Thermal Transitions, Mechanical Properties, and Molecular Mobility in Cornflakes as Affected by Water Content
Common cornfl akes (CCF) and sugar - frosted cornfl akes (SCF) were ground and stored at relative humidities (RHs) of 11% - 80% at 25 ° C to achieve a water content (WC) between 5% and 20% dry basis (db). Time - resolved proton nuclear magnetic resonance (TR - 1 H NMR) measuring the spin - spin tran...
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_97808138_v_n_p583_Farroni |
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todo:paper_97808138_v_n_p583_Farroni2023-10-03T16:42:52Z Thermal Transitions, Mechanical Properties, and Molecular Mobility in Cornflakes as Affected by Water Content Farroni, A. Matiacevich, S.B. Guerrero, S. Alzamora, S. Buera, M.P. Common cornflakes (CCF) and sugar-frosted cornflakes (SCF) storage Corn types and CF quality - cornflakes mechanical properties Food products shelf-life stability and thermal properties Thermal transitions and molecular mobility in cornflakes TR-H NMR - solid molecular mobility tempearture dependence analysis TR-H NMR - Time-resolved proton nuclear magnetic resonance Water adsorption by biopolymers - brittle fracture possibility reduction Common cornfl akes (CCF) and sugar - frosted cornfl akes (SCF) were ground and stored at relative humidities (RHs) of 11% - 80% at 25 ° C to achieve a water content (WC) between 5% and 20% dry basis (db). Time - resolved proton nuclear magnetic resonance (TR - 1 H NMR) measuring the spin - spin transverse relaxation time ( T 2 ) was used to determine the mobility of water and solids. T 2 analysis following a single 90 ° pulse (free - induction decay [FID]) was used to evaluate molecular mobility coupled to the solid matrix in the temperature range of 4 ° - 90 ° C. Water mobility was evaluated using a spin - echo (90 ° - ô - 180 ° ) sequence. The FID analysis in both types of cornfl akes (CF) showed a single T 2 . At a WC close to the Guggenheim - Anderson - de Boer (GAB) monolayer value (m 0 = 5% db), the spin - echo analysis showed a short - relaxing T 2 component ( T 2S ) at 25 - 30 ì s that was attributed to the mobility of protons from solids and the most closely associated water molecules. T 2S increased at temperatures above the glass transition temperature ( T g ), indicating higher proton mobility due to plasticization of solids by water. A long - relaxing T 2 component ( T 2L ) was observed at RHs above m 0 and increased as WC increased in the range of 0.4 - 2.5 ms, manifesting the higher mobility of water protons. At very low WC, water acts as an antiplasticizer, but beyond a critical level, the plasticizing effect became evident in mechanical properties. The temperature dependence of water and solid molecular mobility can be analyzed by TR - 1 H NMR. © 2010 Blackwell Publishing. Fil:Farroni, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Matiacevich, S.B. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Guerrero, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Alzamora, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Buera, M.P. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. CHAP info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_97808138_v_n_p583_Farroni |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Common cornflakes (CCF) and sugar-frosted cornflakes (SCF) storage Corn types and CF quality - cornflakes mechanical properties Food products shelf-life stability and thermal properties Thermal transitions and molecular mobility in cornflakes TR-H NMR - solid molecular mobility tempearture dependence analysis TR-H NMR - Time-resolved proton nuclear magnetic resonance Water adsorption by biopolymers - brittle fracture possibility reduction |
| spellingShingle |
Common cornflakes (CCF) and sugar-frosted cornflakes (SCF) storage Corn types and CF quality - cornflakes mechanical properties Food products shelf-life stability and thermal properties Thermal transitions and molecular mobility in cornflakes TR-H NMR - solid molecular mobility tempearture dependence analysis TR-H NMR - Time-resolved proton nuclear magnetic resonance Water adsorption by biopolymers - brittle fracture possibility reduction Farroni, A. Matiacevich, S.B. Guerrero, S. Alzamora, S. Buera, M.P. Thermal Transitions, Mechanical Properties, and Molecular Mobility in Cornflakes as Affected by Water Content |
| topic_facet |
Common cornflakes (CCF) and sugar-frosted cornflakes (SCF) storage Corn types and CF quality - cornflakes mechanical properties Food products shelf-life stability and thermal properties Thermal transitions and molecular mobility in cornflakes TR-H NMR - solid molecular mobility tempearture dependence analysis TR-H NMR - Time-resolved proton nuclear magnetic resonance Water adsorption by biopolymers - brittle fracture possibility reduction |
| description |
Common cornfl akes (CCF) and sugar - frosted cornfl akes (SCF) were ground and stored at relative humidities (RHs) of 11% - 80% at 25 ° C to achieve a water content (WC) between 5% and 20% dry basis (db). Time - resolved proton nuclear magnetic resonance (TR - 1 H NMR) measuring the spin - spin transverse relaxation time ( T 2 ) was used to determine the mobility of water and solids. T 2 analysis following a single 90 ° pulse (free - induction decay [FID]) was used to evaluate molecular mobility coupled to the solid matrix in the temperature range of 4 ° - 90 ° C. Water mobility was evaluated using a spin - echo (90 ° - ô - 180 ° ) sequence. The FID analysis in both types of cornfl akes (CF) showed a single T 2 . At a WC close to the Guggenheim - Anderson - de Boer (GAB) monolayer value (m 0 = 5% db), the spin - echo analysis showed a short - relaxing T 2 component ( T 2S ) at 25 - 30 ì s that was attributed to the mobility of protons from solids and the most closely associated water molecules. T 2S increased at temperatures above the glass transition temperature ( T g ), indicating higher proton mobility due to plasticization of solids by water. A long - relaxing T 2 component ( T 2L ) was observed at RHs above m 0 and increased as WC increased in the range of 0.4 - 2.5 ms, manifesting the higher mobility of water protons. At very low WC, water acts as an antiplasticizer, but beyond a critical level, the plasticizing effect became evident in mechanical properties. The temperature dependence of water and solid molecular mobility can be analyzed by TR - 1 H NMR. © 2010 Blackwell Publishing. |
| format |
CHAP |
| author |
Farroni, A. Matiacevich, S.B. Guerrero, S. Alzamora, S. Buera, M.P. |
| author_facet |
Farroni, A. Matiacevich, S.B. Guerrero, S. Alzamora, S. Buera, M.P. |
| author_sort |
Farroni, A. |
| title |
Thermal Transitions, Mechanical Properties, and Molecular Mobility in Cornflakes as Affected by Water Content |
| title_short |
Thermal Transitions, Mechanical Properties, and Molecular Mobility in Cornflakes as Affected by Water Content |
| title_full |
Thermal Transitions, Mechanical Properties, and Molecular Mobility in Cornflakes as Affected by Water Content |
| title_fullStr |
Thermal Transitions, Mechanical Properties, and Molecular Mobility in Cornflakes as Affected by Water Content |
| title_full_unstemmed |
Thermal Transitions, Mechanical Properties, and Molecular Mobility in Cornflakes as Affected by Water Content |
| title_sort |
thermal transitions, mechanical properties, and molecular mobility in cornflakes as affected by water content |
| url |
http://hdl.handle.net/20.500.12110/paper_97808138_v_n_p583_Farroni |
| work_keys_str_mv |
AT farronia thermaltransitionsmechanicalpropertiesandmolecularmobilityincornflakesasaffectedbywatercontent AT matiacevichsb thermaltransitionsmechanicalpropertiesandmolecularmobilityincornflakesasaffectedbywatercontent AT guerreros thermaltransitionsmechanicalpropertiesandmolecularmobilityincornflakesasaffectedbywatercontent AT alzamoras thermaltransitionsmechanicalpropertiesandmolecularmobilityincornflakesasaffectedbywatercontent AT bueramp thermaltransitionsmechanicalpropertiesandmolecularmobilityincornflakesasaffectedbywatercontent |
| _version_ |
1807319195324514304 |