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Copyright of Environmental & Social Management Journal / Revista de Gestão Social e Ambiental is the property of Environmental & Social Management Journal 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.)

Introducción. En los últimos años se han buscado opciones de desinfección para los vegetales frescos y mínimamente procesados. Alternativas como el uso de ácidos orgánicos, pueden reducir microorganismos en los alimentos. Objetivo. Evaluar el uso de ácido cítrico y láctico en diferentes concentraciones para la reducción microbiológica de Escherichia coli y Listeria monocytogenes en repollo y zanahoria rallados. Materiales y métodos. El trabajo se realizó en San José, Costa Rica, durante los meses de setiembre a noviembre de 2023. Se ralló repollo y zanahoria, se inocularon con E. coli y L. monocytogenes y se desinfectaron con ácido láctico y cítrico a concentraciones de 5, 10 y 20 g l-1 durante 5 min. Se determinó la reducción logarítmica posterior a la desinfección y se evaluó con contrastes ortogonales y pruebas de Bonferroni la contribución de los ácidos a la reducción con respecto al control en agua, así como diferencias en las reducciones entre ambos ácidos y el efecto de la concentración. Resultados. Se determinaron en zanahoria y repollo reducciones de E. coli entre 2 y 5 log UFC/g. Las mayores reducciones en general se observaron a 20 g l-1 en comparación con 5 g l-1, para el ácido láctico en comparación con el cítrico. La determinación en zanahoria para L. monocytogenes no fue posible, sin embargo, en repollo se obtuvieron valores entre 1,2 y 2,4 log UFC/g con las mayores reducciones a 20 g l-1 en comparación con 5 g l-1 y para el ácido láctico en comparación con el cítrico. Conclusiones. En las condiciones estudiadas de concentración y tiempo fue posible utilizar ácido láctico y ácido cítrico para implementar procesos de desinfección de repollo y zanahoria rallados y lograr reducciones de al menos 2 log UFC/g.

Hydrogels were prepared from methyl methacrylate, glycerol, and sulfuric or citric acid. A novel route for the synthesis of crosslinked materials using unconventional initiators was evaluated using a 23 factorial experimental design. Effects of independent variables (polymerization time, type, and acid concentration) were statistically analyzed through ANOVA. The synthesis route includes condensation, free-radical and transesterification reactions with modifications of the polymer chemical properties such as the formation of a crosslinking polyester with polymethylmethacrylate (PMMA) and improvement of the mechanical and thermal properties of the hydrogel. A polymerization time of 4-hour produced the highest amount of material when 1.37 g sulfuric acid was used and 3.46 g when citric acid was added. The polymer synthesized with citric acid has a swelling rate up to 214.6%, compared with the materials produced with sulfuric acid that reach up to 31.3% of water absorption. [ABSTRACT FROM AUTHOR]

In this work, the adsorption of amoxicillin on unmodified, propylamine-modified, and citric acid-modified cassava peels was studied at laboratory scale. Adsorption tests were carried out at amoxicillin initial concentrations of 100 and 300 mg/l at pH values of 5, 6, 7, and 8, for each of the obtained adsorbents. The adsorption capacity results showed that the best pH of operation is 8 with a time of equilibria of 420 min. The kinetic data were fitted to the pseudo-first and pseudo-second order models obtaining better results with the last one and values for K2 of 2,13 g/mmol·min for unmodified cassava peels, 1,74 g/mmol·min for citric acid-modified cassava peels and 1,52 g/mmol·min for propylamine-modified cassava peels, respectively. The maximum removal percentage and maximum adsorption capacity were 34,4% and 0,016 mmol/g, for unmodified cassava peels; 50,39% and 0,024 mmol/g, for citric acid-modified cassava peels; and 50,93% and 0,024 mmol/g, for propylamine-modified cassava peels, respectively. [ABSTRACT FROM AUTHOR]

Copyright of GeSec: Revista de Gestao e Secretariado is the property of Sindicato das Secretarias e Secretarios do Estado de Sao Paulo (SINSESP) 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.)

Botrytis cinérea Pers. (B.C.) es el fitopatógeno responsable de una amplia gama de síntomas en cultivos de gran importancia como el tomate. Su control principalmente se basa en la aplicación de fungicidas químicos; sin embargo, su uso excesivo conduce al desarrollo de cepas resistentes, contaminación ambiental y efectos perjudiciales para la salud humana. Por ello, el objetivo el estudio fue evaluar el efecto de dos fertilizantes foliares que contienen cobre, zinc y ácido cítrico en el control del moho gris B.C. en tomate cv. Huascarán. En condiciones de laboratorio se evaluó el efecto de los fertilizantes foliares en la inhibición del crecimiento micelial a los 6 DDI (días después de inoculación) con el método del medio envenenado en PDA (agar de papa y dextrosa); y en condiciones de campo se aplicaron los fertilizantes foliares por ocho semanas variando la frecuencia de aplicación en una y dos semanas. Los resultados mostraron que en condiciones de laboratorio el ácido cítrico incrementó la actividad antifúngica complementándose bien con las partículas de Cu y Zn presentando el T3 el mejor porcentaje de inhibición del crecimiento micelial. En condiciones de campo la mayoría de las aplicaciones tuvieron un control significativo de B.C. en el follaje, pero no en flores ni en frutos; destacando aquellos donde se aplicó los fertilizantes foliares semanalmente. Estos resultados son importantes para desarrollar estrategias dirigidas a mejorar el control de la enfermedad y disminuir el uso masivo de fungicidas.

Introducción: las bebidas energizantes son muy consumidas en la actualidad debido a su capacidad para aumentar la resistencia, el rendimiento y energía para realizar las actividades diarias, se asocia con la salud oral debido a su alta capacidad de causar erosiones, hipersensibilidad y caries dental por sus componentes como la cafeína y el ácido cítrico. Objetivo: describir la asociación entre las bebidas energéticas y las enfermedades en la cavidad oral. Método: mediante el enfoque de investigación realizada en este artículo por medio de revisiones bibliográficas utilizando las bases de datos Pubmed, Scielo, Dialnet, Google Académico sin límite de años con el fin de obtener estudios acerca de las bebidas energizantes y sus efectos en la cavidad oral. Desarrollo: se pudo encontrar varias asociaciones entre el consumo de bebidas energizantes, y la afectación en la salud oral, especialmente aquella alteración definida sobre tejidos duros del diente, como la erosión o desgaste dental, con algunos estudios in vitro se pudo concluir que un ambiente y pH ácido, puede perjudicar y predisponer al desgaste de minerales del tejido dental luego de una exposición prolongada, sobre todo en casos donde la presencia de saliva disminuya, ya que deja de cumplir con su papel limpiador y amortiguador. Conclusiones: el consumo excesivo de bebidas energizantes puede influenciar en la salud oral, se encontró en varias revisiones bibliográficas que los componentes que contienen las bebidas energéticas pueden causar enfermedades no solo a nivel oral, sino además a nivel sistémico, una de estas sustancias es la cafeína.

Cassava peels were modified with citric acid by reacting the dried and milled peels with an aqueous solution of citric acid at 60 °C and sulfuric acid as catalysts, and subsequent heating at 150 °C for completion of the reaction. The synthetic solutions were preparing taking 0,5 g of metallic gold and dissolving it in a solution of 8 ml of HNO3 0,1 M; volume was completed until a solution of concentration in gold of 500 mg/L was reached. The influence of variables such as the initial gold concentration, temperature, and pH of the samples were analyzed in order to determine the optimum conditions in the recovery process. Experiments were carried out in Erlenmeyers in batch mode using an orbital shaker. The activation energy of the adsorption process was calculated as 157 + 14 kJ/mol. Gold removal values were found up to 99,58%, at a temperature of 45 ° C and pH of 10, these being optimal conditions. [ABSTRACT FROM AUTHOR]

Contextualization: Matrix Engineering uses the vacuum impregnation technique [IV] to confer added value to porous food structures. Knowledge gap: Is the application of antioxidant solutions effective, using the vacuum impregnation process, to control the browning on fresh hearts of Iraca palm? Purpose: The object of the investigation was to [experimentally] optimize a formulation of antioxidants, with the technique of IV, to improve the color of hearts of Iraca palm (PI) with diameters between 10 - 12 mm and length of 4 cm. Methodology: To evaluate the formulation was used a response surface methodology, with a central compound design, [α=1], considering these independent variables [VI: citric acid [CA] [100-300 mg for each 100 g of PI], ascorbic acid [AA] [12-24 mg for each 100 g of PI), sodium bisulfite [SB] [500-1500 ppm]. The dependent variables valuated were [VD]: volumetric fraction of impregnation and volumetric deformation in the vacuum stage [X1 and g1 respectively], fraction and final volumetric strain [X and g, effective porosity of IV [Ee], and color changes in the longitudinal and radial zones [ΔELongitudinal y ΔERadial respectively] after 3 days of storage under refrigeration. In addition, the formulation contained NaCl [0,6 %] and ethylenediaminetetraacetic acid [75 mg for each 1000 g PI]. Besides, the IV process was effected under these conditions: PI with diameters between 10 and 12 mm and 4 cm length, vacuum pressure [4,1 kPa], atmospheric pressure [85,3 kPa], time in vacuum [4,5 minutes] and time according to the atmospheric pressure [4,0 minutes]. Results and conclusions: The formulation of the impregnation suspension, used for the optimization, was determined as follows: CA = 165,8 mg for each 100 g of PI, AA = 16,5 mg for each 100 g of PI, and SB = 1500 ppm; The IV parameters were: X1 = 17,1%, g1 = 0,131%, X = 20,0%, g = -0,645% y Ee = 23,6%, and the effect of the impregnation solution allowed the following values: ΔELongitudinal = 4,9 y ΔERadial = 9,1. PI contains a food matrix suitable for the IV process with antioxidant solutions, allowing the control of the enzymatic browning in its structure. Additionally, the VI technique used provides alternatives for the incorporation of active compounds to PI; as flavor and texture improvers, among others, that will contribute to generate a greater value in the food production system. [ABSTRACT FROM AUTHOR]

O mesocarpo de pequi é um coproduto que pode ser reutilizado através da extração de substâncias como as pectinas. As pectinas podem ser usadas como matéria-prima para a produção de filmes biodegradáveis. O objetivo deste trabalho foi a extração do mesocarpo de pequi e a caracterização dessas substâncias, através do espectro infravermelho e produzir filmes. A extração da pectina foi realizada por esquema fatorial 2³, com variação nas condições de concentração do ácido cítrico (0,5; 0,75 e 0,8 M) e no tempo (25; 50 e 75 min). O grau de esterificação das pectinas extraídas foi analisado usando a transformada de Fourier (FTIR) com um espectrômetro de infravermelho. O tratamento com maior grau de esterificação foi utilizado para a produção de filmes pelo método de casting. Os filmes foram avaliados quanto as propriedades mecânicas. O rendimento da extração aumentou com o aumento do tempo de extração. As pectinas extraídas apresentaram alto e baixo grau de esterificação na qual foi possivel visualizar pelas bandas do espectro infravermelho. As características mecânicas dos filmes de pectina foram melhores quando usadas apenas em pectina comercial.

A total of 240 Arbor acre (AB) and 240 Cobb 500 (CO) broiler chickens given Ficus exasperate leaf powder (1%FELP) and 200mg/kg Vitamin C (VC) supplemented diets were studied for performance and blood indices. Diets 1 and 2 (controls) were fed to AB and CO, respectively; Diets 3 and 4 (VC supplemented) were fed to AB and CO, respectively; Diets 5 and 6 (FELP supplemented) were fed to AB and CO, respectively; while diets 7 and 8 (VC+FELP supplemented) were fed to AB and CO, respectively. At 6 age weeks, body weight gain (BWG) of CO improved (P<0.05) over the AB birds, while VC improved BWG of CO over AB. VC improved the feed conversion ratio (FCR). VC and FEPL increased the packed cell volume and the red blood cell (RBC); while the RBC of CO was higher (P<0.05) than AB. The VC and FELP increased the haemoglobin concentration. The white blood cell count improved (P<0.05) by FELP. The VC and VC x FELP reduced (P<0.05) the serum aspartate aminotransferase concentration. VC and FELP reduced (P<0.05) the serum creatinine concentration. The FELP reduces (P<0.05) the serum cholesterol. Conclusively, CO and 200 mg/kg Vitamin C supplementation support optimal body weight gain. For better immunity and hypocholesterolemia, 1 % FELP supplementation is indicated; while 1 % FELP might be coupled with 200 mg/kg Vitamin C to enhance feed consumption, red blood cell count, packed cell volume, haemoglobin concentration; to prevent liver and tissue damage and protect renal cells from damage in broiler chickens. [ABSTRACT FROM AUTHOR]

Fresh-cut apples were subjected to mild vacuum impregnation (Vacuum pressure=67.7 mbar). M0: 30 °Brix honey solution (HS); M0.5: HS+0.5% citric acid (CA)+0.5% ascorbic acid (AA); and M1: HS+1% CA+1% AA were used as osmotic solutions. Changes in soluble solids (SS), pH, firmness, color (ΔE*ab), total phenolic and vitamin C content, and antioxidant capacity were evaluated on days 0 and 7 of storage at 1.5 °C. Mass transfer parameters were calculated. The best results were obtained with the M1 treatment. Vacuum-impregnated fresh-cut apples gained solids (3.3%) and weight (1.6%) and lost water (1.8%). The following modifications were observed on day 0: an increase of SS (26%), a reduction in firmness (14%), a slight color change (ΔE*ab=3.3), a great increase in vitamin C content (31 times higher than in fresh-cut fruits) and increases in total phenolic content and antioxidant capacity (27% and 77%, respectively). On day 7 of storage, an additional reduction of firmness was observed, but the other attributes were maintained or increased. The M1 treatment is an appropriate alternative for processing fresh-cut apples and obtaining improved healthy attributes. [ABSTRACT FROM AUTHOR]

The food industry represents an important economic sector worldwide. Cuba, being a highly sugar-producing country, is in turn a producer of different types of sweetener syrups. In this work, a study of the variation of acid concentrations is carried out in 10 variants of syrup preparations in order to determine its influence on the hydrolysis process and on the established sensory quality parameters. We find that the amount of acid influences the concentration of reducing sugars as well as the pH of the solutions; besides, the dissolved and insoluble solids do not depend on the dose of added acid. Through sensory evaluation, we determine that the sample with the least amount of citric acid is the one with the best taste on the palate. The economic evaluation shows that with the reduction of citric acid in the process (7 kg per temper to 1 kg per temper), a saving of 66 CUC per temper is achieved, making the process more profitable. [ABSTRACT FROM AUTHOR]

Introducción: La industria ecuatoriana consume grandes cantidades de ácido cítrico. Este producto es utilizado como conservante y antioxidante natural. Dentro de las materias primas que se pueden utilizar está el bagazo y en la provincia de Pastaza existe disponibilidad de este residuo que se obtiene de la fabricación artesanal de panela y no es aprovechado. Objetivo: Diseñar el proceso tecnológico para la obtención de ácido cítrico a partir del bagazo de caña disponible en la provincia de Pastaza. Materiales y Métodos: Se utilizó un procedimiento para el diseño del proceso y la herramienta informática SuperPro Designer para simular cuatro cantidades de consumo de bagazo para el proceso tecnológico seleccionado, que comprende el acondicionamiento, pretratamiento, fermentación sólida, separación y purificación. Resultados y Discusión: Considerando las posibles capacidades de la planta con respecto al consumo de materia prima se obtuvo que si se consumen 68,35 t/d el Valor Actual Neto es positivo. Por lo tanto, a partir de esa capacidad se pueden generar ganancias. Los residuos generados en la producción de ácido cítrico son yeso, biomasa, lignina, hidrolasas y emisiones de CO2. Estos se destinan para la producción de nuevos productos o energías para reducir el impacto ambiental. Conclusiones: Se diseñó el proceso tecnológico para la obtención de ácido cítrico en la provincia de Pastaza, del cual se realizó el análisis económico de las capacidades de 60, 72, 84 y 96 toneladas de bagazo teniendo como resultado un VAN de -3 021 000, 1 217 000, 5 827 000 y 10 576 000 USD respectivamente, lo que permitió encontrar una ecuación que predijo el comportamiento del VAN.

Copyright of Revista de Ciencias Agricolas is the property of University of Narino, Faculty of Agricultural Sciences 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 Avances en Odontoestomatologia is the property of Ediciones Avances SL 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.)

Resumo Kiwis minimamente processados necessitam de técnicas para manter a qualidade dos frutos durante a conservação e o período de prateleira. Aditivos combinados à radiação ultravioleta podem ser uma alternativa para assegurar a qualidade das frutas por mais tempo de conservação. Neste contexto, foi proposto avaliar a eficiência do uso da radiação UV-C e diferentes aditivos na prevenção do escurecimento e conservação de kiwis ‘Bruno’ minimamente processados. As fatias de kiwi foram submetidas a soluções contendo os seguintes tratamentos: controle, ácido ascórbico a 1%; isoascorbato de sódio a 1%; ácido cítrico a 1%, depois, utilizou-se por dois minutos a radiação UV-C na intensidade de 2,71 kJ m-2. As bandejas foram armazenadas em câmara fria a 4 ± 1 ºC de temperatura, com umidade relativa de 85% a 90%, e armazenadas por períodos de 3, 6 e 9 dias. Avaliaram-se perda de massa, coloração da polpa, sólidos solúveis, acidez titulável, incidência de podridão, compostos fenólicos totais e atividade antioxidante. O uso de aditivos melhora a conservação do kiwi minimamente processado, com destaque para o isoascorbato de sódio e o ácido cítrico. Os frutos de kiwi da cultivar ‘Bruno’ podem ser armazenados por até 6 dias sob refrigeração com o uso de aditivos. Após esse período, a perda de massa é elevada. O uso de UV-C não alterou a qualidade dos kiwis durante o armazenamento, podendo ter seu uso dispensado.

Chihuahua produce el 66 % de la manzana (Malus x domestica Borkh) a nivel nacional, siendo el cultivar ‘Golden Delicious’ el de mayor superficie plantada. La necesidad de controlar la maduración de la fruta para programar la cosecha, ha condicionado el uso de productos a base de la aminoetoxivinilglicina (AVG), un inhibidor de la síntesis del etileno, y por lo tanto de la maduración de los frutos climatéricos. Este producto es eficaz, pero de alto costo. En este estudio se evaluó la eficiencia de productos alternativos al AVG de menor costo. Se asperjaron manzanos ‘Golden Delicious’ en precosecha durante el ciclo 2008, con los tratamientos: ácido salicílico (AS; 1, 0.1 y 0.01 μM), cobalto (40, 60 y 80 mg Co++·L-1), ácido cítrico (AC; 533 mg·L-1) y AVG (123 mg·L-1) y agua como testigo. Los tratamientos de AS (0.01 y 1.0 μM) y de AC redujeron significativamente la concentración interna de etileno en los frutos, en comparación con el testigo, y a un nivel similar al AVG, con concentraciones de etileno de 0.6, 0.6, 0.4, 1.7 y 0.4 ppm, respectivamente. Los tratamientos con cobalto, a 40 y 80 mg Co++·L-1, retrasaron el pico climatérico en tres semanas. Los tratamientos con AS y cobalto indujeron frutos con color de cáscara más verde y con menor concentración de sólidos solubles, indicando un estado menos avanzado de maduración. Los tratamientos precosecha con AS, AC, y cobalto, representan una herramienta en el control de la maduración de manzanas ‘Golden Delicious’. Abstract Chihuahua produces 66 % of the apple (Malus x domestica Borkh) production in Mexico, being ‘Golden Delicious’ apple cultivar the most widely planted. The need to control fruit maturation in order to schedule harvest has made the use of aminoethoxyvinylglicine (AVG) almost a must, since it is an efficient ethylene synthesis inhibitor, and therefore a retardant of the maturation process in climacteric fruits; however it is an expensive product too. In this trial the effectiveness of alternative products to AVG, at a lower sell price, were evaluated. ‘Golden Delicious’ apple trees were sprayed before harvest during the 2008 season with: salicylic acid (AS; 1.0, 0.1 and 0.01 μM), cobalt (40, 60 and 80 mg Co++·L-1), citric acid (AC; 533 mg L-1), AVG (123 mg·L-1) and water as control. The treatments with AS (0.01 and 1.0 μM) and with AC reduced the internal concentration of ethylene in the fruit respect to control, and to a similar level as AVG did it, with internal ethylene concentration of 0.6, 0.6, 0.4, 1.7 and 0.4 ppm, respectively. Treatments with cobalt at 40 and 80 mg Co++·L-1 delayed in three weeks the climacteric peak. AS and cobalt produced fruits with greener peel and lower level of soluble solids, indicating a less advanced maturation stage. Therefore, the preharvest treatments with AS, AC and cobalt offer to growers a tool to control the maturation of ‘Golden Delicious’ apple fruits. Keywords: Malus x domestica, citric acid, salicylic acid, cobalt.

Objetivo: Evaluar con microscopía electrónica de barrido (MEB) la remoción de barro y erosión al irrigar los canales radiculares con cuatro soluciones ácidas. Métodos: Se utilizaron 30 premolares inferiores uniradiculares divididos en cinco grupos según tipo de irrigación: Grupo 1 Control: NaOCl 5,25%. Grupo 2: NaOCl 5,25% + ácido etilendiaminotetraacético (EDTA) 17%. Grupo 3: NaOCl 5,25% + ácido maleico 5%. Grupo 4: NaOCl 5,25% + ácido cítrico 10%. Grupo 5: NaOCl 5,25% + ácido fosfórico 37%. Se realizaron 90 microfotografías con MEB a 5000x a 2, 6 y 10 mm de la longitud de trabajo. Resultados: Se encontró diferencia significativa de la remoción del barro dentinario entre el grupo control y los demás grupos (p

A coating elaborated with modified cassava starch was applied by acid route, to evaluate the post-harvest behavior of the tomato under environmental conditions, determining its effect on the microbiological and structural characteristics. The modification of native starch of cassava variety SM 707-17 was carried out by addition of citric acid (15% w/w with respect to starch on dry basis) to a suspension of starch subjected to controlled conditions of temperature and speed of agitation. The effect was compared with that of the application of others elaborated based on enzymatically modified starch and native starch, being T1: control sample; T2: coating with enzymatically modified starch; T3: coating with starch modified with citric acid and T4: coating with native starch. The application was made manually with clean and sterile sponge; The tomatoes were placed in labeled trays, allowing to dry for 24 h at room temperature, from which the microbial growth and microscopic characterization of the tomato exocarp was measured for 15 days, applying a completely randomized 4x6 factorial design that had consider the type of related and independent samples; the data obtained were analyzed using SPSS software version 19, which found that the "Coating" factor did not influence the response variables analyzed, unlike the "Time" factor that had a decisive effect on them. [ABSTRACT FROM AUTHOR]

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Introduction: The Ecuadorian industry consumes large amounts of citric acid. This product is used as a preservative and natural antioxidant. Among the raw materials that can be used is bagasse. There is availability of this residue in Pastaza province that is obtained from the panela handmade manufacture is not used. Objective: Design a technological process for obtaining citric acid from sugar cane bagasse available in Pastaza province. Materials and Methods: A procedure was used for process design and SuperPro Designer software tool to simulate four quantities of bagasse consumption for the selected technological process that includes conditioning, pretreatment, solid fermentation, separation and purification. Results and Discussion: Considering the possible plant capacities with respect to the raw material consumption, it was obtained that if 68.35 t/day are consumed, the Net Present Value is positive. Therefore, from that capacity profits can be generated. The wastes generated in citric acid production are gypsum, biomass, lignin, hydrolases and CO2 emissions. These are intended for new products or energy production in order to reduce the environmental impact. Conclusions: The economic analysis for capacities of 60, 72, 84 and 96 tons of bagasse carried out for citric acid technological process designed in Pastaza province, resulting in a NPV of -3 021 000, 1 217 000, 5 827 000 and 10 576 000 USD respectively, which allowed to find an equation that predicted NPV behavior. [ABSTRACT FROM AUTHOR]

Se estima que en los próximos años a nivel mundial habrá carencia de las fuentes de fósforo (P) utilizadas para fabricar los fertilizantes fosforados. Aunque el P puede encontrarse en el suelo, la mayor parte se encuentra en forma no asimilable por las plantas, por lo que para absorberlo éstas exudan ácidos orgánicos (AO) para facilitar su solubilización. Por otro lado, se ha reportado que la presencia de aluminio (Al) se relaciona con un aumento en la exudación de AO por la raíz. Dado la capacidad solubilizadora de los AO, en el presente estudio se planteó evaluar el efecto de la aplicación de Al sobre la exudación de AO y el uso de P en forma no soluble (roca fosfórica, RF) en el crecimiento y rendimiento de plantas de fresa. El experimento constó de ocho tratamientos que resultaron de combinar dos cantidades de RF, mezcladas en el sustrato, con aplicaciones de Al. Los tratamientos con RF se irrigaron con una solución que contenía 0.25 meq L‑1 H2PO4‑. Los resultados mostraron que con aplicaciones de Al vía riego se obtienen mayores rendimientos, hasta 380 g planta-1, lo cual estuvo correlacionado positivamente con la concentración de ácido cítrico y negativamente con la concentración de ácido málico en el sustrato. Se concluye que el citrato exudado por la raíz debido a la aplicación de Al, favorece el rendimiento de plantas de fresa cuando el P se encuentra en forma de RF.

This work describes a method for the simultaneous determination of organic acids in fungi fermentation broths. The sample preparation technique and the chromatographic conditions were optimized to enable the monitoring of the fermentation process. The determination of the citric and oxalic acid was done with a high resolution liquid chromatograph adapted to a detector with diode arrangement, an IC-Pak Ion-Exclusion 7μm (7.8 x 300 mm) column and a mobile phase of 0.001N H2SO4 with isocratic elusion. The validation parameters show efficiency, adequate linearity, and standard deviation values (%RSD) from 0.018% and 4.650%. the quantification limits (LDC) were 50.76 mg/L for citric acid and 20.18 mg/L for oxalic acid and the detection limits (LDD) were 0.6 mg/L for both acids. The method was applied in the analysis of organic acids in fermentation broths of Aspergillus niger. [ABSTRACT FROM AUTHOR]

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Copyright of Revista ADM is the property of Asociacion Dental Mexicana 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 Latinoamericana de la Papa is the property of Asociacion Latinoamericana de la Papa (ALAP) 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.)

Different conditions of sugarcane bagasse pretreatment were evaluated using citric acid, considering in further analysis the combined severity factor. Temperature, time and citric acid concentration were used as input variables. In a Gas Chromatographer Perkin Elmer-Clarus 400, the levels of xylose, glucose and hemicellulose were determinate. Initial recovery rate are also determinate for each pretreatment condition in addition to combined severity factor. The linearity was demonstrated between: the release of xylose and hemicellulose, the xylose and initial material recovery and between hemicellulose and combined factor of severity. Linear correlation coefficients were higher than 0.75 in all cases, with statistic significance greater than 95%. Three empirical models are reported that were adjusted to predict the release of xylose, hemicellulose and initial material recovery. [ABSTRACT FROM AUTHOR]

Resumo A prevalência da nefrolitíase está aumentando em todo o mundo e resulta em ônus significativo para o sistema de saúde. Novos estudos revelam que a formação de cálculos urinários está associada a várias morbidades graves. No entanto, poucos estudos observacionais ou ensaios clínicos randomizados de qualidade demonstraram que intervenções clínicas específicas diminuem a recorrência da nefrolitíase. Portanto, nesta revisão são analisadas as evidências disponíveis da terapia médica expulsiva para cálculos ureterais; avaliam-se os dados da terapêutica não farmacológica, incluindo modificações dietéticas e terapia à base de sucos cítricos; e discute-se a eficácia dos diuréticos tiazídicos no tratamento da hipercalciúria associada à nefrolitíase recorrente.

Resumo Polímeros termoplásticos podem ser utilizados como veículo orgânico (VO) em processos de conformação de peças cerâmicas por extrusão. Neste contexto, termoplásticos à base de amido surgem como uma alternativa sustentável ao emprego das poliolefinas convencionalmente utilizadas na formulação de pastas cerâmicas. O passo inicial para o desenvolvimento de um feedstock (carga extrudável) é a seleção adequada do sistema polimérico ligante, o qual é responsável por conferir propriedades reológicas adequadas durante o processamento. O presente trabalho se propôs a caracterizar termoplásticos a base de amido obtidos na presença de ácido cítrico e avaliar o potencial de utilização destes materiais na extrusão de pós cerâmicos. A processabilidade das pré-misturas de amido foi avaliada em extrusora dupla-rosca e em reômetro de torque. A variação dos teores de água e glicerol na composição das pré-misturas de amido influenciou significativamente as interações entre as cadeias poliméricas, promovendo alterações nos valores de densidade e de viscosidade para a maior parte das amostras analisadas. O amido foi parcialmente esterificado como efeito da ação do ácido cítrico no sistema. Dentre as formulações investigadas, a amostra hidratada e processada com 34% p/p de glicerol (H-34) foi a que apresentou as melhores propriedades de pasta, podendo ser futuramente empregada em processos de conformação de pós cerâmicos.

Se estudia la adsorción de Cr (VI) a partir de biomasa residual: bagazo de palma y cáscaras de ñame, además se estudia la modificación con ácido cítrico de las biomasas. La determinación del metal en solución fue llevada a cabo usando el método de la 1,5-difenilcarbazida. Del análisis FTIR se encontró que los grupos hidroxilo y carbonilo presentes en los adsorbentes son los de mayor contribución al proceso de remoción. Además, la modificación mejora la eficiencia del metal de acuerdo con la isoterma de Langmuir de 13 a 4mg/g para el bagazo de palma, y de 22 a 26mg/g para las cáscaras de ñame. Se establece además una mejora en el proceso al trabajar las biomasas en sistema continuo. De las condiciones óptimas de adsorción se determinó que el pH de 2 y el tamaño de partícula de 1mm son las que más favorecen el proceso, y el modelo de Elovich el que mejor lo describe.

Faustino Jovita Malaguti (1802-1878), an Italian-French pharmacist, proved that diluted, even very diluted acids, at temperatures below 95 0C, acted in an identical manner upon sugar and that the final result was a mixture of ulmic and formic acid or only ulmic acid, depending if the reaction was conducted in the presence or absence of atmospheric air. Malaguti studied the preparation of mucic and paramucic acid and their derivatives, ethyl citrate and the formula of citric acid, crystalline camphoric acid by the prolonged action of nitric acid on camphor, the preparation and properties of several derivatives of camphoric acid, studied the chlorination of a large number of ethers to prove that the assumption of the substitution theory that one atom of hydrogen could be replaced by one atom of chlorine. His results helped establish the substitution theory and dethrone the chemical theory of Berzelius. Malaguti prepared a large number of pure amides and discovered many new ones, among them mucamide, pyrotartramide, pimelamide, and adipamide. He demonstrated that cystine contained sulfur, carried on the synthesis of pigments for porcelain, the chloroesters and amides of a large number of organic acids, the reciprocal relations between soluble and insoluble salts, the effect of passage of sunlight through different liquids, etc. [ABSTRACT FROM AUTHOR]

The silver nanoparticles (Ag NPs) in the vase solutions are antimicrobial agents and ethylene inhibitors in some species for cut flowers, but the combined effect of sucrosesucrose and citric acid remains uninvestigated. The biosynthesis of Ag NPs with plant extracts is an efficient and ecologically friendly method. The objective of the present study was to evaluate the effect of sucrosesucrose and citric acid in combination with 1 ppm NPs of Ag in the vase life of Rosa hybrida cv. Freedom. The NPs were synthesized with Camelia sinensis extract and characterized them with UV-Vis spectrometry and Transmission Electron Microscopy. The design was completely randomized and the treatments were: 1) 1 ppm Ag NPs; 2) 1 ppm Ag NPs + 2% sucrosesucrose (pH 6); 3) 1 ppm Ag NPs + citric acid (pH 3), d) 1 ppm Ag NPs + citric acid + 2% sucrosesucrose; 4) control (distilled water, pH 6). The experimental unit was a floral stem with 15 replicates per treatment. The treatment 1 ppm NPs + citric acid generated the longest vase life (7.3 d), the highest water consumption (147.08 mL) and the highest relative fresh weight (89.50%). The treatments with AgNPs alone and AgNPs + citric acid delayed the maximum floral opening (5.33 d and 6.80 d) with respect to the control (3.13 d); variable related to the longevity of the flower. The presence of AgNPs in the solution inhibited bacterial growth but the citric acid increased the water consumption and the fresh weight of the floral stem. The presence of sucrosesucrose in the solution reduced the vase life, the consumption of water and increased the bacterial count but the acidification of the medium with citric acid partially reversed the negative effect of sucrosesucrose. [ABSTRACT FROM AUTHOR]

Samuel Baup (1791-1862), a Swiss pharmacist, understood the medical importance of iodine and its derivatives and prepared, for the first time, iodized potassium iodide starting from the reaction of iodine with iron. The resulting iodized iodine was then reacted with potassium carbonate or bicarbonate. His work on alkaloids led to the description of the properties of quinine supersulfate, the synthesis and properties of cinchona supersulfate, quinic acid, and a large number of new quinates and aconitates. Baup separated and identified the acids produced by the pyrolysis of citric acid and those present in rosin, and demonstrated the existence of several sulfates of cinchona and quinine. The pyrolysis of citric acid led to the synthesis of the new acid, citricic acid. He also extracted a variety of new substances from plants, for example, abietic and pinic acids from rosin, breine from the resin of Parkinsonia praecox, solanine from potatoes, and elemin from the resin of Amyris elemifera. He also carried extensive work on the determination of better values of the atomic mass of a variety of elements, particularly carbon, calcium and gold, and the molecular mass of important compounds such as water, carbon monoxide, and carbon dioxide. [ABSTRACT FROM AUTHOR]

Copyright of Agronomía Colombiana is the property of Universidad Nacional de Colombia 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.)

Strawberry production in Paraguay is carried out by small producers, using minimal technology and obtaining low productivity, with the need to expand strawberry genotypes and production techniques. The aim of this study was to evaluate fruit quality of strawberry genotypes according to vernalization. A randomized block design with factorial arrangement 14x2 was performed; factors were genotypes and chilling using 15 plants per treatment and three replicates. Plants were kept in cold room at 5°C, with 8 hours of artificial light and 16 of darkness for a period of 25 days. Five fruits were used per treatment and were evaluated as follows: the amount of total soluble solids, titratable acidity and ratio of total soluble solids to titratable acidity, length/diameter ratio, calyx diameter/fruit diameter ratio, peduncle length and mass loss in postharvest. Data obtained were subjected to analysis of variance simple factorial scheme and averages compared by Tukey test at 5% probability. Vernalization of strawberry plants did not affect fruit shape or total soluble solids content, but increased the percentage of citric acid. Length of peduncle and calix extension had achieved an increasing due to vernalization and decreased postharvest loss of fresh mass, but did not affect fruit preservation at 5°C. Festival and Florida Eliane genotypes may be recommended for in natura consumption and Dover and Oso Grande genotypes for industry. [ABSTRACT FROM AUTHOR]

Fue evaluada la aceptabilidad para una bebida de maíz morado endulzada con Stevia cristalizada 100% natural, Ácido Cítrico como acidulante y propóleos diluidos en etanol al 8% como conservante. Como diseño experimental se utilizó un Diseño de Mezclas Simplex con Centroide Ampliado, a través de 10 tratamientos con diferentes concentraciones de Stevia entre 3,6 – 4,67 g, Ácido Cítrico entre 1,5 -2,33 g y Propóleos entre 0,33 – 1,0 g que fueron basadas en 1 Kg de bebida de maíz morado variedad canteño. La evaluación de la aceptabilidad, se realizó mediante un panel sensorial de 40 panelistas escogidos al azar, utilizando una escala no estructurada con puntuación de 1-10 para evaluar la aceptabilidad de la bebida preparada. Los resultados obtenidos mostraron que, para obtener una mayor aceptabilidad de la bebida de maíz morado variedad canteño (Zea Mays L.), los rangos óptimos en cuanto a concentración de Stevia son de 3,6-4,1 g/1 kg de bebida, ácido cítrico 1,92-2,33 g/1 kg de bebida, y propóleos 0,3-0,67 g/1 kg de bebida

En la investigación se evaluaron el rendimiento (%) y la productividad (g/lt por hora) de la fermentación sumergida de ácido cítrico con el uso de una cepa de Aspergillus niger mejorada por exposición a luz UV, cuando se incrementa el nivel de potasio (K) y reduce el nivel de fósforo (P) en una formulación de base que contiene sacarosa, micro- y macronutrientes. Se evaluaron cinco tratamientos en un diseño completamente al azar con tres repeticiones en una estructura multifactorial completa aumentada 2² + punto central. Los mejores resultados de rendimiento y productividad se obtuvieron con 329 mg/ lt de P y 271 mg/lt de K (tratamiento 2), equivalentes a 63.2% de rendimiento y 1.20 g/lt por hora de productividad. Se encontró que sólo el potasio es altamente significativo y que no existe interacción significativa entre K y P, adicionalmente los resultados obtenidos podrían generar una reducción en los costos de producción de ácido cítrico. A partir del análisis de regresión de superficie de respuesta se obtuvieron modelos útiles para predecir los resultados de productividad y rendimiento de la fermentación de ácido cítrico dentro del rango de evaluación. Igualmente se encontró que el 8.01% de la variación total para la productividad y el 48.94% de la variación total para el rendimiento no se explican con el modelo. Los resultados obtenidos son diferentes a los reportados por otros autores debido a que estos han utilizado condiciones sub-óptimas para asegurar la máxima acumulación de ácido cítrico y/o cepas de colección las cuales se caracterizan por una menor productividad en ácido cítrico en comparación con las cepas industriales (Papagianni, 2007).

Introduction: as part of endodontic treatment, root canals are cleaned and shaped, since shavings of dentin and organic materials, such as microorganisms, resulting from the action of instrumentation, create the so-called dental smear. Objective: carry out an in vitro evaluation of smear layer removal and dentinal tubule density reduction using chelating irrigation solutions. Methods: an experimental study was conducted for which 30 single-rooted human teeth were selected after initial radiographic examination to verify the presence of a single canal, absence of calcification, internal resorption and endodontic treatment either completed or underway. Next, instrumentation was performed with three different irrigation solutions: 17% ethylenediaminetetraacetic acid, 10% citric acid and 5.25% sodium hypochlorite (control group). Each instrumented tooth was then evaluated radiographically using a density scale made of aluminum with different density markers. Scanning electron microscope analysis was performed on three teeth from each group, which were treated with different irrigation solutions. Seven teeth from each group were infiltrated with methylene blue to determine marginal infiltration under the stereomicroscope. The teeth were evaluated on their three thirds: cervical, middle and apical. Results: radiographs did not reveal any statistically significant difference between the mean densities of the different groups of teeth in all thirds. Scanning electron microscopy showed a statistically significant difference between the three groups of irrigation substances (p