The Experts below are selected from a list of 46020 Experts worldwide ranked by ideXlab platform
José M. Sendra - One of the best experts on this subject based on the ideXlab platform.
-
Determination of the antiradical activity and Kinetics of pomegranate juice using 2,2-diphenylpicyrl-1-hydrazyl as the antiradical probe
Food Science and Technology International, 2014Co-Authors: Manuela Cerdán-calero, José M. Sendra, Enrique SentandreuAbstract:Whole fruit pomegranate (Punica granatum L.) juice of the ‘Wonderful’ cultivar was characterized through the elucidation of its antiradical Kinetics and activity using 2,2-diphenyl-1-picrylhydrazyl as the antiradical probe. Time-dependent concentration of 2,2-diphenyl-1-picrylhydrazyl during its reduction by the juice has been adjusted through a non-linear parametric fitting. Determined total antiradical activity was high, able to reduce 84.58 µmol/l of 2,2-diphenyl-1-picrylhydrazyl per concentration unit of juice (µl/ml), equivalent to a concentration of 42.29 mmol/l of ascorbic acid (or Trolox). Partial antiradical activities due to the fast-, medium- and Slow-Kinetics were 49.09, 18.16 and 17.33 µmol/l of reduced 2,2-diphenyl-1-picrylhydrazyl per concentration unit of juice (µl/ml), respectively. The corresponding rate constant for the fast-, medium- and Slow-Kinetics were κ1 = 6.03, κ2 = 0.169 and κ3 = 0.0094 (μl l)/(ml µmol min), respectively. This methodology allows characterization of samples throu...
-
effect of technological processes and storage on flavonoids content and total cumulative fast Kinetics and cumulative Slow Kinetics antiradical activities of citrus juices
European Food Research and Technology, 2007Co-Authors: Enrique Sentandreu, José L. Navarro, José M. SendraAbstract:Juices from the mandarin Clemenules (Citrus clementina Hort. ex Tan.), the tangor Ortanique (Citrus reticulata Blanco × Citrus sinensis Osb.) and the sweet orange Valencia Late (Citrus sinensis) have been industrially squeezed, pasteurized, concentrated and stored under refrigeration (4 °C) and at room temperature (20 °C). After each process, the flavanone-7-O-glycosides (FGs) and fully methoxylated flavones (FMFs) contents as well as total, cumulative fast-Kinetics and cumulative Slow-Kinetics antiradical activities were determined and compared with those from the corresponding fresh hand-squeezed juices. Neither industrial-squeezing, nor pasteurization or concentration significantly affected FGs and FMFs contents and antiradical activities of assayed juices. Storage caused a slight decrease of the FMFs contents but a significant reduction of both soluble hesperidin contents and cumulative fast-Kinetics antiradical activities in all assayed juices. These decreases were dependent on storage temperature. Characteristic values of the varietal characterization parameters, which are derived from the FMFs contents and antiradical activities of fresh hand-squeezed juices, held valid for industrially squeezed, pasteurized and concentrated juices. After storage, however, only the FMFs-derived varietal characterization parameters and cumulative Slow-Kinetics antiradical activity remained valid for the resulting juices.
-
Kinetic Model for the Antiradical Activity of the Isolated p-Catechol Group in Flavanone Type Structures Using the Free Stable Radical 2,2-Diphenyl-1-picrylhydrazyl as the Antiradical Probe
Journal of agricultural and food chemistry, 2007Co-Authors: José M. Sendra, Enrique Sentandreu, José L. NavarroAbstract:The time evolution of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) concentration in four solvents (methanol, ethanol, propanol, and acetonitrile) during its reduction by three flavanones containing an isolated p-catechol group (taxifolin, eriodyctiol, and fustin) as well as the time evolution of the mass spectra of the reaction mixture has been determined by spectrophotometry and liquid mass spectrometry, respectively. In alcoholic solvents the reduction curves consisted of an initial short but fast Kinetics step followed by a longer Slow Kinetics step; in contrast, in acetonitrile the reduction curves completely lacked the Slow Kinetics step. From the results, a kinetic model for the reaction of reduction of the DPPH• by the isolated p-catechol group in flavanone type structures is proposed. According to this model, the p-catechol group rapidly transfers two hydrogen atoms to DPPH•, through a fast rate constant k1, yielding the corresponding o-quinone. Then, the intermediate o-quinone forms an adduct wi...
-
total cumulative fast Kinetics and cumulative Slow Kinetics antiradical activities of juices from clementine citrus clementina clementine hybrids and satsuma citrus unshiu cultivars and their utility as discriminant variables
European Food Research and Technology, 2007Co-Authors: Enrique Sentandreu, Luis Izquierdo, José M. SendraAbstract:Mandarin juices from three pure clementine (Citrus clementina Hort. ex Tan.) cultivars: Clemenules, Hernandine and Marisol, two clementine-hybrid cultivars: Nova (clementine×tangelo Orlando) and Fortune (clementine× mandarin Dancy), one mandarin-hybrid cultivar: Ortanique (mandarin×orange) and one satsuma (Citrus unshiu Marc) cultivar: Clauselline have been analysed for determination of total, cumulative fast-Kinetics and cumulative Slow-Kinetics antiradical activities. Total antiradical activity followed the order: pure clementine and Nova> Ortanique>Fortune and Clauselline. Cumulative fast-Kinetics antiradical activity was the major contributor to total antiradical activity, accounting for about 87% as average. Ascorbic acid content was the major contributor to cumulative fast-Kinetics antiradical activity, accounting for about 93.5% as average. A weak correlation (r 2=0.151) between total flavanone-7-O-glycosides (FGs, Narirutin, Hesperidin and Didymin) content and cumulative Slow-Kinetics antiradical activity was observed. However, ascorbic acid and total FGs contents showed a significant negative correlation (r 2=0.658). By using the cumulative fast-Kinetics and Slow-Kinetics antiradical activities as variables, all the assayed juices were significantly discriminated (<0.05) by statistical multivariate discriminant analysis.
-
Total, cumulative fast-Kinetics and cumulative Slow-Kinetics antiradical activities of juices from clementine (Citrus clementina), clementine-hybrids and satsuma (Citrus unshiu) cultivars and their utility as discriminant variables
European Food Research and Technology, 2006Co-Authors: Enrique Sentandreu, Luis Izquierdo, José M. SendraAbstract:Mandarin juices from three pure clementine ( Citrus clementina Hort. ex Tan.) cultivars: Clemenules, Hernandine and Marisol, two clementine-hybrid cultivars: Nova (clementine×tangelo Orlando) and Fortune (clementine× mandarin Dancy), one mandarin-hybrid cultivar: Ortanique (mandarin×orange) and one satsuma ( Citrus unshiu Marc) cultivar: Clauselline have been analysed for determination of total, cumulative fast-Kinetics and cumulative Slow-Kinetics antiradical activities. Total antiradical activity followed the order: pure clementine and Nova> Ortanique>Fortune and Clauselline. Cumulative fast-Kinetics antiradical activity was the major contributor to total antiradical activity, accounting for about 87% as average. Ascorbic acid content was the major contributor to cumulative fast-Kinetics antiradical activity, accounting for about 93.5% as average. A weak correlation ( r ^2=0.151) between total flavanone-7- O -glycosides (FGs, Narirutin, Hesperidin and Didymin) content and cumulative Slow-Kinetics antiradical activity was observed. However, ascorbic acid and total FGs contents showed a significant negative correlation ( r ^2=0.658). By using the cumulative fast-Kinetics and Slow-Kinetics antiradical activities as variables, all the assayed juices were significantly discriminated (
Enrique Sentandreu - One of the best experts on this subject based on the ideXlab platform.
-
Determination of the antiradical activity and Kinetics of pomegranate juice using 2,2-diphenylpicyrl-1-hydrazyl as the antiradical probe
Food Science and Technology International, 2014Co-Authors: Manuela Cerdán-calero, José M. Sendra, Enrique SentandreuAbstract:Whole fruit pomegranate (Punica granatum L.) juice of the ‘Wonderful’ cultivar was characterized through the elucidation of its antiradical Kinetics and activity using 2,2-diphenyl-1-picrylhydrazyl as the antiradical probe. Time-dependent concentration of 2,2-diphenyl-1-picrylhydrazyl during its reduction by the juice has been adjusted through a non-linear parametric fitting. Determined total antiradical activity was high, able to reduce 84.58 µmol/l of 2,2-diphenyl-1-picrylhydrazyl per concentration unit of juice (µl/ml), equivalent to a concentration of 42.29 mmol/l of ascorbic acid (or Trolox). Partial antiradical activities due to the fast-, medium- and Slow-Kinetics were 49.09, 18.16 and 17.33 µmol/l of reduced 2,2-diphenyl-1-picrylhydrazyl per concentration unit of juice (µl/ml), respectively. The corresponding rate constant for the fast-, medium- and Slow-Kinetics were κ1 = 6.03, κ2 = 0.169 and κ3 = 0.0094 (μl l)/(ml µmol min), respectively. This methodology allows characterization of samples throu...
-
effect of technological processes and storage on flavonoids content and total cumulative fast Kinetics and cumulative Slow Kinetics antiradical activities of citrus juices
European Food Research and Technology, 2007Co-Authors: Enrique Sentandreu, José L. Navarro, José M. SendraAbstract:Juices from the mandarin Clemenules (Citrus clementina Hort. ex Tan.), the tangor Ortanique (Citrus reticulata Blanco × Citrus sinensis Osb.) and the sweet orange Valencia Late (Citrus sinensis) have been industrially squeezed, pasteurized, concentrated and stored under refrigeration (4 °C) and at room temperature (20 °C). After each process, the flavanone-7-O-glycosides (FGs) and fully methoxylated flavones (FMFs) contents as well as total, cumulative fast-Kinetics and cumulative Slow-Kinetics antiradical activities were determined and compared with those from the corresponding fresh hand-squeezed juices. Neither industrial-squeezing, nor pasteurization or concentration significantly affected FGs and FMFs contents and antiradical activities of assayed juices. Storage caused a slight decrease of the FMFs contents but a significant reduction of both soluble hesperidin contents and cumulative fast-Kinetics antiradical activities in all assayed juices. These decreases were dependent on storage temperature. Characteristic values of the varietal characterization parameters, which are derived from the FMFs contents and antiradical activities of fresh hand-squeezed juices, held valid for industrially squeezed, pasteurized and concentrated juices. After storage, however, only the FMFs-derived varietal characterization parameters and cumulative Slow-Kinetics antiradical activity remained valid for the resulting juices.
-
Kinetic Model for the Antiradical Activity of the Isolated p-Catechol Group in Flavanone Type Structures Using the Free Stable Radical 2,2-Diphenyl-1-picrylhydrazyl as the Antiradical Probe
Journal of agricultural and food chemistry, 2007Co-Authors: José M. Sendra, Enrique Sentandreu, José L. NavarroAbstract:The time evolution of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) concentration in four solvents (methanol, ethanol, propanol, and acetonitrile) during its reduction by three flavanones containing an isolated p-catechol group (taxifolin, eriodyctiol, and fustin) as well as the time evolution of the mass spectra of the reaction mixture has been determined by spectrophotometry and liquid mass spectrometry, respectively. In alcoholic solvents the reduction curves consisted of an initial short but fast Kinetics step followed by a longer Slow Kinetics step; in contrast, in acetonitrile the reduction curves completely lacked the Slow Kinetics step. From the results, a kinetic model for the reaction of reduction of the DPPH• by the isolated p-catechol group in flavanone type structures is proposed. According to this model, the p-catechol group rapidly transfers two hydrogen atoms to DPPH•, through a fast rate constant k1, yielding the corresponding o-quinone. Then, the intermediate o-quinone forms an adduct wi...
-
total cumulative fast Kinetics and cumulative Slow Kinetics antiradical activities of juices from clementine citrus clementina clementine hybrids and satsuma citrus unshiu cultivars and their utility as discriminant variables
European Food Research and Technology, 2007Co-Authors: Enrique Sentandreu, Luis Izquierdo, José M. SendraAbstract:Mandarin juices from three pure clementine (Citrus clementina Hort. ex Tan.) cultivars: Clemenules, Hernandine and Marisol, two clementine-hybrid cultivars: Nova (clementine×tangelo Orlando) and Fortune (clementine× mandarin Dancy), one mandarin-hybrid cultivar: Ortanique (mandarin×orange) and one satsuma (Citrus unshiu Marc) cultivar: Clauselline have been analysed for determination of total, cumulative fast-Kinetics and cumulative Slow-Kinetics antiradical activities. Total antiradical activity followed the order: pure clementine and Nova> Ortanique>Fortune and Clauselline. Cumulative fast-Kinetics antiradical activity was the major contributor to total antiradical activity, accounting for about 87% as average. Ascorbic acid content was the major contributor to cumulative fast-Kinetics antiradical activity, accounting for about 93.5% as average. A weak correlation (r 2=0.151) between total flavanone-7-O-glycosides (FGs, Narirutin, Hesperidin and Didymin) content and cumulative Slow-Kinetics antiradical activity was observed. However, ascorbic acid and total FGs contents showed a significant negative correlation (r 2=0.658). By using the cumulative fast-Kinetics and Slow-Kinetics antiradical activities as variables, all the assayed juices were significantly discriminated (<0.05) by statistical multivariate discriminant analysis.
-
Total, cumulative fast-Kinetics and cumulative Slow-Kinetics antiradical activities of juices from clementine (Citrus clementina), clementine-hybrids and satsuma (Citrus unshiu) cultivars and their utility as discriminant variables
European Food Research and Technology, 2006Co-Authors: Enrique Sentandreu, Luis Izquierdo, José M. SendraAbstract:Mandarin juices from three pure clementine ( Citrus clementina Hort. ex Tan.) cultivars: Clemenules, Hernandine and Marisol, two clementine-hybrid cultivars: Nova (clementine×tangelo Orlando) and Fortune (clementine× mandarin Dancy), one mandarin-hybrid cultivar: Ortanique (mandarin×orange) and one satsuma ( Citrus unshiu Marc) cultivar: Clauselline have been analysed for determination of total, cumulative fast-Kinetics and cumulative Slow-Kinetics antiradical activities. Total antiradical activity followed the order: pure clementine and Nova> Ortanique>Fortune and Clauselline. Cumulative fast-Kinetics antiradical activity was the major contributor to total antiradical activity, accounting for about 87% as average. Ascorbic acid content was the major contributor to cumulative fast-Kinetics antiradical activity, accounting for about 93.5% as average. A weak correlation ( r ^2=0.151) between total flavanone-7- O -glycosides (FGs, Narirutin, Hesperidin and Didymin) content and cumulative Slow-Kinetics antiradical activity was observed. However, ascorbic acid and total FGs contents showed a significant negative correlation ( r ^2=0.658). By using the cumulative fast-Kinetics and Slow-Kinetics antiradical activities as variables, all the assayed juices were significantly discriminated (
Claudia Lizbeth Martínez-gonzález - One of the best experts on this subject based on the ideXlab platform.
-
Slow Kinetics of water escape from randomly folded foils
Physical Review E, 2011Co-Authors: Alexander S. Balankin, S. Matías Gutierres, D. Samayoa Ochoa, J. Patiño Ortiz, B. Espinoza Elizarraraz, Claudia Lizbeth Martínez-gonzálezAbstract:Folded configurations of thin matter are ubiquitousin nature [1], ranging from nanoparticle membranes [2]to hand-folded paper [3,4] and fault-related geologicalformations [5]. The physics of folded states display manyinteresting phenomena associated with statistical properties offolding configurations [6,7]. The porosity of randomly foldedsheet can be as large as 99% and decreases with increase ofthe contraction ratio
-
Slow Kinetics of water escape from randomly folded foils.
Physical review. E Statistical nonlinear and soft matter physics, 2011Co-Authors: Alexander S. Balankin, S. Matías Gutierres, D. Samayoa Ochoa, J. Patiño Ortiz, B. Espinoza Elizarraraz, Claudia Lizbeth Martínez-gonzálezAbstract:We study the Kinetics of water escape from balls folded from square aluminum foils of different thickness and edge size. We found that the water discharge rate obeys the scaling relation Q ∝ V{P}(M-M{r}){α} with the universal scaling exponents α=3 ± 0.1, where V{P} is the volume of pore space, M(t) is the actual mass of water in the ball, and M{r} is the mass of residual water. The last is found to be a power-law function of V{P}. The relation of these findings to the fractal geometry of randomly folded matter is discussed.
José L. Navarro - One of the best experts on this subject based on the ideXlab platform.
-
effect of technological processes and storage on flavonoids content and total cumulative fast Kinetics and cumulative Slow Kinetics antiradical activities of citrus juices
European Food Research and Technology, 2007Co-Authors: Enrique Sentandreu, José L. Navarro, José M. SendraAbstract:Juices from the mandarin Clemenules (Citrus clementina Hort. ex Tan.), the tangor Ortanique (Citrus reticulata Blanco × Citrus sinensis Osb.) and the sweet orange Valencia Late (Citrus sinensis) have been industrially squeezed, pasteurized, concentrated and stored under refrigeration (4 °C) and at room temperature (20 °C). After each process, the flavanone-7-O-glycosides (FGs) and fully methoxylated flavones (FMFs) contents as well as total, cumulative fast-Kinetics and cumulative Slow-Kinetics antiradical activities were determined and compared with those from the corresponding fresh hand-squeezed juices. Neither industrial-squeezing, nor pasteurization or concentration significantly affected FGs and FMFs contents and antiradical activities of assayed juices. Storage caused a slight decrease of the FMFs contents but a significant reduction of both soluble hesperidin contents and cumulative fast-Kinetics antiradical activities in all assayed juices. These decreases were dependent on storage temperature. Characteristic values of the varietal characterization parameters, which are derived from the FMFs contents and antiradical activities of fresh hand-squeezed juices, held valid for industrially squeezed, pasteurized and concentrated juices. After storage, however, only the FMFs-derived varietal characterization parameters and cumulative Slow-Kinetics antiradical activity remained valid for the resulting juices.
-
Kinetic Model for the Antiradical Activity of the Isolated p-Catechol Group in Flavanone Type Structures Using the Free Stable Radical 2,2-Diphenyl-1-picrylhydrazyl as the Antiradical Probe
Journal of agricultural and food chemistry, 2007Co-Authors: José M. Sendra, Enrique Sentandreu, José L. NavarroAbstract:The time evolution of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) concentration in four solvents (methanol, ethanol, propanol, and acetonitrile) during its reduction by three flavanones containing an isolated p-catechol group (taxifolin, eriodyctiol, and fustin) as well as the time evolution of the mass spectra of the reaction mixture has been determined by spectrophotometry and liquid mass spectrometry, respectively. In alcoholic solvents the reduction curves consisted of an initial short but fast Kinetics step followed by a longer Slow Kinetics step; in contrast, in acetonitrile the reduction curves completely lacked the Slow Kinetics step. From the results, a kinetic model for the reaction of reduction of the DPPH• by the isolated p-catechol group in flavanone type structures is proposed. According to this model, the p-catechol group rapidly transfers two hydrogen atoms to DPPH•, through a fast rate constant k1, yielding the corresponding o-quinone. Then, the intermediate o-quinone forms an adduct wi...
-
reduction Kinetics of the free stable radical 2 2 diphenyl 1 picrylhydrazyl dpph for determination of the antiradical activity of citrus juices
European Food Research and Technology, 2006Co-Authors: José M. Sendra, Enrique Sentandreu, José L. NavarroAbstract:There is vast epidemiological evidence for the beneficial effects that the consumption of citrus juices exerts on human health. These effects are attributed to their content in substances exhibiting free radical scavenging and antioxidant activities, mainly ascorbic acid, flavonoids, carotenoids and polyphenolic derivatives. This work describes an approximation to the reduction Kinetics of the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH•) by the free radical scavenging activity of juices from sweet orange (Citrus sinensis L.), clementine (Citrus reticulata Blanco) and satsuma (Citrus unshiu K. Marc), as well as the deduction of a kinetic equation to fit the experimental data. This equation contains two contributions. The first contribution accounts for the concentration of DPPH• reduced by the cumulative antiradical activity of those citrus juice components that are capable of fast hydrogen atom transfer (fast-Kinetics), mainly ascorbic acid and some polyphenolic derivatives; the second accounts for the concentration of DPPH• reduced by the cumulative antiradical activity of those citrus juice components that are capable of Slow hydrogen atom transfer (Slow-Kinetics), mainly flavanone-7-O-glycosides and some polyphenolic derivatives. This methodology thus permits the determination of the total antiradical activity of a citrus juice (expressed as molar equivalents of ascorbic acid), as well as the partial contributions of the cumulative antiradical activities (also expressed as molar equivalents of ascorbic acid) due to both fast-Kinetics and Slow-Kinetics.
Alexander S. Balankin - One of the best experts on this subject based on the ideXlab platform.
-
Slow Kinetics of water escape from randomly folded foils
Physical Review E, 2011Co-Authors: Alexander S. Balankin, S. Matías Gutierres, D. Samayoa Ochoa, J. Patiño Ortiz, B. Espinoza Elizarraraz, Claudia Lizbeth Martínez-gonzálezAbstract:Folded configurations of thin matter are ubiquitousin nature [1], ranging from nanoparticle membranes [2]to hand-folded paper [3,4] and fault-related geologicalformations [5]. The physics of folded states display manyinteresting phenomena associated with statistical properties offolding configurations [6,7]. The porosity of randomly foldedsheet can be as large as 99% and decreases with increase ofthe contraction ratio
-
Slow Kinetics of water escape from randomly folded foils.
Physical review. E Statistical nonlinear and soft matter physics, 2011Co-Authors: Alexander S. Balankin, S. Matías Gutierres, D. Samayoa Ochoa, J. Patiño Ortiz, B. Espinoza Elizarraraz, Claudia Lizbeth Martínez-gonzálezAbstract:We study the Kinetics of water escape from balls folded from square aluminum foils of different thickness and edge size. We found that the water discharge rate obeys the scaling relation Q ∝ V{P}(M-M{r}){α} with the universal scaling exponents α=3 ± 0.1, where V{P} is the volume of pore space, M(t) is the actual mass of water in the ball, and M{r} is the mass of residual water. The last is found to be a power-law function of V{P}. The relation of these findings to the fractal geometry of randomly folded matter is discussed.
