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Se prohibe la reproduccion total o parcial de este libro asi como su tratamiento o distribucion informatica de alguna forma o por cualquier medio, ya sea electronico, magnetico, mecanico, fotocopia, registro u otros metodos, sin el... more
Se prohibe la reproduccion total o parcial de este libro asi como su tratamiento o distribucion informatica de alguna forma o por cualquier medio, ya sea electronico, magnetico, mecanico, fotocopia, registro u otros metodos, sin el permiso previo y por escrito del Departamento de Quimica de la Facultad de Ciencias de la Universidad de Los Andes, Merida, Venezuela.
Pterygium is a corneal alteration that can cause visual impairment, which has been traditionally treated with the sap of Sedum dendroideum D.C. The pharmacological effect of a dichloromethane extract of S. dendroideum was demonstrated and... more
Pterygium is a corneal alteration that can cause visual impairment, which has been traditionally treated with the sap of Sedum dendroideum D.C. The pharmacological effect of a dichloromethane extract of S. dendroideum was demonstrated and implemented in a pterygium model on the healing process of corneal damage caused by phorbol esters. In mice of the ICR strain, a corneal lesion was caused by intravitreal injection of tetradecanoylphorbol acetate (TPA). The evolution of the corneal scarring process was monitored with vehicle, dexamethasone, and dichloromethane extract of S. dendroideum treatments by daily ophthalmic administration for fifteen days. The lesions were evaluated in situ with highlighted images of fluorescence of the lesions. Following treatment levels in eyeballs of IL-1α, TNF-α, and IL-10 cytokines were measured. The effective dose of TPA to produce a pterygium-like lesion was determined. The follow-up of the evolution of the scarring process allowed us to define that...
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The antioxidant and metal chelating activities inJ. curcasprotein hydrolysates have been determined. The hydrolysates were produced by treatment of a nontoxic genotype with the digestive enzymes pepsin and pancreatin and then were... more
The antioxidant and metal chelating activities inJ. curcasprotein hydrolysates have been determined. The hydrolysates were produced by treatment of a nontoxic genotype with the digestive enzymes pepsin and pancreatin and then were characterized by fast protein liquid chromatography and reverse phase chromatography. Peptidic fractions with higher radical scavenging activity were analysed by matrix-assisted laser desorption/ionization mass spectrometry. The antioxidant activity was determined by measuring inhibition of the oxidative degradation ofβ-carotene and by measuring the reactive oxygen species (ROS) in Caco-2 cell cultures. Cu2+and Fe2+chelating activities were also determined. The hydrolysates inhibited the degradation ofβ-carotene and the formation of ROS in Caco-2 cells. The lower molecular weight peptidic fractions from FPLC had stronger antioxidant activity in cell cultures compared with the hydrolysates, which correlated with a higher content in antioxidant and chelating...
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Copyright © 2012 Rosa Elena Espinosa-Mendoza et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the... more
Copyright © 2012 Rosa Elena Espinosa-Mendoza et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The morphostructure of grain rice Morelos A-98 was characterized in five stages of physiological maturation, in order to generate morphometric information during the filling process. Micrographic images from optical and scanning electron microscopy coupled to a digital capture systemwere used. Images were digitally processed tomeasure different descriptors such as shape, fractal dimension, and surface texture. Results showed that, two weeks after anthesis, an accelerated grain filling was observed, particularly on those grains positioned in the distal panicle zone, compared to those located in the base of this one. As deposition of assimilates in the grain increased, the area and perimeter of the transversal cut of the g...
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The objective of this study was to produce and characterize gelatin foamed films using extrusion. Three “optimum” formulations containing tannic acid, nanoclays (Cloisite Na+), glycerol, water, and gelatin, as well as three “controls”... more
The objective of this study was to produce and characterize gelatin foamed films using extrusion. Three “optimum” formulations containing tannic acid, nanoclays (Cloisite Na+), glycerol, water, and gelatin, as well as three “controls” without tannic acid and nanoclays were prepared by calendering. Furthermore, the three “optimum” formulations were produced by extrusion film blowing only, since no stable processing conditions could be obtained for the controls. A complete set of sample characterization was performed, including morphological, mechanical, physical, and thermal properties. The results showed that besides the processing method, the thickness was also controlled by the glycerol and water content, leading to density slightly above unity, with higher values for the optimum materials. The calendered films from the optimum formulations showed overall a higher number of cells and cell density than the controls. Higher elastic moduli and tensile strengths were obtained for the ...
Composite flours containing 5%, 10%, 15%, and 20% of chia seed flour and corn were used for tortilla formulations. The effects of chia powders supplementation on the physicochemical and sensorial characteristics as well as starch... more
Composite flours containing 5%, 10%, 15%, and 20% of chia seed flour and corn were used for tortilla formulations. The effects of chia powders supplementation on the physicochemical and sensorial characteristics as well as starch digestibility of the tortillas were evaluated. Nutritionally, all chia tortillas had significantly higher levels (P < 0.001) of protein, lipids, and total dietary fibre than the control. The reduced enzymatic starch hydrolysis rate and predicted glycemic index recorded for the chia seed-added tortilla indicated slow digestion features. Sensory evaluation did not show significant (P > 0.05) differences in the attributes among tortillas. Owing to the increase in the total dietary fibre, lower digestion, and predicted glycemic index values, chia seed-added tortilla can be considered as a nutraceutical food. Therefore, the newly developed tortilla supplemented with chia seed flour could represent a valuable staple in improving the nutritional value of the...
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Research Interests: Organic Chemistry, Viscoelasticity, Structure, Rheology, Scanning Electron Microscopy, and 11 moreMorphology, Zea mays, Calcium Hydroxide, Food Sciences, Elastic Modulus, Carbohydrate, Physicochemical Properties, Carbohydrate Polymers, Frequency Domain, Viscoelastic Properties, and Transition Temperature
The aim of this work was to study the degree of hydrolysis and changes in the apparent viscosity of casein suspensions as a result of various enzymes addition. Suspensions with 3, 12 and 15 g/100 mL of casein, at pH 5.2, 6.0 and 6.5 were... more
The aim of this work was to study the degree of hydrolysis and changes in the apparent viscosity of casein suspensions as a result of various enzymes addition. Suspensions with 3, 12 and 15 g/100 mL of casein, at pH 5.2, 6.0 and 6.5 were prepared in buffer solutions. Previous ...
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Researches about the overall effect of the addition of plasticizers, cross-linking and strengthening agents in gelatin film-forming mixtures are very scarce. Also, there are not studies focused on the interactions among their individual... more
Researches about the overall effect of the addition of plasticizers, cross-linking and strengthening agents in gelatin film-forming mixtures are very scarce. Also, there are not studies focused on the interactions among their individual components, and neither those showing which sort of effects they might cause altogether. The obtainment of a gelatin film from a composite consisting of tannic acid, bentonite, and glycerol were evaluated. Nine gelatin films were manufactured by the casting method, using these materials, following a 2(3) factorial design with five replicates on the central point. The interactions among gelatin, tannic acid, and bentonite, caused a decrease in hydrogen bonds, while the polar groups of the gelatin chains were less exposed to interactions with water molecules. There was an increase in temperature and enthalpy of gelatin denaturation, due to increasing tannic acid and bentonite concentration. Tactoids were found in the gelatin films, caused mainly by bentonite poly-dispersion. A synergistic effect among tannic acid, bentonite, and glycerol, which overall improved the measured gelatin film properties was found. The best film formulation was that with 40, 150 and 250 g kg(-1) gelatin of tannic acid, bentonite and glycerol respectively, displaying a tensile strength of 38 MPa, an elongation at break of 136%, a water vapor permeability of 1.28x10(-12) g (Pa s m)(-1) and solubility of 23.4%.
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... Macho). DOI：, 作者 ：, Luis Arturo Bello-Perez；Silvia Maribel Contreras-Ramos；Rhebeca Romero-Manilla；Javier Solorza-F. 期刊 ：, Agrociencia SCI. 年，卷(期) ：, 2002, 36(2). 分类号 ：, 关键词 ：, Musa paradisiaca acetylation modified starch functional... more
... Macho). DOI：, 作者 ：, Luis Arturo Bello-Perez；Silvia Maribel Contreras-Ramos；Rhebeca Romero-Manilla；Javier Solorza-F. 期刊 ：, Agrociencia SCI. 年，卷(期) ：, 2002, 36(2). 分类号 ：, 关键词 ：, Musa paradisiaca acetylation modified starch functional properties. 正文语种 ：, eng. ...
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The objective of this work was to study, using a calorimetric method, the effect of the starch concentration on the phase properties of cassava starch dispersions, prepared using a glycerol solution and pure glycerol. Starch dispersions... more
The objective of this work was to study, using a calorimetric method, the effect of the starch concentration on the phase properties of cassava starch dispersions, prepared using a glycerol solution and pure glycerol. Starch dispersions (SD) were prepared with 10-70 g of starch.100 g –1 of SD using either a 20% glycerol solution (GS) or pure glycerol (PG). These dispersions were analyzed with a differential scanning calorimeter. The water activity of these samples was also determined at 25 °C. At low temperatures the glass transition (Tg) was well defined in samples prepared with 10-50% of starch, but was not so for SDs with 70% starch, for both glycerol solutions. For SD prepared with GS, an increase in starch concentration from 10 to 70% caused a reduction in Tg, but for SD with 10-50% starch and prepared with PG, the Tg remained constant, increasing slightly for samples with 70% starch. This behaviour agreed with that of the water activity, which increased when the starch concent...
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The objective of this work was to investigate the effect of zein and film formulation on mechanical and structural properties of native (FNS), and oxidized with 2.5% (FOSA) and 3.5% (FOSB) banana starch. The oxidized starch showed... more
The objective of this work was to investigate the effect of zein and film formulation on mechanical and structural properties of native (FNS), and oxidized with 2.5% (FOSA) and 3.5% (FOSB) banana starch. The oxidized starch showed differences from native starch due to the oxidation process, showing a decrease in lipids, proteins, and amylose. The increase of the sodium hypochlorite increased the content of carbonyl and carboxyl groups in the ranges 0.015–0.028% and 0.022–0.031%, respectively. The film obtained from FOSB displayed the highest tensile strength (5.05 MPa) and satisfactory elongation value (27.1%). The zein addition caused a decrease in these mechanical properties, as well as a significant decrease in water vapour permeability (WVP). However, films from FOSA and FOSB showed higher permeability than that of the native starch. The addition of glycerol and the level of oxidation increased the films moisture. Micrographs showed that, during the oxidation process, impurities...
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Masa or dough from nixtamalized maize with cassava (Cf) and malanga flour (Mf) addition at 20, 30 and 40 % (w/w) were prepared making seven treatments. The produced masas or doughs were subjected to chemical analysis, rheological and... more
Masa or dough from nixtamalized maize with cassava (Cf) and malanga flour (Mf) addition at 20, 30 and 40 % (w/w) were prepared making seven treatments. The produced masas or doughs were subjected to chemical analysis, rheological and mechanical tests. Tortillas were manufactured from these doughs and mechanical tests were undertaken. Doughs from tubers had less protein and lipid content but higher nitrogen free extract than the control. All doughs presented weak viscoelastic gel-like behavior, with those of Mf behaving mainly as viscous systems. Doughs with Cf showed lower decrease in both the elastic (G&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;) and viscous (G&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;) moduli than those with Mf. The adhesiveness and cohesiveness of doughs with Mf showed a higher reduction of maximum force than those with Cf. Tortillas with Cf were more elastic with higher tensile strength than those with Mf. Using Cf as partial substitution of maize might lower production costs, but Mf is not particularly suitable as maize substitute in tortilla production. Tortillas with 40 % (w/w) cassava flour, presented the highest preference on a sensory test.
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ABSTRACT The aim of this work was to study the effect of a sequential extraction of proteins from nixtamalized corn (Zea mays L) on the thermal and rheological properties of the resulting dough (masa) from the residual components.... more
ABSTRACT The aim of this work was to study the effect of a sequential extraction of proteins from nixtamalized corn (Zea mays L) on the thermal and rheological properties of the resulting dough (masa) from the residual components. Proteins were sequentially extracted from nixtamalized and control corn samples. Masas resulting after each protein fraction extraction were subjected to thermal analysis and rheological tests. The thermogram data suggested that, even though albumins and globulins were in small amount in corn samples cooked with lime, interactions albumins-lime and globulins-lime could probably be taking place and these interactions stabilized the starch crystals. However, zeins and glutelin-like proteins probably interacted with gelatinized starch, weakening its crystal integrity. Rheological characterization showed that all masas, behaved as “weak-gel- like materials”, with a predominating elastic behavior (G&#39; &gt; G&quot;), over the involved frequency range. The elastic rheological response might be attributed to the formation of a lime-polymerized protein-starch network and G&#39; and G&quot; were affected by the applied treatments.
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The morphostructure of grain rice Morelos A-98 was characterized in five stages of physiological maturation, in order to generate morphometric information during the filling process. Micrographic images from optical and scanning electron... more
The morphostructure of grain rice Morelos A-98 was characterized in five stages of physiological maturation, in order to generate morphometric information during the filling process. Micrographic images from optical and scanning electron microscopy coupled to a digital capture system were used. Images were digitally processed to measure different descriptors such as shape, fractal dimension, and surface texture. Results showed that, two weeks after anthesis, an accelerated grain filling was observed, particularly on those grains positioned in the distal panicle zone, compared to those located in the base of this one. As deposition of assimilates in the grain increased, the area and perimeter of the transversal cut of the grains also increased (P≤0.05); meanwhile, the rounded shape factor tended to increase as well (P≤0.05), while the elliptic shape factor decreased. As the dehydrated endosperm passed from “milky” to “doughy” stages, values of fractal dimension area and endosperm per...
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Abstract Okenia hypogaea (Schlech. & Cham.) belongs to the family of the Nyctaginacea, which produces a seed that is composed mainly of starch, the probable origin of Okenia hypogaea is Mexico. The aim of this work was to isolate the... more
Abstract Okenia hypogaea (Schlech. & Cham.) belongs to the family of the Nyctaginacea, which produces a seed that is composed mainly of starch, the probable origin of Okenia hypogaea is Mexico. The aim of this work was to isolate the starch from Okenia hypogaea ...
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The aim of this work was to study the rheological behavior of Okenia hypogea starch dispersions (OSD) in aqueous solution (90/10, v/v) of dimethyl sulfoxide (DMSO). Okenia starch dispersions with 3 and 7 % (w/v) total solids were prepared... more
The aim of this work was to study the rheological behavior of Okenia hypogea starch dispersions (OSD) in aqueous solution (90/10, v/v) of dimethyl sulfoxide (DMSO). Okenia starch dispersions with 3 and 7 % (w/v) total solids were prepared at 20 °C and rheological tests were ...
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The aim of this work was to study the degree of hydrolysis and changes in the apparent viscosity of casein suspensions as a result of various enzymes addition. Suspensions with 3, 12 and 15 g/100 mL of casein, at pH 5.2, 6.0 and 6.5 were... more
The aim of this work was to study the degree of hydrolysis and changes in the apparent viscosity of casein suspensions as a result of various enzymes addition. Suspensions with 3, 12 and 15 g/100 mL of casein, at pH 5.2, 6.0 and 6.5 were prepared in buffer solutions. Previous ...
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Antioxidant and chelating activities were determined in protein hydrolysates that were produced by treating a protein isolate of a non-toxic genotype of Jatropha curcas with the protease preparation alcalase. 50 min protein hydrolysate... more
Antioxidant and chelating activities were determined in protein hydrolysates that were produced by treating a protein isolate of a non-toxic genotype of Jatropha curcas with the protease preparation alcalase. 50 min protein hydrolysate with a degree of hydrolysis of 31.7% showed highest antioxidant and chelating activity. These activities were also determined in six peptidic fractions that were separated by gel filtration chromatography of the 50 min hydrolysate. The lower-molecular-weight peptidic fractions had the highest antioxidant and chelating activities, which correlated with a higher content in antioxidant and chelating amino acids such as tyrosine and histidine. Results show that J. curcas represents a good source of bioactive peptides. This may be important for the revalorization of defatted J. curcas flour, a by-product resulting form oil extraction for biodiesel production. This is especially important in Third World and developing countries such as Mexico.
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... Luis A Bello-Pérez 1,* ,; Perla Osorio-Díaz 1 ,; Edith Agama-Acevedo 1 ,; Javier Solorza-Feria 1 ,; Jorge F Toro-Vázquez 2 ,; Octavio Paredes-López 3. ... 7 Almeida-Dominguez HD, Cepeda M and Rooney L, Properties of commercial... more
... Luis A Bello-Pérez 1,* ,; Perla Osorio-Díaz 1 ,; Edith Agama-Acevedo 1 ,; Javier Solorza-Feria 1 ,; Jorge F Toro-Vázquez 2 ,; Octavio Paredes-López 3. ... 7 Almeida-Dominguez HD, Cepeda M and Rooney L, Properties of commercial nixtamalized corn flour. ...
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ABSTRACT The effect of a small amount of carbon nanotubes (CNT) on the water content and physical properties of gelatin films with glycerol were evaluated. Control films and those with 0.001% (w/w) CNT addition were prepared. Water... more
ABSTRACT The effect of a small amount of carbon nanotubes (CNT) on the water content and physical properties of gelatin films with glycerol were evaluated. Control films and those with 0.001% (w/w) CNT addition were prepared. Water isotherms adsorption and water vapor permeability, were undertaken on the gelatin films to asses barrier characteristics. Tensile strength and elongation at break were evaluated with a texture meter, while hardness and elastic modulus were measured with a nanoindentation tester, all these tests were measured at 22%, 40%, 58% and 75% RH. Atomic force, environmental and field emission scanning electron microscopy, were used to see the films morpho-structure. The data adsorption isotherms fitted well all models tried. An increase in RH decreased the tensile strength, and increased the elongation at break of all films. The CNT addition did not affect significantly the films barrier properties (p &gt; 0.05), but it caused an increase of about 11.36% on the elongation at break of films, at any RH higher than 40%; with no effect on the tensile strength and hardness. Films image analysis, showed a morpho-structure with high ordering, which might well correlate with CNT addition to the protein matrix. CNT were found embedded in the polymeric matrix. (c) 2013 Elsevier Ltd. All rights reserved.
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Although nixtamalization is widely used in the food industry, a comprehensive understanding of the influence of proteins on the viscoelastic behavior and thermal properties in masa is still lacking. In this work, the effect of protein... more
Although nixtamalization is widely used in the food industry, a comprehensive understanding of the influence of proteins on the viscoelastic behavior and thermal properties in masa is still lacking. In this work, the effect of protein changes and its ...
Research Interests: Engineering, Heat Treatment, Polymerization, Biological Sciences, Models, and 12 moreDifferential scanning calorimetry, Maize, Emulsion polymerisation, Cereal, Food Industry, Protein Interaction, Model System, Moisture Content, Thermal Properties, Application of Biopolymers, Cereal Science, and Viscoelastic Properties
Page 1. Original article Optimisation of conditions for glucose syrup production from banana (Musa paradisiaca L.) pulp using response surface methodology J. Rodolfo Rendón-Villalobos,* Javier Solorza-Feria &amp;amp; Alondra... more
Page 1. Original article Optimisation of conditions for glucose syrup production from banana (Musa paradisiaca L.) pulp using response surface methodology J. Rodolfo Rendón-Villalobos,* Javier Solorza-Feria &amp;amp; Alondra Aguilar-Sandoval ...
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ABSTRACT The rheological behaviour and gel strength of hydrocolloid mixture systems (HMSs) of carboxymethylated flamboyant gum (CFG) with protein hydrolysates (PHs) of Phaseolus lunatus were examined to evaluate the influence of the... more
ABSTRACT The rheological behaviour and gel strength of hydrocolloid mixture systems (HMSs) of carboxymethylated flamboyant gum (CFG) with protein hydrolysates (PHs) of Phaseolus lunatus were examined to evaluate the influence of the protein/polysaccharide ratio (2:1 and 3:1), pH (3 and 9) and concentration of solids, according to a 23 factorial design. The protein concentrate of P. lunatus was hydrolysed with pepsin–pancreatin enzymes. The flow curve results were fitted to the Ostwald–de Waele model. The flow behaviour index (0.66–0.78) for all conditions studied was indicative of the shear-thinning behaviour. For the HMS, the consistency index (k) values ranged from 0.4 Pa sn to 1.2 Pa sn. The analyses of variance showed that the ratio of PH/CFG and pH were the main variables that had significant effect on k values (P &lt; 0.05). Only PH system presented a weak gel-like viscoelastic behaviour. Both functional properties were affected by the protein degree of hydrolysis (DH).