de transmisión (MET). Los resultados mostraron que el material sintetizado a pH 9 generó polvos menos carbonatados que aquellos obtenidos a pH 11. El método hidrotérmico presentó resultados morfológicos más satisfactorios según el análisis de MET. Este procedimiento se consideró más adecuado como una ruta para obtener hidroxiapatita como biomaterial.

The present research examines the impact of microwave of (230-240V-50Hz 900W) on the viability of Echinococcus granulosus protoscoleces in vitro for different exposing periods, 3, 5, 7, 10, 12, 13, and 15 seconds, respectively. Subsequently, the study investigates the prevention of mice against infestation with secondary hydatid cysts, compared with the control animals infested with protoscoleces without exposure to microwaves over four months, depending on many criteria, including the numbers, weights, and diameters of developed hydatid cysts. The results revealed an obvious infl of microwaves on Echinococcus granulosus protoscoleces viability by an increase of exposure period in vitro, 90%, 80%, 77%, 70%, 50, 30, and 0%, respectively. Plus, the results showed a decrease of 97%, 92.5% of hydatid cysts numbers in the mice injected with exposed protoscoleces with 30% fertility exposed for 13 seconds, four months post-infection, followed by 92.5% and 87.2% in the same group, two and three months post-infection. [ABSTRACT FROM AUTHOR]

La agroindustria genera gran cantidad de residuos de tipo orgánico, los cuales son considerados una biomasa apta para aprovechamiento energético. Una de las tecnologías de conversión termoquímica que permite obtener un producto de alto valor energético es la carbonización hidrotermal, la cual puede ser asistida por microondas o por horno convencional. El objetivo de este artículo fue recopilar información sobre la influencia que tienen los parámetros operativos en la obtención de mayores rendimientos y contenidos de carbono del hidrochar en el proceso de carbonización hidrotermal asistida por microondas (MAHTC) y, a su vez, demostrar tal influencia de los parámetros mediante un metaanálisis. Para el metaanálisis se tomó la información bibliográfica recopilada y se evaluó a través de un modelo lineal generalizado tipo mixto. Los resultados del modelo evidenciaron que la temperatura y el tiempo ejercen influencia en el contenido de carbono, mientras que el rendimiento estaría influenciado, principalmente, por el tiempo de reacción. En términos generales, se resalta al parámetro de la temperatura de reacción como el factor más importante en la carbonización hidrotermal, ya que determina las propiedades fisicoquímicas del hidrochar, es decir que con la información aquí presentada se pretende incentivar el aprovechamiento de los residuos agroindustriales para ser transformados en productos de alto valor energético y, de este modo, brindar una solución a la problemática de cambio climático, propiciando el desarrollo sostenible del sector agrícola.

Bioactive compounds of interest are available in various parts of plants; its extraction and stability are important in the preparation of functional foods. In this work, the antioxidant characteristics of the aqueous extracts from Moringa oleifera leaves were evaluated. Various extraction methods. hot, enzymatic, with ultrasound and microwaves were evaluated in order to select the most convenient method to prepare a drink. Furthermore, the antioxidant stability of the drink was evaluated for 28 days at 10, 25 and 35 °C. It was determined that the most suitable method was hot extraction at 85 °C with a concentration of 0,5 % of moringa leaves. The drink showed a retention percentage of 90 %, 91% and 84 % in total phenols, CA Cuprac and % DPPH * inhibition at 25 ° C with respect to its initial content and a half-life time of 6,4 months in the content of total phenols. In the evaluated period, the drink showed acceptable sensory characteristics. [ABSTRACT FROM AUTHOR]

In this study, the effects of a moderate electrical field application and two different blanching methods (conventional and ultrasound) on the frying (deep-frying in oil at 180 °C for 6 minutes and compared to the microwave (400W)) of zucchini slices were investigated. Microwave-fried samples presented a lower moisture content than deep fried ones. The moderate electrical field signifi- cantly reduced the oil content before the microwave frying. Greenness (--a*), which is important for the zucchini samples, was found at its best (-3.25) in the combination group of moderate electrical field pre-treated, ultrasound blanched, and microwave fried. Gumminess, cohesiveness, and fracturability of the zucchini slices decreased while chewiness, springiness, and resilience increased after microwave frying. The scores of the sensory test were higher for the ultrasonic blanching and microwave fried sample groups. Besides, these electrical methods were found more advantageous in terms of energy consumption. [ABSTRACT FROM AUTHOR]

Zingiber officinale (ginger) belongs to the Zingiberaceae family. It is a species widely used as a home remedy to aid digestion, treat flu, cough, nausea, and other ailments. Its aroma and flavor comes mainly from its essential oil, which has properties as an anti-inflammatory and antioxidant agent. The objective of this research is to extract the essential oil of ginger collected in the department of Quindío, using the hydrodistillation technique coupled to Clevenger and assisted by microwaves with and without previous ultrasound treatment. Determine its physicochemical properties such as relative density, refractive index and its organoleptic properties; additionally, to compare the metabolic content of essential oils obtained by gas chromatography coupled to mass spectrometry. [ABSTRACT FROM AUTHOR]

Elettaria cardamomum (Cardamom) is a species belonging to the Zingiberales order and the Zingiberaceae family. It is used in the preparation of food; it has intensely aromatic seeds and an excellent content of essential oils, is considered the queen of spices. Among the applications of its essential oil, the main characteristic to highlight are the antioxidant properties, the essential oil of cardamom is used in the gastronomic industry; in addition, medicinal properties are attributed. The objective of this research is to extract the essential oil from the seeds of Elettaria cardamomum by means of hydrodistillation coupled to Clevenger and assisted by microwaves, with and without previous ultrasound treatment and analyzing the metabolic content of the oils obtained by gas chromatography coupled to mass spectrometry. [ABSTRACT FROM AUTHOR]

The factors affecting the microwave bleaching of sunflower oil and the interaction between them were investigated and optimized by response surface methodology using a three-factor five-level central composite rotatable design. Microwave power, time and the amount of bleaching clay were selected as independent variables studied in the range of 70-120 W, 2-15 min, and 0.01-0.5%. The dependent variables that measure the bleaching efficiency and oil quality were evaluated as hue angle, chroma and totox value. Optimization was carried out by minimizing totox and chroma and maximizing hue angle. Hue angle, chroma and totox were found as 96.91, 37.66 and 23.31 under optimal conditions. Optimal microwave bleaching was successfully performed by using less bleaching clay (0.4%) and a shorter time (8 min) compared to the current industrial application without any adverse effect on oil quality. Hence, microwave bleaching is thought to be an alternative method for the bleaching of edible oils. [ABSTRACT FROM AUTHOR]

The (Zingiber officinale) is a plant of the zingiberáceas family, its rhizome is widely used in gastronomy for its pungent aroma and flavor. Essential oils (EO) are natural compounds; they have 25 to 70 components with different concentrations. Α-Zingiberene and α-Felandrene are the main components with volumes between 20% and 70%. For the extraction of the AE samples from 10 Colombian geographical locations were used, obtained by microwave radiated hydrodistillation (MWHD) and stored at 4°C in amber vials. 50 µL of EA and 1.0 µL of (n-tetradecane) internal standard were dissolved in dichloromethane to a final volume of 1.0 mL. The EO components were performed on a triple quadruple mass detector gas chromatograph (BRUKER 450GC-320). For its antioxidant activity (AA) the methodology of Prior for DPPH* and ABTS+ was used. The extractions showed a yield between 0.053 and 0.109 percent; and 300 g of sample at 700 watts and 40 minutes of process were used. The chromatographic profile showed 43 components referring to ketones, alcohols, cyclic ethers, aldehydes and 23 hydrocarbons, with α-Zingiberene being the majority, considered as a molecular marker of this EO. The AA presents significant differences between the samples evaluated for the localities studied.

The aim of this study was to model the drying kinetics of microwave and fluidised bed of parchment coffee beans (Coffea arabica L.) using a semi-theoretical approach. A completely randomized design with six treatments: three with microwave drying (MD) and the rest with microwave fluidised bed drying (MFBD) was carried out. The drying curves were established until reaching a final moisture content between 10 and 12 % w.b. Results indicated that the drying time decreased as the microwave power level increased. When MFBD was used, drying times increased approximately 4-fold compared to MD treatments. The values of effective diffusivity for coffee beans treated with MD and MFBD ranged from 0.913 to1.72x10-9 m².s-1 and from 0.23 to 0.42x10-9 m².s-1, respectively. Although all the models presented high goodness of fit, the two-term model presented the highest R² (>0.98) and lowest RMSE (0.0128-0.0285). In general, all models adequately fit the experimental data, so they can be used to predict the drying kinetics, therefore they could be very useful in equipment design and optimization of the coffee drying process. [ABSTRACT FROM AUTHOR]

Este artículo presenta una técnica para mejorar el proceso de diseño industrial de transistores de microondas, basado en un diseño de experimentos mejorado (DOE) y un modelado electrotérmico (MET) expandido. El diseño de experimentos DOE permitió centrar el diseño a través de variaciones en parámetros específicos, para evitar complejas simulaciones electromagnéticas de acoplamiento mutuo entre los cables dentro del mismo transistor, que generalmente en herramientas CAD convencionales presentan un elevado costo computacional. El modelo electrotérmico mejorado utilizando la técnica de voltajes efectivos posibilitó predecir no solo el autocalentamiento, sino también las impedancias apropiadas para la máxima potencia de salida y la máxima eficiencia del transistor. De esta manera fue posible elegir las condiciones de operación que garantizaran un reducido autocalentamiento, así como las mejores condiciones de potencia, eficiencia y linealidad. Las técnicas presentadas son útiles para la implementación de amplificadores de potencia en los futuros sistemas de comunicación inalámbricos, ya que deben trabajar con potencias elevadas que producen autocalentamiento y con señales de gran ancho de banda. La combinación de ambas técnicas permite la reducción de diseño y tiempo de producción en el ámbito industrial. El diseño de experimento mejorado posibilitó centrar el diseño del transistor para asegurar la obtención de los mejores desempeños del transistor. La caracterización térmica facilitó que el transistor de microondas, implementado en un circuito impreso de potencia, funcionara por debajo de la temperatura máxima permitida, lo que garantiza su vida útil y, en consecuencia, la confiabilidad del sistema de transmisión completo.

En el presente trabajo se ha presentado un análisis de transistores de efecto de campo usando fuentes de voltaje pulsadas. Se han realizado medidas de microondas en dispositivos de tecnología HEMT’s y LDMOS poniendo en evidencia la diferencia entre el comportamiento estático y dinámico de dichos dispositivos. En base a las medidas se ha realizado un procesamiento de datos derivando una nueva ecuación con la capacidad de reproducir ambos tipos de comportamiento con elevada precisión y en diferentes puntos de operación. Consecuentemente el trabajo aporta un nuevo modelo basado en un circuito no lineal de cuatro terminales. La relevancia de este modelo es la capacidad de predecir los efectos físicos como la dispersión frecuencial y la movilidad electrónica del dispositivo semiconductor. Esto es importante pues la dispersión frecuencial es uno de los problemas más importantes de los sistemas de comunicación modernos que genera efectos memoria limitando la capacidad de transmitir señales de gran ancho de banda. El hecho de poder predecir la movilidad electrónica y la dispersión frecuencial ayudan al diseñador de circuitos a mejorar su calidad y tiempo de diseño. Además, permite a la industria de fabricación de componentes de RF ahorrar costos de producción pues esta técnica permite predecir el comportamiento de los circuitos antes de implementarlos. La metodología para la obtención del modelo compacto ha sido validada a través de la implementación de un amplificador de potencia en tecnología LDMOS usando la técnica propuesta. El modelo propuesto es abierto puesto que la nueva técnica propuesta se puede implementar en cualquiera de los modelos convencionales usados actualmente en el ámbito industrial y académico.

La papaya es un cultivo de gran importancia a nivel mundial. México y Colombia son líderes mundiales en su producción; una de las principales limitantes para este cultivo son las enfermedades dentro de las que destaca la antracnosis que afecta en pre y poscosecha, es por ello que la investigación en la búsqueda de alternativas eficientes, sustentables e inocuas en la sanidad del cultivo son primordiales para reducir las pérdidas en la producción y con ello mejoren los ingresos y la calidad de vida del productor y los involucrados en la cadena productiva, hasta el consumidor, con productos de calidad y sin contaminantes que afecten su salud. El objetivo de este estudio fue evaluar extractos de plantas bajo dos formas de extracción en el control in vitro de Colletotrichum gloesporioides. Por lo que fue evaluado el efecto antifúngico de extractos vegetales de hojas de orégano (Oreganum vulgare), frutos de pimienta (Pimienta dioica), hojas de neem (Azadirachta indica.) y hojas secas de matarratón (Gliricidia sepium) obtenidos a partir de métodos de destilación y microondas, sobre C. gloesporioides aislado de Carica papaya. Fue utilizada la técnica de medio envenenado en cajas Petri con medio PDA; en una primera fase, se probó la concentración 60 % para todos los extractos. Posteriormente fue determinada la concentración mínima inhibitoria para aquellos que en la primera fase inhibieron el 100 %. El efecto antifúngico se determinó mediante crecimiento micelial, número de conidias totales y germinadas. Los resultados indicaron que el extracto de fruto de pimienta obtenido por microondas, en una concentración de 40% y el producto patente M2 UNACH en una concentración de 20 %, inhibieron totalmente a C. gloesporioides. los extractos obtenidos mediante el microondas tuvieron mejor efecto antifúngico que los obtenidos por destilación.

Sago starch is an underutilized starch due to its low functionality in food formulation. Modification is effective in improving starch functional properties. In this study, the starch were modified to enhance its functional properties. The starch was microwave-heated with different treatment durations of 5, 10, 15, or 20 min, separately, yielding microwave-heated starches (MHT1, MHT2, MHT3, and MHT4). The modified starches have irregular shaped granules and fissures while maintaining their mean diameters. The degree of double helix had increased, indicating more double helix structure of amylose formed. The modified starches' moisture content, solubility, and paste clarity were significantly decreased. The MHT4 had its swelling power and syneresis increase. In conclusion, the treatment duration influenced the physicochemical properties of the sago starch, which is related to the formation of amylose double helix structure. Further study should focus on the formation of double helix structure in starch and its impact towards food structure. [ABSTRACT FROM AUTHOR]

Grass pea (Lathyrus sativus L.) is an important food legume crop but notorious for plant neurotoxin β-N-Oxalyl-L-α, β-diaminopropionic acid (β-ODAP), causing neurolathyrism to human and animals. The study aimed to compare changes in physical and chemical parameters of 13 genotypes of different geographic origins in pre & post-boiling, microwaving and autoclaving. The results showed significantly different effects of pre and post-cooking treatments on genotypes and cooking methods independent of one another. The genotypes from South Asia exhibited higher β-ODAP content compared to the genotypes from other region. Significantly negative correlation was noted between protein content and β-ODAP concentration across the treatments under boiling (r = −0.555**) and microwave (r = −0.342*) treatments. Boiling was the best treatment and significantly reduced β-ODAP concentration by 70%. Its reduction percentage remained 30%, and 14% under microwaving and autoclaving, in the same order. Therefore, boiling was recommended over other treatments for safe human consumption of grass pea seeds. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the properties of clove essential oil extracted by different microwave-assisted methods and to evaluate its effects on the stability of common Kilka oil. Each of these methods was hypothesized to yield a clove essential oil that would have a distinguishable composition and effect when added to common Kilka oil by maintaining its oxidative stability. The oxidation of common Kilka oil was examined by accelerated oxidation using the active oxygen method and Rancimat test. The clove essential oil extracted by microwave-assisted hydrodistillation showed the highest induction period according to the active oxygen method (16.56 h) and the Rancimat induction period (3.64 h) in common Kilka oil and its antioxidant activity was comparable to that of BHT (16.59 h and 4.34 h, respectively) and tocopheryl acetate (16.30 h and 4.02 h, respectively). Furthermore, the microwaveassisted hydrodistillation method resulted in the amount of eugenol that exhibited the highest antioxidant capacity for preserving PUFA in common Kilka oil. Ultimately, clove essential oil can become an efficient natural antioxidant for the oxidative stability of common Kilka oil. [ABSTRACT FROM AUTHOR]

The present research study assessed the drying kinetics of non-extruded pellet feed for red tilapia (Oreochromis spp.). The pellets were made with conventional inputs in the control diet by using convective drying and microwave drying. Pellets were made with a control diet and with a diet including viscera silage for which the most relevant physical parameters were determined. The selection criterion was floatability. The results showed that the best method was microwave drying, which delivered pellets with physical properties, floatability (63-96%) and expansion ratio (1.6-1.8), similar to that of extruded pellets. However, pellets made with a silage diet required the application of waterproofing strategies to improve their stability in water. It is concluded that microwave dried red tilapia feed has similar physical properties to feed made by conventional methods. [ABSTRACT FROM AUTHOR]

El Stellarator de Costa Rica 1 (SCR-1) es un dispositivo pequeño de confinamiento magnético de tipo stellarator modular que se emplea para la investigación de plasmas de alta temperatura y baja densidad, el primero de América Latina. [1]. El propósito de este trabajo es diseñar un dispositivo capaz de medir experimentalmente, de forma precisa, la densidad electrónica del plasma. Es por esto que se pretende diseñar un interferómetro heterodino de microondas, uno de los primeros diagnostico experimentales que se utilizan para medir este parámetro, debido a su alta fiabilidad. [2] En este documento, se calcula la frecuencia optima de operación, junto con su respectivo desfase máximo. Además, se presenta un diagrama de bloques del sistema, que da hincapié a la especificación de cada uno de los componentes del diseño y a su vez sera soporte para realizar un balance de potencia y un análisis del comportamiento teórico de la señal a lo largo del sistema. Se concluyo que el sistema cumple con los requerimientos necesarios para su implementación.

Medir el contenido de humedad (CH) de los agregados de concreto (ADC) en la fabricación de concreto premezclado es uno de los retos actuales en la industria de la construcción porque afecta a las propiedades finales del concreto. Actualmente los métodos que se utilizan para medir el CH en ADC son invasivos y destructivos. Este artículo presenta una técnica moderna basada en espectroscopía dieléctrica (ED), un método que al propagar microondas en el material correlaciona su constante dieléctrica (CD) y su CH. En esta investigación se ha utilizado este método en ADC. Tres diferentes canteras peruanas de ADC (Moyobamba, Sol-Sol y Cerro Mocho) han sido utilizadas. Los resultados demuestran que el sensor a una frecuencia de 1.5 GHz es capaz de detectar el CH en ADC con una regresión lineal de R2 = 95 %. En conclusión, se puede utilizar la ED como un método de sensado no invasivo y en línea de CH en ADC para ser utilizado en la industria de la construcción.

La irradiación de microondas es una fuente de energía no convencional que viene siendo utilizada para un gran número de reacciones químicas, comprobando que éstas pueden ser aceleradas bajo condiciones de irradiación de microondas. Debido a que la reacción de transesterificación contiene tanto componentes polares como iónicos, el calentamiento con microondas se compara favorablemente con los métodos convencionales. En este trabajo se realizaron estudios de los efectos de la irradiación de microondas en la síntesis de biodiesel con aceite de algodón y metanol usando hidróxido de sodio como catalizador. Se ha comprobado mediante ensayos de laboratorio que utilizando las mismas condiciones que con el método convencional de calentamiento se pueden alcanzar los mismos rendimientos, incluso mayores, que utilizando la irradiación microonda como fuente de energía, con la ventaja de una considerable reducción del tiempo de reacción.

Copyright of Revista de la Sociedad Química del Perú is the property of Sociedad Quimica del Peru and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Sociedad Química del Perú is the property of Sociedad Quimica del Peru and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Investigaciones Agroindustriales is the property of Revista Colombiana de Investigaciones Agroindustriales del Centro Agropecuario Sena Buga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ingenius, Revista Ciencia y Tecnología is the property of Universidad Politecnica Salesiana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

La obesidad y la diabetes generada por el consumo excesivo de sacarosa, ha impulsado tendencias de consumo de productos con edulcorantes naturales de bajo poder calórico. Los glucósidos de estevia son una alternativa edulcorante que poseen un dulzor 200-400 veces superior al de la sacarosa y con nulo aporte calórico. Estos glucósidos han sido obtenidos con técnicas convencionales de extracción que generan altos consumos energéticos y un impacto ambiental negativo. Este trabajo identifica las técnicas de extracción verdes más empleadas para la obtención de glucósidos. Entre ellas, las microondas que generan un rápido calentamiento debido a campos eléctricos y magnéticos. El ultrasonido que incrementa el área de transferencia debido a la cavitación. Los disolventes en condiciones supercríticas que tienen una mejor capacidad de extracción, y las enzimas que favorecen la disponibilidad del analito al romper la celulosa. El ultrasonido presentó los rendimientos más altos con valores de 96,46 mg/g y 36,92 mg/g de extracto para esteviósido y Rebaudiósido-A, respectivamente. Algunas de las nuevas técnicas de extracción basadas en las altas presiones y temperaturas como la efectuada con disolventes acelerados (con rendimientos hasta de 63,20 mg/g de extracto, para esteviósido), son tecnologías amigables con el medio ambiente y con potencial uso industrial.

Copyright of Revista Facultad de Ingeniería - UPTC is the property of Universidad Pedagogica y Tecnologica de Colombia, Facultad de Ingenieria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Microencapsulation protects different bioactive compounds (anthocyanins) from environmental factors, increasing their half-life. In this study, the extraction and microencapsulation conditions for purple cabbage anthocyanins were determined, in addition to stability of the natural pigment obtained in a fermented milk beverage. Scalded was used for enzymatic inactivation in purple cabbage (Brassica oleracea L. ssp. Capitata f. Rubra) leaves, the extraction of bioactive compounds was carried out using green technologies (microwaves), concentrating the anthocyanin solution and mixing with wall materials such as maltodextrin, inulin and gum arabic for microencapsulation and addition to fermented milk beverage. The color stability was determined for 8 days; the ΔE of the beverage was slightly perceptible by the human eye. The concentration of anthocyanins was 199 mg/L with a solution of water and 2% acidified ethyl alcohol at 880 W of power for 90 s; the best drying performance was 58.9%. [ABSTRACT FROM AUTHOR]

Copyright of Revista Facultad de Ingeniería - UPTC is the property of Universidad Pedagogica y Tecnologica de Colombia, Facultad de Ingenieria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To evaluate the influence of different cooking methods on the sensory characteristics of restructured beef rolls was the objective of the work. For experiments, 20 kg temples were prepared the meats were ground by a pre-cutter disk with three holes in the shape of a kidney and a two-armed blade. They were prepared using sodium tripolyphosphate, common salt, sodium ascorbate, and the mixture sodium alginatecalcium carbonate-sodium ascorbate, citric acid, isolated from soy and spices, which were combined to obtain six variants. The cooking was by frying, with steam, in a microwave oven and in dry heat, and the sensory evaluation was carried out taking into account the attributes of appearance, taste, color, texture, juiciness and cohesiveness, by means of an appropriate scale. The best variants in all sensory attributes studied turned out to be those treated thermally by the frying method, in addition to affecting all the sensory characteristics of the variants, especially juiciness and tenderness. When cooking in a microwave oven, all the variants showed affectation in the evaluated attributes. [ABSTRACT FROM AUTHOR]

Generated by the overconsumption of sucrose, diabetes and obesity has led to consumption trends of products with low calorie natural sweeteners. Glycosides of Stevia are an alternative sweetener that has a sweetness 200-400 times greater than sucrose and also have zero calorie. These glycosides have been obtained with conventional extraction techniques that generate high energy consumption and negative environmental impact. This work identifies the most used green extraction techniques for obtaining the glycosides. Some of them like microwaves generate rapid heating due to electric and magnetic fields; ultrasound increases the area of mass transfer due to cavitation, solvents in supercritical conditions have better ability to extraction, and enzymes promote the availability of the analyte breaking the cellulose. Ultrasound presented higher yields with values of 96,46 and 36,92 (mg/g of extract) for stevioside and Rebaudioside-A, respectively. Some of the new extraction techniques based on high pressures and temperatures like the use of accelerated solvents extraction (with yields of up to 63,20 mg/g dry extract, for stevioside), are environmentally friendly technologies with the environment and they have potential industrial uses. [ABSTRACT FROM AUTHOR]

Copyright of @limentech: Ciencia y Tecnología Alimentaria is the property of Journal @limentech, University of Pamplona and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Investigaciones Agroindustriales is the property of Revista Colombiana de Investigaciones Agroindustriales del Centro Agropecuario Sena Buga and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bioactive compounds are extracted from natural sources and they have beneficial effects on human health. Fruits and vegetables are rich in carotenoids, phenolic compounds, Vitamin C, among others. Extraction processes for these compounds depend on several factors such as the technique that is used, the raw material, and the organic solvent. Conventional techniques generally require large amounts of organic solvents, high energy expenditure, and are time consuming, which has generated interest in new technologies that are referred to as clean or green technologies. These can reduce or eliminate the use of toxic solvents, and thus preserve the natural environment and its resources. The aim of this review is to discuss recent techniques used to extract bioactive compounds from natural sources, in order to reduce the economic and ecological impact of these processes. [ABSTRACT FROM AUTHOR]

Antecedentes: la cocción de alimentos en horno microondas es una tendencia en aumento en la población en general, sin que se tenga en cuenta el efecto sobre su calidad. Objetivo: evaluar el efecto del extracto de Bixa orellana sobre aceite de girasol durante el calentamiento en microondas. Materiales y métodos: aceite de girasol, con y sin la adición de extracto de Bixa orellana 100 ppm, se sometió a calentamiento durante 12 minutos en horno microondas evaluándose sus propiedades fisicoquímicas a distintos intervalos de tiempo. Resultados: la adición de Bixa orellana contribuye a conservar la calidad del aceite de girasol sometido al microondas durante los tres primeros minutos de calentamiento. A tiempos mayores, dadas las temperaturas alcanzadas, no se observa efecto protector. Conclusión: la adición de 100 ppm de extracto de Bixa orellana en aceite de girasol permite contrarrestar la oxidación durante tres minutos de calentamiento en microondas.