Xiang B.Y.,McGill University |
Ngadi M.O.,McGill University |
Ochoa-Martinez L.A.,Technological Institute of Durango |
Simpson M.V.,McGill University
Food and Bioprocess Technology | Year: 2011
Effects of pulsed electric fields (PEF) on structural modification and surface hydrophobicity were assessed for whey protein isolate (WPI) of protein concentrations (3% and 5%) using fluorescence spectroscopy. The effects of a factorial combination of electric field intensities (12, 16, and 20 kV cm -1) and number of pulses (10, 20, and 30) on the intrinsic tryptophan fluorescence intensity, extrinsic fluorescence intensity, and surface hydrophobicity of WPI were evaluated. PEF treatments of WPI resulted in increases in the intrinsic tryptophan fluorescence intensity and led to 2-4-nm red shifts in emission wavelengths, indicating changes in the polarity of tryptophan residues microenvironment in whey proteins from a less polar to a more polar environment. The extrinsic fluorescence intensity of WPI increased with PEF treatments, but with 2-4-nm blue shifts, indicating partial denaturation of WPI fractions and exposure of more hydrophobic regions under these PEF treatments. Thus, under the conditions studied, PEF treatments of WPI yielded increases in surface hydrophobicity. The study confirmed that PEF treatments resulted in whey protein structure modifications. These results suggested that controlled PEF could be applied to process liquids food including WPI ingredients and modify their structure and function in order to get desired food products. © 2009 Springer Science + Business Media, LLC.
Valencia-Vazquez R.,Technological Institute of Durango |
Perez-Lopez M.E.,National Polytechnic Institute of Mexico |
Vicencio-De-La-Rosa M.G.,Municipality of Durango |
Martinez-Prado M.A.,Technological Institute of Durango |
Rubio-Hernandez R.,National Polytechnic Institute of Mexico
Waste Management and Research | Year: 2014
As society evolves its welfare level increases, and as a consequence the amount of municipal solid waste increases, imposing great challenges to municipal authorities. In developed countries, municipalities have established integrated management schemes to handle, treat, and dispose of municipal solid waste in an economical and environmentally sound manner. Municipalities of developing and transition countries are not exempted from the challenges involving municipal solid waste handling, but their task is not easy to accomplish since they face budget deficits, lack of knowledge, and deficiencies in infrastructure and equipment. In the northern territory of Mexico, the municipality of Durango is facing the challenge of increased volumes of waste with a lack of adequate facilities and infrastructure. This article analyses the evolution of the municipal solid waste management of Durango city, which includes actions such as proper facilities construction, equipment acquisition, and the implementation of social programmes. The World Bank, offering courses to municipal managers on landfill operation and waste management, promoted the process of knowledge and technology transfer. Thereafter, municipal authorities attended regional and some international workshops on waste management. In addition they followed suggestions of international contractors and equipment dealers with the intention to improve the situation of the waste management of the city. After a 15-year period, transfer of knowledge and technology resulted in a modern municipal solid waste management system in Durango municipality. The actual system did not reach the standard levels of an integrated waste management system, nevertheless, a functional evaluation shows clear indications that municipality actions have put them on the right pathway. © The Author(s) 2014.
Jimenez-Islas D.,Polytechnic University of Pachuca |
Paez-Lerma J.,Technological Institute of Durango |
Soto-Cruz N.O.,Technological Institute of Durango |
Gracida J.,Polytechnic University of Pachuca |
Gracida J.,Autonomous University of Queretaro
Food Technology and Biotechnology | Year: 2014
In this work the effects of pH and temperature on ethanol production from red beet juice by the strains Saccharomyces cerevisiae ITD00196 and S. cerevisiae ATCC 9763 are studied. Logistic, Pirt, and Luedeking-Piret equations were used to describe quantitatively the microbial growth, substrate consumption, and ethanol production, respectively. The two S. cerevisiae strains used in this study were able to produce ethanol with high yield and volumetric productivity under acid and thermal stress conditions. The equations used to model the fermentation kinetics fit very well with the experimental data, thus establishing that ethanol production was growth-associated under the evaluated conditions. The yeast S. cerevisiae ITD00196 had the best fermentative capacity and could be considered as an interesting option to develop bioprocesses for ethanol production.
Nunez-Ramirez D.M.,Technological Institute of Durango |
Medina-Torres L.,National Autonomous University of Mexico |
Valencia-Lopez J.J.,Metropolitan Autonomous University |
Calderas F.,National Autonomous University of Mexico |
And 3 more authors.
Journal of Microbiology and Biotechnology | Year: 2012
Fermentation with filamentous fungi in a bioreactor is a complex dynamic process that is affected by flow conditions and the evolution of the rheological properties of the medium. These properties are mainly affected by the biomass concentration and the morphology of the fungus. In this work, the rheological properties of a fermentation with the fungus Beauveria bassiana under different hydrodynamic conditions were studied and the rheological behavior of this broth was simulated through a mixture of carboxymethyl cellulose sodium and cellulose fibers (CMCNa-SF). The bioreactor was a 10 L CSTR tank operated at different stir velocities. Rheological results were similar at 100 and 300 rpm for both systems. However, there was a significant increase in the viscosity accompanied by a change in the consistence index, calculated according to the power law model, for both systems at 800 rpm. The systems exhibited shear-thinning behavior at all stir velocities, which was determined with the power law model. The mixing time was observed to increase as the cellulose content in the system increased and, consequently, the efficiency of mixing diminished. These results are thought to be due to the rheological and morphological similarities of the two fungal systems. These results will help in the optimization of scale-up production of these fungi. © The Korean Society for Microbiology and Biotechnology.
Delgado E.,Technological Institute of Durango |
Vences-Montano M.I.,Technological Institute of Durango |
Hernandez Rodriguez J.V.,Technological Institute of Durango |
Rocha-Guzman N.,Technological Institute of Durango |
And 5 more authors.
Emirates Journal of Food and Agriculture | Year: 2012
There is a need to develop new food products with high protein quality and a high caloric value, high acceptability and low costs for low income families. The aim of this investigation was to evaluate in vivo an extruded bean-corn product, supplemented with Ca and Zn, as a potential nutritional snack. Extruded and nonextruded bean-corn flours were fed to rats. Antinutritional factors, rat weight and length, femur weight and heart weight and volume were determined. Microscopy pictures of rat liver were taken. The antinutritional factors present in the studied bean variety did not affect rat growth or internal organ characteristics. Bean-corn diets affected (p<0.05) rat weight and produced liver alterations, probably because of interference by bean protein with intestinal or systemic metabolism. Ca and Zn supplementation is not necessary in a bean-corn extruded snack for rats.