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Various definitions have been established on soil fertility; however, the definition is broad and complex since it depends on the supply of nutrients and other edaphic, environmental factors and the management to which this medium is subjected. The aim of this review has been to integrate various considerations that have been taken regarding the definition of soil fertility in a spread way and present in a broad way results that characterize the fertility of the main Cuban soils. The definition of soil fertility must be broad and complex, since it depends on the supply of nutrients and edaphic, environmental factors, and the management to which this medium is subjected. Based on what has been expressed and considering the complexity of the system where the soil is inserted, the definition of soil fertility is proposed as "the result of the interaction between the plant, the properties of the soil, the environment, the socio-economic phenomena and anthropogenic activity, which give it the ability to serve as a support and supply nutrients in the forms, quantities and proportions that plants require to achieve their growth and development". In the work, chemical, physical-chemical, morphological, physical, biological properties are presented, as well as the impact of socio-economic activities and anthropogenic activity that characterize the fertility of the main Cuban soils. [ABSTRACT FROM AUTHOR]

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El término suelo tropical es usado comúnmente para identificar cualquier suelo de los trópicos y se emplea como sinónimo de suelos rojos muy meteorizados, ácidos e infértiles. Es verdad que los suelos con estas peculiaridades están localizados en los trópicos, pero no todos los suelos de los trópicos, y en particular los de Ecuador, tienen estas características. La modificación del normal proceso de meteorización, debido al cambio de la cantidad e intensidad de las lluvias, el aporte de nuevo material parental como la ceniza volcánica y la diferencia altitudinal y de temperatura que origina la cordillera de los Andes, generó la posibilidad de que Ecuador, un país localizado sobre la línea ecuatorial, tenga una variedad de suelos que soporta una de las mayores expresiones de diversidad de vida sobre el planeta. Desde el punto de vista de producción agrícola, la relación existente entre la mineralogía con la química y la fertilidad del suelo define las prácticas de manejo para las condiciones particulares de los suelos de Ecuador. Los suelos dominados por arcillas de tipo 2:1, como montmorillonita y vermiculita, que se caracterizan por tener carga permanente, deben manejarse de forma diferente a los suelos de carga variable, como los suelos dominados por arcillas de rango corto, como alofana, imogolita, y por complejos humus aluminio (suelos de origen volcánico) y aquellos dominados por caolinita y sesquióxidos de hierro y aluminio. La producción de cultivos se limita considerablemente cuando un suelo es ácido o cuando los contenidos de fósforo son bajos y el manejo de los suelos afectados por estas condiciones depende del tipo de carga eléctrica de las arcillas del suelo. El control de la acidez del suelo es una práctica común en las regiones con suelos ácidos en el mundo, sin embargo, el modificar el pH para lograr condiciones adecuadas para los cultivos depende del tipo de arcillas presentes en el suelo y, por esta razón, no existe una recomendación general de encalado para todos los suelos del Ecuador. De igual manera, las reacciones de adsorción (fijación) de fósforo ocurren con preferencia en los suelos de carga variable. Esta ponencia discute ampliamente las condiciones que afectaron el material parental que llevaron a la presencia de suelos de carga permanente y carga variable en Ecuador y las estrategias para manejar acidez, salinidad y fósforo en los diferentes suelos del país.

O objetivo deste trabalho foi avaliar a qualidade físico-química e microbiológica de cremes de leite UHT comercializados no estado de Pernambuco, classificados quanto ao teor de gordura como creme e leve. Foram obtidas 40 amostras de creme de leite UHT das marcas A e B e 120 amostras de creme de leite leve UHT das marcas C, D, E, F, G e H, sendo dois lotes/marca e dez amostras/lote, totalizando 20 amostras de 200g por marca, provenientes de supermercados localizados nas Mesorregiões de Pernambuco: Metropolitana do Recife, Mata, Agreste e Sertão. As amostras foram coletadas e analisadas para acidez, gordura e pesquisa de aeróbios mesófilos no Laboratório de Inspeção de Carne e Leite da Universidade Federal Rural de Pernambuco. As duas (100%) marcas de creme de leite UHT (A e B) e as seis (100%) marcas de creme de leite leve UHT (C, D, E, F, G e H) atenderam aos padrões físico-químicos estabelecidos pela legislação vigente. Todas as amostras de creme de leite UHT, da marca B, e todas as amostras de creme de leite leve UHT, marca C, apresentaram valores de aeróbios mesófilos acima do padrão de 100 UFC/g, o que as caracterizam como impróprias à alimentação humana. Falhas nos programas de autocontrole de estabelecimentos de leite podem estar relacionadas ao excesso de microrganismos em amostras de creme de leite UHT e de creme de leite leve UHT, comercializadas no estado de Pernambuco.

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A maturação de laranjas e tangerinas consiste em modificações fisiológicas, químicas e morfológicas na casca, na polpa e no suco, que são cruciais para determinar as épocas de colheita de cada variedade. O rato, relação entre a acidez e o teor de açúcar do suco, é o principal parâmetro físico-químico que define a época de colheita, mas o aspecto visual, em especial a coloração, também é importante. A colheita no sul do Brasil estende-se de abril a fevereiro para as laranjas e de fevereiro a dezembro para as tangerinas, dependendo da variedade. Identificar os períodos de oferta de cada variedade é primordial para atender as demandas de consumo e obter os melhores retornos financeiros em períodos de baixa competividade com frutos de qualidade.

Clubroot disease, caused by Plasmodiophora brassicae, limits the production of Brassica spp. worldwide. Little is known about the factors related to the development of the disease in kale (Brassica oleracea var. acephala) plants and in crops in mountainous areas under tropical conditions. This study examined the severity of clubroot in kale crops as well as identify potential flaws in management and the soil and relief factors related to its occurrence. The study was conducted in 24 kale fields in the mountainous region of Rio de Janeiro (Brazil). Soil and kale growth management practices adopted in the region were identified and samples of soil and plants were collected. Subsequently, soil and relief attributes, disease severity, biomass and nutrient and Al contents and accumulation in the plants were determined. There was a high spread of the pathogen in the areas. Inappropriate and recurrent practices in the region were detected, e.g., sequential cultivation of host species, low adoption of soil fertility analysis and liming and conservation practices, and community use of agricultural machinery and implements without prior cleaning. The disease was associated with more acidic soils, subject to greater water accumulation and with high levels of Al3+ as well as with higher Al contents and accumulation in the roots. Management practices must be adopted in the region to reduce the potential inoculum of P. brassicae and to increase soil fertility. [ABSTRACT FROM AUTHOR]

Alta acidez do solo, baixa capacidade de troca catiônica e baixa fertilidade são os principais gargalos das atividades agrícolas na região amazônica, o que torna a calagem uma técnica essencial para a produção agrícola. Este estudo teve como objetivo avaliar a eficiência de dois métodos de calagem, a saber, a lanço e incorporado ao solo, para atender às exigências da saturação por bases (V%) em diferentes profundidades e intervalos de tempo em um Latossolo Amarelo na Amazônia oriental. O experimento foi realizado em delineamento de blocos casualizados em esquema fatorial 5 × 2, com cinco doses de calcário recomendadas para elevar o V a 0, 40, 80, 160 e 320% e dois métodos de aplicação (a lanço e incorporado). Após a aplicação do calcário, amostras de solo foram coletadas em três profundidades (0,00-0,05, 0,05-0,10 e 0,10-0,20 m) em três períodos (30, 60 e 90 dias após a aplicação, DAA) para determinação do V%. Os maiores valores de V% foram observados aos 30 DAA com incorporação. O valor de V% esperado foi obtido pela incorporação da dose de 40%, mas foi limitado às camadas de 0,00-0,05 e 0,05-0,10 m. A incorporação de cálcario é o método mais eficiente para atingir os níveis recomendados de V% aos 30 DAA. Aos 90 DAA, a maioria das doses não forneceu valores de V% iguais ou superiores aos valores calculados. Portanto, análises de regressão são recomendadas em experimentos de campo respeitando o limite de 80% V.

High soil acidity, low cation-exchange capacity, and low fertility are the major bottlenecks in the Amazon region's agricultural activities, making liming an essential technique for crop production. This study aimed to assess the efficiency of two liming methods, namely broadcasting and incorporation, in meeting base saturation (BS) requirements at different soil depths and time intervals in a Latossolo Amarelo in the eastern Amazon. The experiment was carried out using a randomized block design arranged in a 5 Ã--2 factorial, with five lime doses recommended for raising the BS to 0, 40, 80, 160, and 320% and two application methods (broadcasting and incorporation). After lime application, soil samples were collected at three depths (0.00-0.05, 0.05-0.10, and 0.10-0.20 m) and three periods (30, 60, and 90 days after application, DAA) for BS determination. The highest BS values were observed at 30 DAA with incorporation. The expected BS value was obtained by incorporating the 40% dose but was limited to the 0.00-0.05 and 0.05-0.10 m layers. Lime incorporation is the most efficient method for achieving the recommended BS levels at 30 DAA. At 90 DAA, most doses did not provide BS values equal to or greater than the calculated values. Therefore, regression analyses are recommended in field experiments respecting the threshold of 80% BS. [ABSTRACT FROM AUTHOR]

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Nesta pesquisa objetiva-se analisar aspectos químicos in vitro do potencial erosivo para estrutura dentária de bebidas energéticas e sua influência na absorção de nutrientes. As bases metodológicas utilizadas seguiram os padrões aceitos internacionalmente para as análises de potencial hidrogeniônico, acidez total titulável, sólidos solúveis totais e de açúcares redutores. Os resultados obtidos evidenciaram uma linha de produtos com elevada acidez, com medias entre 2,89 a 3,55 em potencial hidrogeniônico. Os teores para acidez total titulável oscilaram entre 0,26 a 0,80 g de ácido cítrico, com algumas diferenças significativas entre as amostras. Os conteúdos de sólidos solúveis totais apresentaram diferenças significativas entre todas as amostras. Os teores de açúcares redutores apresentaram médias que oscilaram de 26,42 a 131,65 g/L, com diferenças significativas de acordo com o teste de Tukey para p≤0,05. Os dados apresentados são preocupantes, pois as consequentes alterações na estrutura dentária afetam a ingestão de alimentos importantes à manutenção da saúde o que acarreta inadequações das taxas de absorção de micronutrientes. A partir desses dados concluímos há necessidade de ação conjunta interprofissional, com nutricionistas, odontologistas e de órgãos de fiscalização atuantes na observância continua da composição de alimento, com destaque para as bebidas industrializadas em virtude de sua ação sobre o surgimento da desmineralização e erosão do esmalte dentário, e a consequente redução do aporte no consumo de nutrientes regulatorios essenciais a boa nutricão.

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Tradicionalmente, en ambientes como laboratorios, el hogar o en lugares dedicados a la manipulación de alimentos, se suelen emplear desinfectantes de tipo sintético, que por el alto contenido de agentes químicos como el cloro, llegan a producir efectos perjudiciales para la salud. En la actualidad se han evaluado alternativas para producir y utilizar sustancias amigables con el medio ambiente, que sean lo menos nocivas posible, en este sentido se ha venido promoviendo el uso de desinfectantes ecológicos. En el caso de las cocinas, por ejemplo, la sobreexposición al uso de un desinfectante químico puede traer complicaciones al personal que labore allí y además el alimento pueda alterarse por efectos de la contaminación cruzada. Un ejemplo de alternativa de desinfección, que vale la pena revisar es el Vinagre, sus características químicas relacionadas con la presencia de ácido acético en concentración alta, puede desencadenar procesos de degradación más rápidos, que a su vez inciden en minimizar el riesgo tóxico asociado a sustancias químicas y sintéticas. Centrado en lo anterior, el semillero PGAE adscrito al programa de Ciencias Básicas de la Universidad Colegio Mayor de Cundinamarca orientó una revisión sistemática centrada en las propiedades químicas del Vinagre y de su constituyente fundamental (el ácido acético). Este trabajo fue presentado en la edición regional del encuentro de semilleros RedColsi (2021) en el marco de la investigación formativa y a continuación se relacionan los resultados más relevantes que sugieren la necesidad de realizar investigaciones centradas en el tema en cuestión, como una alternativa que pueda replicarse y usarse de manera generalizada en el marco de la química verde.

En épocas de escasez, los ganaderos recurren a conservar el alimento mediante procesos de fermentación anaeróbica, conocidos como ensilajes. Una vez que el silo es abierto, el sustrato resulta aeróbicamente estable, cuando, al momento de la apertura, conserva su integridad nutricional. Esto es el resultado de un ambiente ácido que restringe los efectos deletéreos de la acción de microrganismos patógenos, expresado en indicadores de estabilidad a la exposición aeróbica. Uno de los problemas empíricos que enfrenta el productor es resolver la pregunta de cómo evitar el deterioro del ensilaje, una vez es abierto, por lo cual, esta investigación apunta a la resistencia en el periodo de exposición aeróbica (PEA) de un ensilaje de Pennisetum purpureum (PP), con diferentes niveles de sustitución de Tithonia diversifolia (TD). El estudio, se adelantó en el Centro Internacional de Agricultura Tropical en Colombia. Con un ensilaje de 90 días de fermentación, se realizó una prueba de estabilidad aeróbica de siete días, usando ensilajes de un kilogramo, a diferentes proporciones (%) de TD/PP: 100/0, 67/33, 33/67 y 0/100, enriquecidos con dos aditivos basados en Lactobacillus. Se midió el cambio de la materia seca, temperatura y el pH, encontrándose una estabilidad a la exposición aeróbica. El papel de TD es notable, una vez que el ensilado entra en el PEA, debido a la capacidad tampón que amortigua el cambio de pH, una vez que se abre el silo, generando mayor estabilidad aeróbica.

"Olive" Olea europaea (Oleaceae) oil is obtained by mechanical grinding, whipping and centrifugation of the fruit of the olive tree, for the denomination of extra virgin oil it is necessary that the acidity is less than or equal to 0.8% expressed in oleic acid and a score less than or equal to 6.5 points, preserving the original polyphenolic compounds, which confer the great quality of taste and aroma. In this context, the present study aims to determine the stability of the sensory quality of extra virgin olive oil variety Farga and Frantoio with Farga in the period from March to October, according to the unidirectional analysis of variance there is no difference Statistical significance in the chemical results of acidity and peroxide index in the extra virgin olive oil of the Frantoio with Farga variety, unlike the extra virgin olive oil of the Farga variety that presented different values at the beginning and end of the evaluation period. It was determined that there is a significant correlation between the peroxide index and the sensory results, therefore, the authors consider that the extra virgin olive oil of the Frantoio with Farga variety presents greater stability than the extra virgin olive oil of the Farga variety. [ABSTRACT FROM AUTHOR]

Introducción. Jatropha curcas L. (JC), es una especie multipropósito con aplicaciones biológicas, farmacológicas e industriales. Su aceite es reconocido por la composición dominante de los ácidos grasos oleico-linoleico que lo hacen apto como biodiésel en motores de combustión interna, sin hacer cambios importantes al diseño del motor. Objetivo. Identificar en el aceite de cinco genotipos de JC en Colombia los índices de cetano, peróxido, yodo, el valor de acidez, el poder calorífico y verificar si cumplen con las normas para producción de biodiésel. Materiales y métodos. Se realizó un experimento en Espinal, Colombia, en un diseño de bloques completos al azar con cinco tratamientos y tres repeticiones. Los tratamientos estuvieron constituidos por cinco genotipos de JC. Se utilizó el fruto de la quinta cosecha en el año 2015. Del aceite se determinaron cinco ácidos grasos (oleico, linoleico, linolénico, palmítico y esteárico) y cinco factores químicos (índices de cetano, peróxido y yodo, acidez y poder calorífico). Resultados. El aceite de los cinco genotipos de JC evaluados en Colombia presentaron un perfil lipídico con predominancia de los ácidos grasos monoinsaturados (oleico C18:1) y poliinsaturados (linoleico C18:2). Los genotipos de JC evaluados en Colombia presentaron bajos índices de cetano, peróxido y yodo, baja acidez y alto poder calorífico. Conclusiones. Las propiedades de índices de cetano, peróxido y yodo, acidez y poder calorífico en los genotipos evaluados, cumplieron con las especificaciones de la Sociedad Americana de Ensayos y Materiales (ASTM) y de la europea (EN 14214), por lo que se catalogan como materia prima apropiada para la producción de biodiésel.

Oleoresin is obtained via tapping of pine trees and as a by-product of Kraft process in the pulp industry. Because of its low production cost, it is an attractive source for biofuels. Oleoresin is composed mainly of rosin (around 80%, a solid mixture of isomeric abietic acids), and it cannot be used directly as fuel in engines. However, the methyl ester of rosin has lower boiling and melting points than rosin, and it is highly soluble in hydrocarbons. Esterification of rosin with methyl alcohol was evaluated over acid and basic heterogeneous catalysts in the presence of several solvents. In contrast to acid catalysts, basic materials were active in the reaction. In particular, a low-cost calcium-based material showed the best performance. A 55% conversion of rosin with complete selectivity to methyl esters was obtained with 40% wt. loading of the calcium-based material (respect to rosin), under mild conditions (atmospheric pressure, 64 °C and 3.5 h) and without solvent. Other catalysts, such as magnesium oxide, titanium dioxide, and alumina, achieved up to 30% conversion. Calcium carbonate and calcium hydroxide were the main phases in the calcium-based material, suggesting that the strength of basic sites can be an important property of the catalyst activity. A calcium-based material was used in five reaction cycles, obtaining a significant reduction in the activity attributed to the leaching of some phases of the catalyst. [ABSTRACT FROM AUTHOR]

Background: The study of growth, development and productivity features of imported cattle from Australia to the Krasnodar Territory is of great scientific and practical interest, which is topical. Since the productive features of the imported genotypes have not been studied sufficiently, not only in the farms of the Krasnodar Territory but also in other regions of Russia, they require further, more in-depth study and improvement under the new conditions of feeding and housing. Aim: The research aimed to study the influence of intensive rearing of replacement heifers of the Holstein breed of Australian selection on cow milk quality indicators. Methods: The studies were conducted at Artex-Agro LLC, Kushchevsky District of the Krasnodar Territory, concerning the descendants of the imported Australian Holstein cattle. Sixty-four heifers were selected for the study. The experimental replacement heifers were raised using the enhanced milk feeding rates and the Cellobacterin probiotic product. They were raised intensively and inseminated when they were 14 months old. The milk productivity of cows and the physicochemical properties of milk were studied during three lactations after calving. Results and Discussion: The milk productivity of the cows from the experimental groups has exceeded one of their herd mates from the control group by 450 – 1,360 kg. The best indicators of the physicochemical properties of milk have been determined in the milk of the cows raised from the heifers fed with 450 kg of the whole milk during the first 50 days until they were six months old. Conclusions: The authors believe that intensive rearing of replacement heifers positively affected the degree of development of their gastrointestinal tract and improved the level of milk yield and its physicochemical parameters. [ABSTRACT FROM AUTHOR]

Este trabalho consiste na análise da distribuição espacial de foraminíferos como bioindicadores de stress ambiental e poluição em sedimentos superficiais do estuário Rio Potengi e plataforma adjacente. Foram coletadas 42 amostras nos anos de 2011 e 2012 e aplicadas análises estatísticas univariadas e multivariadas (diversidade, dominância, equitatividade, PCA, CLUSTER e BIOENV) sobre uma matriz de dados bióticos (foraminíferos bentônicos) e abióticos (profundidade, salinidade, temperatura, granulometria, matéria orgânica, CaCO3 ). O estuário é dominado por foraminíferos calcários hialinos (Ammonia tepida, Hanzawaia boueana) associados às frações arenosas finas, enquanto a plataforma interna é dominada por espécies porcelanáceas (Quinqueloculina lamarckiana, Q. miletti) e aglutinantes (Caronia exilis, Textularia earlandi), associadas à granulometria grossa. A presença de organismos mixohalinos (Caronia exilis e Trochammina spp.) na plataforma indicam contribuição estuarina na composição de sedimentos da plataforma e no transporte de efluentes de esgotos. A granulometria, CaCO3 , matéria orgânica, aportes fluviais e marinhos são os principais fatores que influenciam na distribuição dos foraminíferos. Espécies oportunistas (Ammonia tepida, Quinqueloculina patagonica) associadas às granulometria fina e elevados teores de matéria orgânica revelaram locais com poluição crítica dos sedimentos no interior do estuário, onde mantiveram-se constantes nos anos de 2011 e 2012.

No sistema plantio direto (SPD), a aplicação de calcário é feita sobre a superfície do solo e o tempo transcorrido desde a aplicação é importante para que as reações se processem. O objetivo deste trabalho foi avaliar, a longo prazo, os efeitos da aplicação superficial de calcário sobre alguns atributos químicos, ao longo do perfil de um solo originalmente ácido. Para isto, foram coletadas amostras de solo em sete camadas, até a profundidade de 60cm, 93 meses após a aplicação de doses de calcário dolomítico correspondentes a zero, 1/4, 1/3, 1/2 e 1 vez a necessidade para elevar o pH-H2O do solo a 6,0. O experimento foi conduzido sobre um Nitossolo Vermelho, sob SPD, em Campos Novos, SC. Os atributos avaliados foram pH-H2O, pH-KCl, H+Al, Al, Ca, Mg, Cu, Zn, Mn e Fe. A aplicação superficial de calcário aumentou, após 93 meses, o pH-H2O, pH-KCl, Ca e Mg trocáveis do solo e diminuiu os teores de H+Al, Al e Mn nas camadas superficiais. Não houve efeito do calcário nos teores de Zn, Cu e Fe. Os efeitos mais significativos das doses de calcário foram observados até 10cm para o pH-KCl, Ca e Mn; até 15cm para o pH-H2O e H+Al; até 20cm para o Al e até 40cm para o Mg.

Avaliou-se a fertilidade do solo em lavouras de quatro regiões de Santa Catarina, definidas pela similaridade de formação geológica e de clima, a partir de resultados de 35.163 amostras enviadas em 2004 aos laboratórios oficiais do Estado. O conteúdo de argila aumenta do leste para o oeste do Estado, seguindo o padrão de mudanças no material de origem. Nesse mesmo sentido, ocorre um aumento do número de amostras nas classes de maior teor de matéria orgânica. As classes de interpretação muito baixa e baixa de pH em água predominam em todas as regiões, mas grande parte das amostras apresenta teores de Ca e Mg trocáveis nas classes média ou alta. É significativo o número de amostras com saturação por bases muito baixa ou baixa e saturação por Al alta ou média, principalmente nas regiões litorâneas e com solos originados de rochas sedimentares. A maioria das amostras apresenta teores médios ou maiores de K extraível, exceto na região litorânea, e mais de 50% das amostras de solo apresentam teores médios ou inferiores de P extraível.

Six cold-pressed oil samples obtained from the seeds of different grape varieties grown in a Fruška Gora vineyard in the Republic of Serbia were examined for chemical and nutritive quality, as well as antiradical capacity. All the tested samples were of good quality, but the results showed noticeable differences in seed oil properties for red and white grape varieties. The highest content in total tocols, 575.23 ± 4.46 mg/kg, was found in the red grape seed oil of the Merlot variety, but the vitamin E activity of white grape seed oils was significantly higher. Regarding single phenols, the most prevalent fraction in all the oil samples was ursolic acid, up to 336.3 ± 4.8 µg/g in the grape seed oil of the Hamburg variety. The highest content in the total phenolic compounds, 54.92 ± 0.93 µg GAE/g, was detected in the oil of red grape seeds. Although significant differences existed between samples, EC50 values were the lowest for the red grape seed oils, varying from 29.84 ± 1.07 to 65.34 ± 0.32 mg oil/mg DPPH, indicating that these oils had the highest antiradical capacity. [ABSTRACT FROM AUTHOR]

Se evaluó la composición proximal, el contenido de polifenoles totales y la capacidad antioxidante de un chocolate oscuro formulado a partir de granos de cacao orgánico, seco, y no sometido al proceso fermentativo. Este producto fue elaborado con insumos y procesos desarrollados en la Granja Experimental El Cairo, ubicada en la Universidad Nacional de Colombia (GEL-UN), departamento de Arauca, Colombia. El contenido de grasa se encontró entre los rangos conocidos (>50%), siendo una característica ligada al origen genético, y a las condiciones climáticas. El alto contenido de proteínas (16,21%), evidencia que se trata de granos de cacao secos no fermentados. Tal contenido juega un papel importante en la formación de los precursores del sabor y aroma, en chocolates finos y exquisitos. El pH determinado es un indicativo de un chocolate amargo, con bajo índice de fermentación y de baja acidez acética o láctica. El contenido de polifenoles totales se relaciona de manera directa con la alta actividad antioxidante de este chocolate. Se concluye que el tipo de material genético usado como insumo, así como los procesos implementados para la obtención del chocolate, en GEL-UN, contribuyeron para la obtención de un producto tipo comercial, con propiedades funcionales, entre ellas las relacionadas con la capacidad antioxidante.

La apicultura en las regiones tropicales de México tiene antecedentes de cientos de años. Las abejas sociales y productoras de miel son parte esencial de las costumbres religiosas, alimenticias y comerciales de muchos pueblos indígenas. La miel para consumo humano debe tener buenas condiciones higiénicas, comportamiento microbiológico característico como consecuencia de la composición del producto base elaborado por las abejas. El conocimiento ancestral no se pierde, sin embargo el proceso de elaboración y envasado ha ido cambiando de acuerdo a las necesidades de los productores y consumidores. Sin embargo no se tiene registro de la forma de elaboración, se desconoce si el proceso de envasado es el correcto y si las características que dicho envase proporciona a la miel diferentes características físicoquímicas. Por lo anterior en esta investigación se realizaron encuestas a apicultores del Municipio de Tepatlaxco, para registrar los conocimientos que poseen en cuanto a la producción de miel. Se determinaron variables fisicoquímicas (pH, grados Brix y acidez) de la miel envasada en plástico, vidrio nuevo y vidrio reutilizado a diferentes tiempos de anaquel. Algunos de los resultados encontrados fueron que el envase de vidrio, nuevo y reciclado son opciones viables para los apicultores del municipio de Tepatlaxco, Veracruz ya que preserva las características particulares de la miel.

Copyright of Ingenium: Revista Electrónica de Pensamiento Moderno y Metodología en Historia de las Ideas is the property of Universidad Complutense de Madrid 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.)

A avaliação dos atributos sensoriais pode ser uma ferramenta importante para controlar e melhorar a qualidade de produtos alimentícios. Este trabalho teve como objetivo descrever sensorialmente amostras de café torrado e moído da espécie arábica de diferentes marcas brasileiras por teste descritivo avançado (projective mapping) e relacionar os dados obtidos com resultados físico-químicos. Foram analisados acidez titulável, pH, sólidos solúveis, cor, lipídeos, proteínas, compostos fenólicos, cafeína, trigonelina, ácido 5-cafeoilquínico e ácido caféico. Os resultados obtidos nas análises físico-químicas foram coerentes com os atributos relacionados aos cafés no projective mapping. Os cafés agrupados no projective mapping próximos ao atributo acidez foram os que apresentaram os maiores valores de ácido 5-cafeoilquínico. Os cafés associados ao sabor amargo/torrado e cor concentrada apresentaram cor mais escura na análise colorimétrica e características físico-químicas de torrefação escura. O café considerado bebida diluída foi o que apresentou menor valor de sólidos solúveis. Os resultados mostraram que o projective mapping é eficiente para análises sensoriais descritivas de café e que o público testado tem preferência por cafés tradicionais com torrefação escura.

El estudio realizado tuvo como principal objetivo medir el pH de cuatro muestras de suelo, tomadas de diferentes lugares, con el fin de determinar cuál de estas poseía las condiciones más óptimas para el crecimiento de una planta y así conocer con claridad cómo se ve afectado el crecimiento de las plantas según el nivel de acidez que presente el suelo al que esté sometida. Este estudio es de mucha importancia para algunas actividades del sector primario como lo son la agricultura, ganadería y silvicultura, puesto que es necesario en las plantaciones de vegetales, granos y legumbres, reforestaciones y todo lo relacionado con las especies productoras de oxígeno. El método con el que se llevó a cabo la medición del pH, se caracteriza por ser sencillo y casero, pues los materiales utilizados son de rápido acceso, por lo tanto se realizó más de una vez para obtener resultados mucho más precisos. Lo que incentivó a llevar a cabo este procedimiento, fue la búsqueda de respuestas a preguntas como: ¿por qué algunas plantas no crecen en algunos suelos y otros no? ¿a qué se refieren cuando dicen que una planta esta desnutrida o raquítica y cuál es el motivo de que este así? ¿qué tan acido o alcalino puede ser un suelo y cuáles son sus consecuencias?

Se evaluó la hidrogenación de limoneno hacia p-mentano en presencia de catalizadores Pd/Al2O3-SiO2. Para ello, se utilizó un reactor intermitente, el cual fue operado a diferentes temperaturas de reacción (75, 100, 125 y 150°C) y una presión de 200 psi de H2. Los resultados muestran que la presencia de sílice en el soporte catalítico, como es el caso de la zeolita ZSM5, favorece la transformación de limoneno hacia p-mentano debido a la presencia de un mayor número de sitios activos. Así, cuando se utilizó el catalizador Pd/HZSM5, se alcanzó un rendimiento de p-mentano del orden de 92% a 100°C, mientras que cuando se utilizaron los catalizadores Pd/Al2O3 y Pd/Al2O3-SiO2, el rendimiento de p-mentano fue inferior al 90%, incluso a una mayor temperatura de reacción (125°C).

Tropical soils are characterized by acidity and poor plant nutrient availability, limiting their agricultural productivity. These soils are commonly amended with lime, but its low solubility impairs its effectiveness to enhance soil fertility. The use of gypsum has gained attention among farmers due to its higher solubility and mobility in the soil, local accessibility, and low price. Therefore, this study was conducted to determine the effects of Agricultural Gypsum (AG) addition on ten Colombian acid soils that had poor fertility and contrasting their physical and chemical characteristics. Surface (0-20 cm) soil samples were air-dried, sieved (<2 mm), and transferred into plastic vases, 40 g (dry base) per vase. Increasing rates of gypsum were added by duplicate: 0.0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, and 16.0 g kg-1. Then, the soils were incubated for two weeks and watered to maintain 50% of their maximum water holding capacity. Soil pH, Al+3, Ca+2, Mg+2, K+, S-SO4 -2, and P-H2PO4 -2 were measured using standard methods. The results showed that AG addition significantly (P<0.05) increased soil exchangeable Ca+2-K+, Ca+2 saturation, S-SO4 -2 concentration, and exchangeable Al+3, particularly with doses above 4.0 g kg-1. In contrast, soil Al+3 saturation, P-H2PO4 -2 and pH significantly decreased as the AG doses increased, while soil exchangeable Mg+2 levels were not significantly affected. The use of gypsum incubation tests could be promissory for its effects on soil amelioration associated mainly to increase soil exchangeable Ca2+ and S-SO4 2- and to decrease Al3+ saturation. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the quality of the soil in Pilões, Paraiba's Brejo, where the cultivation of cashew is made this cultivation is related to the soil fertility and will be an element analyzed by this article. Through visits to the studying area, we selected an area of 5 ha, 12 years old and always clubbed together in the same space of other subsistence crop as such as beans, maize and cassava, and has never been chemically fertilized. Thus, four trenches where the soil samples were collected at depths 0-10, 10-20, 30-40, and 40-50 cm were opened. Each trench represents a repetition. These samples are determined according to EMBRAPA (1997) pH, phosphorus (P), potassium (K), Ca - Mg - Al, H + Al, Matt Org (MO) and SB= Sum of exchangeable bases, CTC (t) - Effective Cation Exchange Capacity, CTC (T) - Cation Exchange Capacity at pH 7,0, V= base saturation index, m= saturation index aluminium and P-rem= Remnant Phosphorus. [ABSTRACT FROM AUTHOR]

This research aims to analyze chemical aspects in vitro of the erosive potential for dental structure of energy drinks and its influence on nutrient absorption. The methodological bases used followed the internationally accepted standards for the analysis of hydrogen potential, total titratable acidity, total soluble solids and reducing sugars. The results obtained showed a line of products with high acidity, with averages between 2.89 to 3.55 in hydrogen potential. The levels for total titratable acidity ranged from 0.26 to 0.80 g of citric acid, with some significant differences between the samples. The contents of total soluble solids showed significant differences between all samples. The levels of reducing sugars showed averages that ranged from 26.42 to 131.65 g/L, with significant differences according to the Tukey test for p≤0.05. The data presented are worrisome, as the consequent changes in the dental structure affect the intake of important foods for the maintenance of health, which leads to inadequate micronutrient absorption rates. From these data, we conclude that there is a need for joint interprofessional action, with nutritionists, dentists and inspection bodies active in the continuous observance of food composition, with emphasis on industrialized beverages due to their action on the emergence of demineralization and enamel erosion, and the consequent reduction in the contribution of the consumption of essential regulatory nutrients to good nutrition. [ABSTRACT FROM AUTHOR]

Controlling the factors that influence the conservation of extruded dog foods can increase shelf life and/or guarantee the quality of shelf life of diets for these animals. Therefore, the objective was to evaluate the relationship among water activity (Aw), moisture (M), acidity, lipid peroxidation, crude protein (CP), ether extract (EE), and kibble size of extruded dog foods stored in sealed and open packages for 60 days (Experiment I). We also evaluated the stability of the Aw for up to 6.5 hours after coating with palatant (Experiment II). We manufactured four extruded dry dog foods: high CP and EE (HPE); low CP and EE (LPE); small kibble (SK); and large kibble (LK). In experiment I, the foods were stored in sealed 1 kg packages and 10 kg open packages, for a period of 60 days. We measured Aw, M, acidity, peroxide, CP, and EE of foods and the relative humidity (RH). Data were subjected to Pearson correlation analysis. For experiment II, samples were collected immediately after coating with palatant. Sub samples were collected every half hour to measure Aw. In experiment I, positive correlations were observed (P<0.05) among kibble size, M, and Aw; acidity, CP, EE, and M; and between Aw and RH, for open and sealed packages. There was also a positive correlation (P<0.05) for open packages among time, Aw, and peroxide. In experiment II, LK and LPE food presented Aw stabilized in less time. Diets with higher kibble size and high CP and EE levels are more unstable if kept in open packages. Extruded dry food with higher protein and lipid and smaller kibble size needs more time to stabilize its Aw. [ABSTRACT FROM AUTHOR]

Copyright of Revista Biológico Agropecuaria Tuxpan is the property of Revista Biologico Agropecuaria Tuxpan 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 los últimos 15 años se viene planteando en Cuba que el proceso de degradación de los suelos por acidificación ocurre con cierta intensidad. Se plantea que el 40% del territorio está afectado por este proceso y se pronostica que hay un incremento del mismo de 2,9% anualmente. Además, que con la erosión se acidifican los suelos. En este trabajo se demuestra que la acidificación por erosión solamente ocurre en Cuba en los suelos del Agrupamiento Alítico, ya que el horizonte B tiene un contenido alto en aluminio cambiable y pH igual o menor de 4,5. Pero estos suelos son poco extensivos en Cuba donde ocupan solamente 5% del territorio nacional. El principal objetivo lo constituye el demostrar que en los suelos del Agrupamiento Pardos Sialíticos (que son los más extensivos de Cuba, 21% del territorio), aumenta el pH en profundidad, por lo que cuando se erosionan no se acidifican, sino que aumenta el pH. Estos resultados demuestran que el proceso de acidificación tan intenso para los suelos de Cuba, como se plantea en algunos trabajos, no ocurre realmente. [ABSTRACT FROM AUTHOR]

Copyright of Engenharia na Agricultura is the property of Engenharia na Agricultura 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 Engenharia na Agricultura is the property of Engenharia na Agricultura 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 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.)

The aim of this study was to assess the influence of heat treatment on physicochemical and rheological characteristics of natural yogurts, as well as the influence of lyophilization process on natural yogurts after reconstitution. In the first experiment, three yogurt treatments were processed, as follows: Treatment 1, yogurt produced with raw refrigerated milk; Treatment 2, yogurt produced with refrigerated pasteurized milk; and Treatment 3, yogurt produced with UHT (ultra-high temperature) milk, in addition to analyses of fat, protein, moisture, titratable acidity, and pH. The shelf life of yogurts at 1, 8, 15, 22, and 29 days of storage, as well as pH, acidity, syneresis, viscosity, viable lactic bacteria, and total coliforms were also assessed. In the second experiment, yogurts were submitted to lyophilization process, performed by scanning electron microscopy analysis and subsequently in those reconstituted, in addition to being assessed the physicochemical, rheological, and viable lactic bacteria characteristics. The results found in the first experiment showed that heat treatment was positive for viscosity, syneresis, and lactic bacteria, being viable until the 15th day of storage only for yogurts submitted to heat treatment. In the second experiment, lyophilization preserved the physicochemical characteristics of yogurts, but the number of initial lactic bacteria was different, also negatively affecting yogurt viscosity.

El objetivo de la investigación consistió en realizar una selección y adaptación fenotípica de tres variedades élites de caña de azúcar (Saccharum officinarum L.) para la producción de panela granulada en la provincia de Bongará. Para ello, se eligió un factorial en DBCA, y el esquema seguido en campo fue mediante el uso de nueve variedades, entres diferentes edades de corte, y en cuatro bloques, formando un total de 27 tratamientos. De las variedades elegidas, tres fueron autóctonas de la zona, y seis introducidas del ámbito nacional e internacional. El área experimental fue instalada en el anexo de Cocachimba a una altitud de 1721 m.s.n.m. Las variedades evaluadas fueron Mex73-523, Amarilla (PR10-59), Carriza (POJ29-61), V74-7, Mex73-1240, Colcamar (CO-421), Mex79-431, H32-8560 y Mex69-290.Las variables que se tuvieron en cuenta para la selección y la administración de los tratamientos fueron: “rendimiento de grados brix(°Bx)”, “biomasa(Tn/Ha)”, y “rendimiento de jugo (Kg jugo / 100 Kg d ecaña)”. Se obtuvieron diferencias significativas entre las medias de los tratamientos, para los rendimientos de grados brix(p = 0,000 < 0,05), biomasa (p = 0,000 < 0,05), y jugo (p = 0,000 < 0,05), a través de pruebas de análisis de varianza (PruebaANOVA).