Physical-chemical properties and microstructural characterization of traditional mexican chili (Capsicum annuum L.) powders.

Es un artículo científico publicado en la revista Agro Productividad, la cual se encuentra indizada en CONACyT, LATINDEXThe chili (Capsicum annuum L.) (Solanaceae) is native of America, is consumed as vegetable, spice, and as source of vitamins A, C and E, carotenoids, and capsaicin which produce the characteristic pungency of Capsicum species. The chili in Mexico is usually processed in dried form to conserve its color and flavor. The main objective of this work was to evaluate the physical-chemical properties and characterize the microstructure of four varieties of traditional Mexican chili (Capsicum annuum L.) powders: “Arbol”, “Guajillo”, “Piquin” and “Mole ranchero” (Ancho chili). Physical-chemical properties of chili powders were evaluated by means of moisture content, particle size, aerated and tapped bulk density, Carr index, Hausner ratio, angle of repose (flow properties), capsaicin, and carotenoids content. Microstructure of samples was characterized by Confocal Laser Scanning Microscopy and Scanning Electron Microscopy. ANOVA analysis and Tukey test were performed to evaluate the significant statistical difference between samples at 95% of confidence level. “Arbol”, “Guajillo”, “Piquin” and “Mole Ranchero” chili powders presented a cohesive behavior respect to its flow properties related to aerated and tapped bulk density, angle of repose, Carr Index, and Hausner ratio values under moisture content between 6.59-14.48 g H2O/100g d.s. “Arbol” and “Piquin” chili powders presented the higher capsaicin content, while “Guajillo” and “Mole ranchero” showed the higher carotenoids content. FTIR spectra confirmed the presence of secondary amide, phenolic groups, alkanes, and aliphatic chains that belong to capsaicin structure at specific absorption bands. Microstructure of chili powders presented particles with surface imperfections as cracks and dents, and smooth surface that influence physical- chemical and flowability properties. Moisture content between 6.59 and 14.48 g H2O/100g d.s. influences the physical- chemical properties, flowability and microstructure of traditional Mexican chili powders. To improve physical- chemical properties and flowability behavior of chili powders is required that moisture content be lower than 6.59 H2O/100g d.s

Refractory Ceramics Synthesis by Solid-State Reaction Between CaCO3 (Mollusk Shell) And Al2O3 Powders.

Calcium aluminate-based refractory ceramic was developed as an innovative refractory material, using garden snail (Helix aspersa) shells as a natural source of CaCO3. A 1:1 molar ratio mixture of CaC O3 from snail shells and commercial Al2O3 powder was prepared by means of high-energy mechanical milling. The mixed powder was compacted in cylindrical samples (disks) and consolidated by sintering at 1450°C and 1500°C for 1h. The density and porosity were evaluated using the Archimedes principle, while the mechanical properties (hardness, fracture toughness, and shear modulus) were determined by indentation and ultrasonic methods, respectively. The thermal shock resistance was tested by heating samples to temperatures between 900 and 1400°C and subsequent quenching in water at room temperature. X-ray diffraction patterns of sintered samples indicate the formation of different calcium aluminate phases, such as CaAl12O (krotite/monoclinic),CaAl4O7 (grossite/monoclinic) and CaAl2O (hibonite-5H/hexagonal). The fracture toughness and shear modulus values of materials sintered at 1450°C were higher (0.48 MPa•m1/2)) and 59 GPa, respectively than those of materials sintered at 1500°C (0.43 MPa•m1/ 2 and 55 GPa, respectively). Also changes in the bulk density, hardness and thermal shock resistance values were observed in materials sintered at 1450°C and 1500°C

Physical, mechanical properties and antimicrobial analysis of a novel CaO·Al2O3 compound reinforced with Al or Ag particles

Ceramic-metal (CaO· Al2O3-Al and CaO·Al2O3-Ag) compounds were prepared by mechanical milling and consolidated through an in-situ sintering process. The aim of this work is to study the effects of the Al and Ag particles to ceramic-base compound, primarily in the microstructure, and its mechanical and antimicrobial properties. Chemical systems with a 1:1 molar ratio between CaCO3 and Al2O3 powder were formed, with the addition of 10 wt.% Al or 10 wt.% Ag, respectively. The compound material that consolidated were microstructurally characterized through X-ray diffraction, scanning electron microscopy, optic microscopy, and X-ray computed tomography. In addition, the hardness, the fracture toughness, the transversal elastic modulus, and the antimicrobial property were evaluated. The results of X-ray diffraction identified the formation of the calcium aluminate phases, such as CaO·6Al2O3 (hibonite:CA6), CaO·2Al2O3 (grossite:CA2), and CaO·Al2O3 (krotite:CA); as well as Al and Ag were identified in its respective system. In addition, the mechanical properties show changes compared to the reference material that was synthesized under the same conditions and, finally, these materials also have an antimicrobial effect, against the Staphylococcus bacterium that is common in the oral cavity, when studied in synthetic saliva.Fil: Gómez de Saravia, Sandra Gabriela. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; ArgentinaFil: Rastelli, Silvia Elena. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Tecnología de Pinturas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones en Tecnología de Pinturas; ArgentinaFil: Ortega Avilés, Mayahuel. Instituto Politécnico Nacional; MéxicoFil: González Morán, Carlos O. Universidad Autónoma del Estado de México; MéxicoFil: Rocha Rangel, Enrique. Universidad Politécnica de Victoria. Departamento de Manufactura de Materiales Avanzados; MéxicoFil: Miranda Hernández, José G.. Universidad Autónoma del Estado de México; Méxic

Effect of Glymo on the Morphological and Optical Properties of Eu3+-Doped Lu2SiO5 Films

Eu3+-(5% mol)-doped Lu2SiO5 optical quality films were prepared using the sol–gel method and dip-coating technique from lutetium and europium salts as the lanthanide precursors and tetraethyl orthosilicate (TEOS) as the silicon source. To increase the thickness of the films, 3-Glycidyloxypropyl trimethoxysilane (Glymo) was added as the rheological agent during sol formation. Structural, morphological, and luminescent properties were investigated for Lu2SiO5, Eu3+:Lu2SiO5, and Eu3+:Lu2SiO5/Glymo in order to obtain high quality in luminescent films. X-ray diffraction (XRD) results show that the incorporation of the Eu3+ ions do not affect the A-Type and B-Type monoclinic crystalline phase typical of Lu2SiO5, even after five dipping cycles on quartz substrates and a final annealing process at 1100 °C. The morphology and topography of the films were studied by SEM and AFM. These techniques revealed films without surfactant that were uniform with low rugosity while the film with surfactant presented porous hills and valleys with uneven high values of roughness. The photoluminescence spectrum of Eu3+:Lu2SiO5 films showed 2 broad emission peaks centered at 589 nm and 612 nm. The presence of Glymo in the system promoted the formation of residual Lu2Si2O7 compounds with the highest lifetime values compared with films without surfactant. The results of the films are promising for luminescent applications