Revista LASALLISTA de Investigación
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Browsing Revista LASALLISTA de Investigación by Author "Acosta Otálvaro, Elly Vanesa"
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Item Determinación del potencial bactericida In vitro de un aislado nativo de Lactobacillus cassei frente E. coli(Corporación Universitaria Lasallista, 2008) Gutiérrez Ramírez, Luz Adriana; Acosta Otálvaro, Elly VanesaIntroduction. Probiotics are living microorganisms with a great capacity against other microorganisms, this is why there is an interest in using them as natural bio-preservatives, reducing partially the use of chemical preservatives in food. Objective. To determine the bactericide effect of the raw extract of native L. cassei on the in Vitro growth of pathogenic bacteria, such as E.coli. Materials and methods. The raw extract was obtained by cultivating the microorganism in 20 ml of MRS breeding ground at 37 ºC Turing 72 h, anaerobically. The experiments were done in three periods of time: 5, 10 and 15 days. The method used to detect the activity of the extract was the experiment of diffusion in wells. Those that represented an inhibition halo above 2mm were considered as active. The results found were compared with those from a strain of Lactobacillus plantarum of for commercial use with a bactericide activity against Escherichia coli. Results. L.cassei represented hostile activity against E.coli, because the inhibition zones read as response variable were higher than 2mm until getting the 10-3 dilution in the three experiments made. However, on day 15 the bactericide activity of the extract was considerably reduced when compared to that from day 5. The analysis of activity units showed that the extract from this isolated is active even in high dilutions, which means that the extracts are active even at very low concentrations. Conclusion. The native isolated of L.cassei produces antimicrobials against Gram negative bacteria, such as E.coli, being available for their possible use as natural bio preservatives in food.Item Sustitución de tartrazina por betacaroteno en la elaboración de bebidas no alcohólicas(Corporación Universitaria Lasallista, 2006) Restrepo Gallego, Mauricio; Acosta Otálvaro, Elly Vanesa; Ocampo Peláez, Juan Camilo; Morales Monsalve, CristianIntroduction. Colorants, as alimentary additives are currently under observation because their possible effects on the consumer’s health. Therefore, studies are being made in order to substitute artificial dyes for others with a natural origin. Among these, tartrazine is one of the few aditives that must be declared out of the list because of its possible allergenic effects. As an alternative of substitution, we have beta carotene, because of its natural origin and its anti oxidant properties. Objective. To evaluate the feasibility of replacing tartrazine with beta carotene as yellow dye to elaborate a not alcoholic beverage. Material sand methods. The work was made with tartrazine and commercial beta carotene and calibration curves were made by the use of UVvisible spectrophotometry for both dyes. Then, a follow up of the compounds´ stability was made under different environmental conditions in order to determine their degradation. Finally, a sensitivity evaluation of the product was made to identify possible adverse effects on the taste of the beverage. Results. Under extreme environmental conditions (sudden temperature changes and direct sunlight) tartrazine is more resistant than beta carotene. Nevertheless, under normal storage conditions (interior, refrigeration boxes) both dyes show an adequate stability. The sensitivity evaluation resulted in a 64% preference of those evaluated for the product with beta carotene because of its more natural appearance and better texture and taste. Conclusion. Betacarotene can be used as a substitute for tartrazine in the fabrication of not alcoholic beverages, but storage conditions must be adequate.