Química

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https://usc.scimago.es/handle/20.500.12421/91

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Diseño, implementación y mejoramiento de un método para la disminución del desperdicio generado durante el empaque y embalaje de harina precocida de maíz en la empresa alimentos del Cauca S.A.
(Universidad Santiago de Cali, 2012) Valderrama González, Luis Alfonso; Garzón Garcia, Guillermo
Using statistical process control as a tool for improvement, improved packaging process, integrating teams and encouraging the participation of the same. The application of this method of analysis of a representative sample packs precooked cornmeal able to reduce wastage of the same. This involved the development of technical and administrative skills to solve problems. It also encouraged the participation of the company's operating personnel. Developing this project has managed to launch the appropriate methodology to the particular case, facilitating the organization of control instruments for proper resource management plan.
Caracterización fisicoquímica funcional del Almidón extraído de la papa china (Colocasia Esculenta) cultivada en el pacífico colombiano
(Universidad Santiago de Cali, 2019) Hurtado Herrera, Janer Guillermo; Castillo Ayala, Jorge Enrique
The evaluation of the physicochemical and functional properties of the starch extracted from the Chinese potato tubers (Colocasia esculenta) from the municipality of Timbiquí and López de micay – Cauca was carried out. The granules had particle size around (3.5-7.8 µm in diameter for sample 1 and 3.5-7.0 µm in diameter for sample 2); a high content of % amylose (67.6 and 70.7 respectively for M1 and M2) was found compared to other botanical sources, through the colorimetric method recommended by ISO 6647. The gelatinization temperatures were (78, 6 and 81.9 ° C, respectively) by heating a solution of the starch until a stable paste formed for a few seconds. The samples showed low water solubility (0.13 M1 and 0.23 M2 g / 100 mL) and a high water retention capacity (280.3 and 391.7% at 60 ° C) compared to 226% of the cassava and 162.8% for sago: which makes it a good quality starch. The gel pastes when subjected to a % processing of light at 650 nm in a Thermo Evo 201 UV spectrophotometer was (3.4 and 4.1%) respectively. Comparing these characteristics found in this tuber with other sources of starch commonly used in the industry, it is concluded that it can be used as a promising alternative in the food industry; In addition to having a high amylose content, it is a resistant starch, providing physiological health benefits.
Diseño, síntesis y actividad biológica de péptidos antimicrobianos catiónicos
(Universidad Santiago de Cali, 2019) Vargas Carabalí, Lina Fernanda; Oñate Garzon, Lina Fernanda
Antibacterial resistance to conventional antibiotics is an emerging problem worldwide. This urge to develop alternative antibiotics has motivated researchers to look for new molecules to overcome this resistance problem, such as antimicrobial peptides (PAMs). PAMs are important effector molecules of the innate immune system, which is the main defense mechanism for most living organisms. Alyteserin 1c, is an antimicrobial peptide secreted in the skin of the toad Alytes obstetricans characterized by having a net charge +2 (WT). Based on the WT peptide, an analogue (ΔM) was developed, which presents a +5 net charge as a result of different amino acid substitutions in the polar face of the Alyteserin 1c helix. Both peptides were synthesized using the solid phase peptide synthesis method. The yield of the unpurified synthesis was 29.7% for each peptide. After the process of purification by reverse phase high efficiency liquid chromatography, the yield was 4.95% for the WT and 13.2% for the ΔM. Subsequently, the purity of the peptides was verified using the Bruker Daltonics MALDI-TOF mass spectrophotometer, which was 95% in both peptides. Regarding the antibacterial activity, the WT peptide exhibited a minimum inhibitory concentration (MIC) of 62.5 μM and 250 μM, against the bacteria Staphylococcus aureus and Salmonella typhimuriom, respectively, on the other hand, with the ΔM MICs were obtained from 125 μM and 62.5 μM, for both strains respectively. Regarding the hemolytic activity of the peptide WT and ΔM, it was observed that the minimum hemolytic concentration is 62.5 μM in each one.
Evaluación de las propiedades fisicoquímicas del almidón termoplástico en presencia de ácido láctico
(Universidad Santiago de Cali, 2019) Pastrana Gutiérrez, Isabel
The thermoplastic starch was modified with lactic acid in the molten state, using two types of starches (achira and potato) and two different plasticizers, glycerol and sorbitol. These components were used in a 70:30 ratio (starch: plasticizer) and the addition of acidic agent was carried out in portions of 3, 6 and 9% by weight. These mixtures were obtained in a torque rheometer at 130 ° C for 10 min. The thermal characterization performed showed greater stability for the samples of TPSL> TPS, the values in the temperature of degradation varied between 230 ° C to 280 ° C, while for the thermal transitions corresponding to the temperature of gelatinization and fusion they showed a decrease in the crystallinity for the samples with 6% oleic acid, these results were consistent with the morphological analysis. The results derived from the oscillatory rheological analysis had a viscous behavior in the TPS samples, while the presence of the acid generated viscous to elastic transitions. Finally, a reduction in the hydrophilicity of the modified TPS was evidenced because some of the samples increased the value of the contact angle by up to ~ 46%.
Estudio de las interacciones del péptido Alyteserin 1C y de su análogo catiónico con modelos de membranas
(2019) Sanchez Arias; Kevin; Oñate Garzón; José Fernando
Antimicrobial peptides are part of the innate immunity of most living things and have antimicrobial activity against bacterium, viruses, fungi and parasites. Their cationic characteristics make them selective towards bacterial membranes with anionic surfaces.
Polímeros de coordinación de plata(I), cobalto(II) y manganeso(II) con PVA inmovilizado en quitosano depositado en aluminio y vidrio erosionado
(Universidad Santiago de Cali, 2019) Díaz Canchimbo, Viviana Maria; Avila Torres, Yenny Patricia
The aim of this research work was the development of low and medium molecular weight chitosan (Q) membranes embedded with polyvinyl alcohol, which were enriched with the metal ions of: copper (II), cobalt (II), manganese ( II) and silver (I) as new bactericidal materials. The method used was electrospinning, establishing optimal deposit conditions (DC 11 cm, VB 0.01 mL / hr, V 16 Kv, T 70 min and 16% PVA) on two aluminum surfaces and eroded glass. The antibacterial activity was carried out against Staphylococcus aureus and Eschericia Coli by comparing the activity in solution and its corresponding supported membrane. The method used was Kirby - Bauer modified discs, implementing as positive controls amoxicillin at 25000 ppm and the metal salts at 50000 ppm by each transition metals. The preliminary results show bactericidal and bacteriostatic activity mediated by the nature of the metal ion, further studies are proposed in order to understand the diffusion process and the effect on the stability of the coordination polymers with respect to biological activity.
Estudio estructural y supramolecular por medio de difraccion de rayos x y superficies de hirshfeld del compuesto ácido 2-(e)-((4-hidroxifenil) diazenil) benzoico
(Universidad Santiago de Cali, 2019) García Carreño, Camila Andrea; D´Vries Arturo, Richard Fernando
The crystalline structure of 2-(E)-((4-hydroxyphenyl) diazenil) benzoic acid compound, was resolved by means of the intrinsic phase method using single-crystal X-ray diffraction data. It was find that the molecule crystallizes in the ortorombic crystalline system with Pbca space group. Within its unit cell there are four molecules per asymmetric unit, which are molecular conformers and form beta helix arrangement along [0 1 0] direction. Hirshfeld surface calculation was performed to determine the intermolecular interactions that contribute the most to crystalline packaging. It was possible to observe that the main contribution to the general surface is given by the contacts H…H (34.8%), followed by interactions O…H/H…O (27%) and C…H/H…C (18.6%). The energy interaction networks were calculated at a HF/3-2 level, allowing to quantify the high participation of dispersion interactions (-57.5 kJ/mol) in the formation of crystalline packaging. Keywords: crystallography, Hirshfeld surfaces, X ray, cell unit, intrinsic phase
Diseño de un sistema de gestión ambiental para la empresa Análisis Ambiental S.A.S., basado en la norma NTC 14001: 2015
(Universidad Santiago de Cali, 2019) Mosquera Mosquera, Gloria Stephanía; Angulo Piñeros, Nathalia; Garzón García, Guillermo; Robles Pardo, Edilberto
La empresa ANALISIS AMBIENTAL S.A.S. presta servicios de Ingeniería Ambiental y Sanitaria que incluyen asesorías en plantas de tratamiento de aguas, monitoreos en agua, aire y suelos; como también servicios de análisis de Laboratorio fisicoquímicos y microbiológicos. Estos servicios generan impactos sobre el medio ambiente, y siendo conscientes de ello, se ha diseñado un Sistema de Gestión Ambiental basado en la Norma NTC - ISO 14001 de 2015 para conocer su naturaleza, y de esa forma mitigar y/o controlarlos de manera efectiva.
Generación de carbón activado a partir del residuo de cosecha de Ananas comosus para la remoción de metales pesados Plomo (Pb+2) y Cadmio (Cd+2)
(Universidad Santiago de Cali, 2019) Nidia Marcela Velásquez Varón; Zambrano Salgado, Yesid Fabián
In this study, activated charcoal was prepared from the leaves of Ananas comosus; by chemical activation, from two different pyrolysis temperatures (500 ° C and 600 ° C) and different concentrations of activating agent (20%, 40%,42,5% and 60%) in a 6: 1 impregnation ratio, with which yield percentages were obtained which varied from 47.15% to 54.82%. The surface chemistry of the coals was studied by FTIR infrared spectroscopy. The adsorbent properties of heavy metals (Pb2 + and Cd2 +) were measured from aqueous solutions, obtaining a removal percentage above 80% for both solutions. The adsorption isotherm was performed, in which the linearized experimental data fit very well to the Langmuir adsorption isotherm model, where the chemotherapy of lead and cadmium heavy metals is produced from the aqueous solutions.
Cuantificación por HPLC de Trans-resveratrol en la uva Isabella (vitis labrusca) cultivadas en la Unión-Valle del Cauca
(Universidad Santiago de Cali, 2019) Ospina Ramírez, Stephanie; Castillo Ayala, Jorge Enrique
The Isabella grape (Vitis labrusca) is a variety that has been optimally adapted to the climatic conditions of La Unión-Valle del Cauca, and has had good acceptance in local markets. Currently the grape is consumed fresh and its phenolic content is unknown. According to epidemiological studies, the presence of bioactive compounds with antioxidant capacity such as trans-resveratrol, can exert a protective effect against some diseases such as cancer and cardiovascular disorders. For this reason, with this work the quantification of the trans-resveratrol present in the epicarp of the Isabella grape (Vitis labrusca) grown in La Unión-Valle del Cauca is performed, using high efficiency liquid chromatography (HPLC) with ultraviolet detector. It will ensure that the method to follow complies with the evaluation parameters (linearity, precision and accuracy). It is also intended to contribute to a methodological proposal for the extraction (liquid-liquid with acidified methanol) and purification of trans-resveratrol.
Desarrollo de dos antiespumantes en Disproquin S.A.S con aplicación en el proceso de producción de papel
(Universidad Santiago de Cali, 2019) Rojas Daza, Andrés Felipe; Floréz López, Edwin
In the paper industry the generation of foam is an important factor because it causes the paper to get porous structures affecting its quality. On the other hand, antifoam products are very effective in suppressing the foam generated in different processes. For this reason, two hydrocarbon and silicone-based antifoams were developed. For their characterization, physicochemical parameters such as pH, percentage of total solids, viscosity, particle size and density were determined. Fourier Transform Infrared Spectroscopy (FTIR), one of the components of the hydrocarbon-based antifoam, was also used. An experimental design was used to compare the efficiency of the hydrocarbon-based antifoam with a commercial antifoam followed by an efficiency study of the silicone-based antifoam. Finally, it was demonstrated that the hydrocarbon-based antifoam is more efficient as an antifoam and defoamer than the commercial product. Consequently, the silicone-based antifoam compound showed high efficiency at a temperature between 70 and 90 °C and a pH between 8 and 11. All these results show that these products could be used in different types of industries
Aplicación de la ecuación de Schrödinger en el estudio del movimiento de moléculas diatómicas
(Universidad Santiago de Cali, 2019) Bueno Barbosa, Douglas Andrés; Parada Valencia, Alexander
Understanding the physiochemical phenomenon at the subatomic level is very important in order to know the behaviour of the matter these energy scales. It is necessary to use the Schrödinger equation in the order to describe chemical and physically the molecules. Throughout of the development of this work, we addressed the study of the Schrödinger equation and applications in the movement of diatomic molecules. The interaction potential is described by this equation, as well as the translational, rotational and vibrational energies of each molecule. Likewise, the Hamiltonian is studied in a general way, and particularly for the hydrogen molecule. We learned the main knowledge relating with Quantum Chemical and after that we focus in the study of some diatomic molecules no studied in the literature until now. Then, a phenomenological study was carried out for the BrCl molecule.
Determinación de la Biodisponibilidad in vitro de hierro en diferentes matrices alimentarias elaboradas a partir de harinas fortificadas comerciales
(Universidad Santiago de Cali, 2019) Guzmán Aristizabal, Luisa María; Usuriaga Moreno, María Camila; Ramírez Navas, Juan Sebastian
Iron (Fe) deficiency has been recognized with the World Health Organization as a public health problem, in countries such as Colombia. It affects a large part of the inhabitants, especially children and women in gestation. In order to counteract the consequences generated by this population, the lack of this mineral establishes the need to use Iron Fortification. The aim of this work was to evaluate the effect of temperature on the iron diazability of three homemade preparations, in which commercial flours fortified with iron were used. The percentage dialysotity of Iron (Fe) was taken as an indicator of the bioavailability of said ore. The determination was made using the in vitro method, which includes an enzymatic digestion that simulates the physiological process under controlled pH conditions and subsequent quantification by atomic absorption spectroscopy. For each of the samples an estimated percentage between 4 and 5% was obtained which are according to the literature in that they do not exceed 10% absorption of non-hemine iron from food.
Modificación de superficies de carbono por reducción electroquímica de 1,10-Fenantrolina en medio ácido para la remediación de aguas contaminadas con plomo y mercurio
(Universidad Santiago de Cali, 2019) Crespo Martínez, Gloria Amparo; D´vries Arturo, Richard; Péttry Valencia, Drochss
Mediante la técnica electroquímica de voltamperometría cíclica, se modificaron superficies de carbono con películas de 1,10-fenantrolina para la electrorremediación de aguas contaminadas. Para esto, se realizó la reducción electroquímica de 1,10-fenantrolina en medio ácido sobre electrodos de carbono (carbón vítreo y minas de lápiz). Posteriormente, la modificación de las superficie fue comprobada por la oxidación electroquímica de las superficies, en un blanco de ácido sulfúrico 0.100 mol L–1, mostrando dos picos de oxidación electroquímica a 0.48 y 0.80 V vs Ag/AgCl, que evidencian la modificación de las superficies. Los resultados comparados con literatura permiten afirmar que ocurre la pasivación de la superficie con moléculas de 1,10-fenantrolina. El grado de modificación es dependiente del número de ciclos voltamperométricos realizados y para garantizar la modificación completa de las superficies de carbono, se realizó la reducción electroquímica de las superficies en una solución de 1,10-fenantrolina en medio acido, por 15 ciclos de barridos voltamperométricos. Estas superficies modificadas fueron utilizadas para la electrorremediación de soluciones que contienen plomo y mercurio con concentraciones conocidas. Se optimizaron parámetros como pH y potencial de deposición para la electroremediación utilizando cronoamperometría de doble pulso de potencial por 800 s, encontrando que el mejor potencial de deposición es -0,700 V vs Ag/AgCl y el rango de pH óptimo de trabajo está entre 3.00 y 5.00 para la remediación. Finalmente, la espectroscopia de absorción atómica determinó que la cantidad de plomo eliminada fue del 41.55% y 40.91%, cuando se estudió el efecto de potencial y pH, respectivamente. En la electrorremediación del mercurio, se eliminó el 22.42% cuando se evalúo el efecto de potencial y en el estudio del efecto de pH se alcanzó una eliminación del 53.87%. Las superficies aquí generadas pueden ser utilizadas para la remediación de ríos contaminados con metales pesados.
Calificación de un dispositivo de inmersión para así realizar recubrimientos de TiO2/Hidroxiapatita sobre superficies metálicas
(Universidad Santiago de Cali, 2019) Martínez Bellaiza, Daniela; Morales Morales, Jimmy Alexander; Castillo Ayala, Jorge Enrique
El método de inmersión o “Dip-Coating” es utilizado para la obtención de películas delgadas sobre diferentes superficies y con un amplio rango de aplicación; este consiste en la inmersión y posterior extracción de un sustrato dentro de una solución precursora para la formación de la película. En este trabajo se realizó la calificación de un dispositivo de inmersión de bajo costo elaborado en la Universidad Santiago de Cali y se ejecutaron recubrimientos sobre sustratos de acero inoxidable con TiO2/Hidroxiapatita por la técnica de química húmeda. Para la calificación se evaluaron parámetros de velocidad y tiempo de inmersión, abordando la calificación de instalación, desempeño y diseño (IQ, PQ y QD respectivamente); la síntesis de Hidroxiapatita se realizó por precipitación controlada y se analizaron las muestras secas por IR/ATR y TGA-DSC obteniendo unos picos característicos del compuesto y un buen comportamiento térmico, además se analizaron los revestimientos realizados utilizando técnicas espectroscópicas obteniendo los depósitos esperados en los sustratos y obteniendo una relación de Ca/P de 1,57.
Degradación de Ampicilina, Catecol y el colorante naranja II, a partir de residuos de CdS obtenidos de prácticas convencionales de química inorgánica
(Universidad Santiago de Cali, 2019) Vidal Ruíz, Victor Alfonso; Avila Torres, Yenny
The elimination of orange dye, catechol and ampicillin (products present in waste from practical work of organic chemistry and biochemistry), was carried out with cadmium sulfide (CdS). This inorganic material was obtained from of residues of acid- base Pearson's practices in the laboratories of inorganic and analytical chemistry. Cadmium sulfide is a semiconductor with a GAP 2.4-2.6 ; which allows its use as a photocatalyst in the visible region and enhances its application in the degradation of organic matter. An important source of this type of materials are the conventional practices at the laboratory level, where it is possible to obtain residues such as PbS and CdS; which are generally underutilized. In this article, the impure CdS residue was purified and characterized as was reported, previously. Subsequently, organic labs and has obtained the best parameters at pH neutral for the elimination of orange II. This behavior was compared with the transformation of catechol and ampicillin as neutral and zwitterion molecules. H2O2, KI and acetonitrile as solvent, were added in to order to evaluate synergistic effects and establish the role of the semiconductor, (huecos) h+ and OH-. This work is a contribution to the reuse of waste in teaching laboratories, which promote the recirculation water contaminated with this type of organic compounds and allows for the student to design experimental protocols that allow him to use two types of organic and inorganic waste.
Análisis estructural y supramolecular del compuesto (e)-3',6'-dihidroxi-2-((pyridina-2-yl metileno) amino) spiro[isoidolina-1,9'-xanteno]-3-ona
(Universidad Santiago de Cali, 2019) Cardona Restrepo, Camila; Fernando D¨vries, Richard
The crystalline structure of the compound (E) -3 ',6'-dihydroxy-2-((pyridine-2-and methylene) amino) spiro [iso-idoline-1,9'-xanthene] -3-one was solved and refined, using single crystal X-ray diffraction data. It was found that the compound crystallized in the triclinic P-1 space group. its unit cell present two molecules per asymmetric unit, which correspond to molecular conformers. Moreover, an analysis to determine the intermolecular interactions from the crystalline system was performed. It was observed that the crystal packing is formed mainly by hydrogen interactions type O-H••• N, and C-H•••O. Finally, the supramolecular interactions of the dimer were quantified using fingerprint plots, obtaining values of 41.4%, 12.9%, 11.1% and 10.4% for interactions type H•••H, C•••H, O•••H, H•••C respectively. The aforementioned diagrams were compared with the obtained for structurally similar molecules; their forms confirmed the differences at the supramolecular level of the compounds analyzed. With this project, it was possible to determine the structural and supramolecular characteristics of the compound. In addition, were acquired the basic concepts related to crystallography and supramolecular chemistry, both at a theoretical and experimental level.
Correlación instrumental y sensorial de la calidad de una muestra de yogurt de la empresa fructilacteos
(Universidad Santiago de Cali, 2019) Giraldo, María, Camila Erazo; Ramírez Navas, Juan Sebastián
Greek yogurt samples from the company fructilácteos of campo were sensorially characterized by a semi-trained panel. Likewise, a study of the physical-chemical parameters of the same was carried out. The objective was to correlate the sensory parameters with the instrumental ones (viscosity, syneresis, pH, acidity, soluble and total solids) to identify the instrumental parameters that approximate the sensations experienced when consuming fructilácteos Greek yogurt (YGF). On the sensory side of the panelists, there was a preference for YGF for its attribute of creaminess and acidity, while on the part of the consumer a preference of 58% was observed by the YGC, mostly male consumers, however in the instrumental parameters it is revealed that most of them enter the established limit, minus the parameter of viscosity, which was 1.02.
Evaluación de la aceptación y preferencia sensorial de dos variedades de helados comerciales sabor a chocolate
(Universidad Santiago de Cali, 2019) Cifuentes Rua, Roberto Miguel; Vera Pérez, Orley Aldemar; Ramírez Navas, Juan Sebastián
Two types of chocolate ice cream (Traditional and Light) were sensory characterized in three different and competitive brands of the market by means of two consumer-oriented tests (preference and acceptance), likewise, it carried out a study based on the physicochemical analyzes performed to these, to identify and explain the preference of an ice cream in particular, thus creating a database that will determine a good quality ice cream with good acceptance and competitiveness in the market. The results that had a greater preference for consumers for traditional ice cream 358 with 42.5% and for light 271 with 47.5%, additional it was concluded that additional additives to the composition such as chocolate sauce and stevia mix - Vanilla enhance the sensory parameters and certificates better acceptance, Friedman's test notes that ice cream does not differ significantly from each other in the different attributes evaluated, but preference inclinations by consumers are included.
“Epoxidación de los terpenos d-limoneno y β-pineno con participación de los reactivos comerciales tetraacetiletilendiamina (taed) y peroxicarbonato de sodio (pcs)”
(Universidad Santiago de Cali, 2020) Cuellar Lopera, Juan David; Delgado Millán, Roberto Andrés; Flórez López, Edwin; Franco, Jaime Martín
The epoxidation of D-limonene and b-pinene was successfully carried out using peroxyacetic acid produced in situ in a two-phase dichloromethane and water system, from the commercial reagents tetraacetylethylenediamine (TAED) and sodium peroxycarbonate (PCS) with sodium bicarbonate. The progress of the reaction was evaluated by thin layer chromatography (CCD) and separation by flash column chromatography (CCF), using silica gel 230- 400 mesh. The TAED used in this study was previously purified by recrystallization, with a yield of 80%. The epoxides obtained were analyzed by nuclear magnetic resonance and mass spectrometry and the yields were 72% for D-limonene and 75% for -pinene epoxides.

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