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Oriente 1ra. Seccion, Mexico

Walker R.P.,University of Perugia | Famiani F.,University of Perugia | Baldicchi A.,University of Perugia | Cruz-Castillo J.G.,University of the East of Mexico | Inglese P.,University of Palermo
Scientia Horticulturae

The aim of this study was to investigate changes in the abundance of a number of enzymes in the peel, core and seeds of fruits of Opuntia ficus-indica (L.) Miller during development. The enzymes studied were phosphoenolpyruvate carboxylase (PEPC; EC:, ribulose-1,5-bisphosphate carboxylase/oxygenase (RUBISCO; EC:, aldolase (EC:, pyruvate, orthophosphate dikinase (PPDK; EC:, phosphoenolpyruvate carboxykinase (PEPCK; EC: and aspartate aminotransferase (AspAT; EC: To detect these enzymes, antibodies specific for each enzyme were used to probe Western blots of sodium dodecyl sulphate polyacrylamide gels. Fruit weight increased throughout development, and during ripening there was both an accumulation of total soluble solids and a decrease in both total titratable acidity and chlorophyll content. In the early stages of its growth the polypeptide pattern and enzyme composition of the fruit chlorenchyma was similar to that of the cladode. In the peel of the fruit PEPC, RUBISCO, plastidic aldolase and PPDK decreased to undetectable amounts as ripening progressed. PEPCK was not detected in either the chlorenchyma of the fruit or cladode. This showed that O. ficus-indica is not a PEPCK type CAM plant and that in this fruit PEPCK is not involved in the metabolism of organic acids. Cytosolic aldolase and AspAT were present in both the peel and core throughout development. The seeds accumulated storage proteins before the fruit ripened, and the abundance of all the enzymes studied declined once the accumulation of storage proteins was complete. © 2011 Elsevier B.V. Source

Velasco-Perez A.,University of the East of Mexico | Alvarez-Ramirez J.,Metropolitan Autonomous University | Solar-Gonzalez R.,Istmo University of Mexico
Revista Mexicana de Ingeniera Qumica

This paper addresses the multiple input - single output (MISO) control problem of a simple generic model of a CSTR. The control design is based on simple models and the inversion of dead-beat filters. It is proposed a synthesis procedure of controllers based on the factorization of MISO plants that leads to a parallel control structure. The proposed controller performs a balance in the use of the control inputs via an optimization problem. Numerical simulations show the performance and comparison of the control scheme against its counterparts SISO. Source

Feria-Ortiz M.,University of the East of Mexico | Manrquez-Morn N.L.,University of Central Mexico | De Oca A.N.-M.,National University of Costa Rica
Herpetological Monographs

The Mexican Plestiodon brevirostris species group (Squamata: Scincidae) is composed of seven nominal species. The wide-ranging P. brevirostris is a polytypic species composed of five subspecies: P. b. brevirostris, P. b. bilineatus, P. b. dicei, P. b. indubitus, and P. b. pineus. A tree-based approach for species delimitation with mtDNA data was used to test the traditional species-level taxonomy of P. brevirostris preliminarily. A haplotype phylogeny for all of the species and subspecies in the P. brevirostris group, except P. colimensis, was inferred. The mtDNA data consisted of sequences encompassing the genes encoding 16S rRNA (part), ND1, and associated tRNAs (1355 base pairs), which were analyzed with Bayesian methods. Then, a search for diagnostic morphological characters for the putative species delimited by this approach was performed. The results indicate that the P. brevirostris group is paraphyletic with respect to P. lynxe, and that P. brevirostris actually is composed of at least five distinct lineages disguised by traditional taxonomy: P. b. brevirostris, P. b. bilineatus, P. b. dicei, and the eastern populations of P. b indubitus (from Morelos, Guerrero, and México) represent distinct species, whereas the western populations of P. b. indubitus (from Colima and Jalisco) represent an undescribed species. The data cannot resolve whether P. b. pineus is conspecific with P. b. dicei or P. b. dicei is a paraphyletic (?=?nonexclusive) species relative to an exclusive P. b. pineus. Thus, the status of P. b. pineus remains uncertain. The haplotype phylogeny also suggests that P. b. brevirostris may represent more than one species. © 2011 The Herpetologists' League, Inc. Source

Pascual-Pineda L.A.,University of Xalapas | Flores-Andrade E.,University of the East of Mexico | Alamilla-Beltran L.,National Polytechnic Institute of Mexico | Chanona-Perez J.J.,National Polytechnic Institute of Mexico | And 3 more authors.
Food and Bioprocess Technology

Carotenoids were encapsulated by means of coacervation by using a nanostructured material (NE) prepared with alginate/zeolite valfor 100 (1:3) and another that was non-nanostructured (AA) prepared with alginate at 2 %. The diameter of the AA and NE capsules was ≈1,200 μm. The NE protected the carotenoids at higher water activities (a w) than the AA. The highest retention of carotenoids (7,200 mg/kg dry solids for NE and 2,230 mg/kg dry solids for AA) was observed at water activities corresponding to the minimal integral entropy (≈0.35-0.45 for NE and ≈0.1 for AA). According to the enthalpy-entropy compensation, the water adsorption in the AA capsules was enthalpy driven at a w range of 0.115-0.973. However, the NE showed two zones: (1) at low a w (0.115-0.4), the water adsorption was controlled by entropy and (2) over an a w range of 0.4-0.973, controlled by enthalpy. Atomic force microscope images, moisture content corresponding to micropore volume and thermodynamic properties suggest that the adsorption process and the carotenoids stability were controlled by entropic barriers when the water molecules were adsorbed in the micropores (nanopores with pore diameter <2 nm). The practical use of these results is that increasing the number of micropores in the solid matrix of wall materials is possible to improve the preservation of nutrients and functional substances during processing and storage of foods. © 2013 Springer Science+Business Media New York. Source

Jimenez M.,University of Veracruz | Flores-Andrade E.,University of the East of Mexico | Pascual-Pineda L.A.,University of Veracruz | Beristain C.I.,University of Veracruz
LWT - Food Science and Technology

Lactobacillus paracasei subsp. paracasei LBC81 microorganisms were encapsulated by fluidized bed drying using water-alginate system incorporating potato starch. The capsules were stored for seven weeks in aw (s) from 0.103 to 0.846 at 25, 35 and 45°C. The quantitative analysis of microorganisms indicated that the survival of the strain decreased more rapidly over water activity of 0.536, which was considered as critical for maintaining these alive. This water activity can be obtained using the Rockland analysis. The enthalpy-entropy compensation revealed that encapsulated probiotics were kept alive when the adsorption process was controlled by entropy, which was where the critical water activity occurred. •Viability of encapsulated probiotics decreases above water activity of 0.536.•Thermodynamic compensation provides the critical water activity for the bacterial survival.•The best bacterial stability was entropy driven. © 2014 Elsevier Ltd. Source

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