Effect of immersion and turgor pressure change on mechanical properties of pumpkin (Cucumis moschata, Duch.)

Mesocarp raw tissue of a pumpkin (Cucumis moschata, Duch.) popularly known in Argentina as 'calabacita criolla' was rheologically characterized by large and small deformations after a stepwise adjustment of its turgor pressure to determine the relative contributions of turgor pressure, cel...

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Autores principales: Pla, M.D.E., Delbon, M., Rojas, A.M., Gerschenson, L.N.
Formato: JOUR
Materias:
Dynamic moduli
Firmness
Pumpkin
Relaxation force
Structure
Turgor pressure
Cucumis
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00225142_v86_n15_p2628_Pla
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_00225142_v86_n15_p2628_Pla2023-10-03T14:33:33Z Effect of immersion and turgor pressure change on mechanical properties of pumpkin (Cucumis moschata, Duch.) Pla, M.D.E. Delbon, M. Rojas, A.M. Gerschenson, L.N. Dynamic moduli Firmness Pumpkin Relaxation force Structure Turgor pressure Cucumis Mesocarp raw tissue of a pumpkin (Cucumis moschata, Duch.) popularly known in Argentina as 'calabacita criolla' was rheologically characterized by large and small deformations after a stepwise adjustment of its turgor pressure to determine the relative contributions of turgor pressure, cell wall (CW) and middle lamella (ML) to the mechanical behavior. Examinations using light microscopy (LM) and transmission electron microscopy (TEM) were performed in order to explain the textural behavior observed. In general, firmness at failure, residual relaxation force and dynamic moduli increased with turgor pressure. For all the hypotonic solutions (polyethylene glycol 400 (PEG) concentrations lower than 250 mol m-3) a gain of tissue weight was observed, a trend that indicated a null occurrence of cell bursting as confirmed by observations using LM and TEM of undamaged cell membranes with swelled cytoplasms. However, no significative change in relative volume was detected for tissue equilibrated in PEG with concentrations of 0-130 mol m-3, probably due to the resistance of CW to further elongation. Peaks of failure were observed during compression for tissue equilibrated under all osmotic conditions and their presence was associated with CW integrity. Plasmolysed tissue did not show a residual force at infinite time of relaxation. Incipient plasmolysis was better detected by rheological studies than by volume change and it was confirmed by LM. Significant correlations were obtained between residual relaxation force and either storage moduli or phase shift angle, revealing that relaxation out of the linear viscoelasticity range and dynamic assays provide analogous information concerning tissue behavior. © 2006 Society of Chemical Industry. Fil:Pla, M.D.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Rojas, A.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Gerschenson, L.N. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00225142_v86_n15_p2628_Pla
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Dynamic moduli
Firmness
Pumpkin
Relaxation force
Structure
Turgor pressure
Cucumis
spellingShingle Dynamic moduli
Firmness
Pumpkin
Relaxation force
Structure
Turgor pressure
Cucumis
Pla, M.D.E.
Delbon, M.
Rojas, A.M.
Gerschenson, L.N.
Effect of immersion and turgor pressure change on mechanical properties of pumpkin (Cucumis moschata, Duch.)
topic_facet Dynamic moduli
Firmness
Pumpkin
Relaxation force
Structure
Turgor pressure
Cucumis
description Mesocarp raw tissue of a pumpkin (Cucumis moschata, Duch.) popularly known in Argentina as 'calabacita criolla' was rheologically characterized by large and small deformations after a stepwise adjustment of its turgor pressure to determine the relative contributions of turgor pressure, cell wall (CW) and middle lamella (ML) to the mechanical behavior. Examinations using light microscopy (LM) and transmission electron microscopy (TEM) were performed in order to explain the textural behavior observed. In general, firmness at failure, residual relaxation force and dynamic moduli increased with turgor pressure. For all the hypotonic solutions (polyethylene glycol 400 (PEG) concentrations lower than 250 mol m-3) a gain of tissue weight was observed, a trend that indicated a null occurrence of cell bursting as confirmed by observations using LM and TEM of undamaged cell membranes with swelled cytoplasms. However, no significative change in relative volume was detected for tissue equilibrated in PEG with concentrations of 0-130 mol m-3, probably due to the resistance of CW to further elongation. Peaks of failure were observed during compression for tissue equilibrated under all osmotic conditions and their presence was associated with CW integrity. Plasmolysed tissue did not show a residual force at infinite time of relaxation. Incipient plasmolysis was better detected by rheological studies than by volume change and it was confirmed by LM. Significant correlations were obtained between residual relaxation force and either storage moduli or phase shift angle, revealing that relaxation out of the linear viscoelasticity range and dynamic assays provide analogous information concerning tissue behavior. © 2006 Society of Chemical Industry.
format JOUR
author Pla, M.D.E.
Delbon, M.
Rojas, A.M.
Gerschenson, L.N.
author_facet Pla, M.D.E.
Delbon, M.
Rojas, A.M.
Gerschenson, L.N.
author_sort Pla, M.D.E.
title Effect of immersion and turgor pressure change on mechanical properties of pumpkin (Cucumis moschata, Duch.)
title_short Effect of immersion and turgor pressure change on mechanical properties of pumpkin (Cucumis moschata, Duch.)
title_full Effect of immersion and turgor pressure change on mechanical properties of pumpkin (Cucumis moschata, Duch.)
title_fullStr Effect of immersion and turgor pressure change on mechanical properties of pumpkin (Cucumis moschata, Duch.)
title_full_unstemmed Effect of immersion and turgor pressure change on mechanical properties of pumpkin (Cucumis moschata, Duch.)
title_sort effect of immersion and turgor pressure change on mechanical properties of pumpkin (cucumis moschata, duch.)
url http://hdl.handle.net/20.500.12110/paper_00225142_v86_n15_p2628_Pla
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