vol. 1 (2007)

El comportamiento reológico del mucílago obtenido de las cortezas de cadillo fue estudiado en función de la concentración a la cual se preparó la disolución y de las temperaturas a las cuales se encuentran los jugos de caña en el momento de la aplicación de los aglutinantes. Para la evaluación de las disoluciones se empleó un viscosímetro rotacional Brookfield DV II. Se usó el modelo de la ley de la potencia para describir el comportamiento de los valores de la velocidad de cizalla y del esfuerzo cortante, además para determinar el índice de consistencia (K) y el índice de flujo (n). La disolución mucilaginosa de cadillo preparado en jugo de caña exhibió un comportamiento pseudoplástico con n<1. Los resultados obtenidos en el estudio permiten determinar, con una confiabilidad del 95%, que la disolución mucilaginosa de cadillo pierde sus características aglutinantes en la medida en que se somete a la acción de la temperatura, siendo más susceptibles las disoluciones preparadas a concentraciones bajas. Se obtuvieron modelos matemáticos que describen el comportamiento reológico y la viscosidad aparente de la disolución mucilaginosa de cadillo en función de la concentración y de la temperatura.

The aim of this work was to study the effect of the oil proportion, flavour proportion, emulsifier proportion and emulsification pressure on the emulsificated flavor rheological behaviour, using a concentric cylinders viscometer. The experimental design was a 1/2 fractionated factorial, with two levels for each variable and four assays in the central point, to estimate the experimental error; the total number of assays and different formulations was twelve. The answer variables were the consistence index and the fluidity index of the potency law. The rhelogical measurements were good correlationated by the selected model; the fluidity values less than one demonstrated a pseudoplastic behaviour of the emulsions. Additionally accelerated stability proves were performed to 50ºC with centrifugation of the emulsions. The low oil content formulations were steady. A comparative sensorial analysis was realilzed to the steady flavours with samples to 20ºC, they do not showed perceptible differences.

El impacto de la ciencia en la industria moderna es tan impresionante que cuesta creer que no siempre fue así. No obstante, antes del siglo XIX, ciencia y tecnología fueron dominios separados, orientados por personas distintas y con objetivos diferentes. La primera de ellas, no generaba hallazgos que tuvieran uso inmediato en la industria, razón por la cual un descubrimiento científico podía esperar una o dos generaciones antes de ser aplicado prácticamente; la segunda, era más el resultado de esfuerzos individuales que de un proceso sistemático, llevando a las industrias a progresar técnicamente sin mayor relación con la ciencia de la época. Casi todos los primeros inventos no los hicieron hombres de ciencia (quienes estaban más preocupados por comprender los fenóme nos naturales) sino gente que vio la oportunidad de hacer algo relacionado con un problema existente. Ésta situación comenzó a cambiar radicalmente con el nacimiento y desarrollo de las industrias química y electrónica, las cuales necesitaron conocimientos tanto científicos como tecnológicos, e  hicieron que la producción de tecnología dejara de ser aleatoria para pasar a ser un esfuerzo organizado denominado investigación y desarrollo (I & D), cuya meta es la creación, programación y aplicación de conocimientos científicos (Schnarch, 1989), donde los avances tecnológicos se presentan como respuesta a problemas generados por innovaciones anteriores y cambios en la organización del trabajo o evolución del proceso productivo

Foods that contain pro and pre-biotic denominate symbiotic, these benefit the health maintaining the balance from the intestinal flora, reducing to the bad absorption of the lactose, increasing the protection against intestinal infections, among others. The probiotic and pre-biotic are functional products and nutraceutics, first they are defined as "alive micro organisms with capacity to improve the intestinal microbial balance producing beneficial effects for the health of the individual" and the pre-biotic are non digestible nutritional ingredients and that selectively favour the growth of beneficial bacteria. The nourishing ingredients that fulfil the requirements of pre biotic, until the moment, are the oligosaccharides ones. Pro biotic bacteria present/display sites of different action in the digestive system (Lactobacillus acts in the thin intestine, whereas bifid bacteria acts in the heavy intestine). The re-introduction of these microbial groups in the lodging is done by means of the administration of selected species, which will have to be in high and viable numbers at the moment of their consumption. Some technical aspects are common in the production of any type of milk or fermented drink, as they are: (i) type of organisms that constitute the culture to starter, (ii) temperature, oxygen presence and period of incubation, (iii) the proportion of inoculo, (IV) the production of starter, and, (v) the growth factors.

The palm oil bleaching is an important operation in the refinement in which usually appears inconvenient, although the company’s processors have developed technical to control the quality of the crude oil and to conduct the operation easier of bleaching, isconsidered unstable due to the variables that are handled. During the bleaching is retires of the oil soap plans, metals, phospholipids and substances that contribute colour, by means of the clay action launderers, who have pores and great superficial area, where the polluting agents are absorbed by physical effect, giving to purity and quality to the processed oil. In the national market are several clay marks; therefore arose the interest to determine that clay launderer displays better results in yield, removal of polluting agents and good properties to the refined oil. With the analyzed information of the experimentation, the incidences of each variable was evaluated and were the best conditions of agreed operation to the theoretical information and the experimentalresults that are presented in this article. In Colombia the Tonsil marks are in great proportion (Sud Chemie) with 35%, Pure Flow (Oil Dri) with 50% and Filtrol (Engelhard) with 15% of the market. Other marks are not due to their lack of competitiveness in price.

With the objective to study the effect of the difference of potential in the rheological parameters, the study of the rheology behaviour of a liquor “sabajón” was made, submissive a difference of potential between 11 volts and 45 volts in 11 applications with a rank of time between 120 second and 630 seconds. In order to determine the meaning of the results and of finding mathematical the models suitable that they give answer to the correlation of the variables, multiple regression analysis for each one of the dependent variables with respect to the independent ones was made. The drink “sabajón” is a slightly pseudoplastic fluid, with flow number average of 0.815 and to the being submissive different voltages and times from application, this index diminished up to 0.754, becoming more pseudoplastic the flow number, n, diminishes with the application of voltage from 0.815 to 0.754, which allows to conclude that the pseudoplasticity of liquor “sabajon” increases slightly with the electrical treatment. The index of consistency, k, increases with the application of voltage from 0.112 to 0.155, allowing to infer that the viscosity of the fluid (sabajon) increases due to better molecular ordering of the treated sample.

The software Numericals is a tutorial for support to the learning of the techniques used for the Numerical Analysis mediates the programming of the main numerical methods, for the solution of engineering problems. The numerical methods are technical by means of which it is possible to formulate mathematical problems of such form which they can be solved using arithmetical operations. Although there are many types of numerical methods, share a common characteristic: invariantly a great number of tedious arithmetic calculations are due to make. With the development of efficient and fast digital computers, the paper of the numerical calculates in the solution of engineering problems has increased in considerable form in the last years. Besides to provide an increase in the power of calculation, the general availability of the computers and its association with the numerical methods it has influenced of very significant way in the process of the solution of engineering problems.

The controlled atmosphere technology (AC) is used in cold quarters for the storage, or in containers for the transport, of vegetables and fruits products. This technique stabilizes the atmosphere that surrounds the product in precise percentage with relation to the present O2 and CO2 in her, depending on the vegetal variety to control. For the avocado (American Persea) like climacterical fruit and concretely for the Hass variety, product of world-wide export, the conservation in AC is innovating for the maintenance of its optimal quality.