Chemical and biochemical changes of pumpkin (Cucumis moschata, Duch) tissue in relation to osmotic stress

Chemical and biochemical changes of pumpkin (Cucumis moschata, Duch) tissue in relation to osmotic stress were studied and related to tissue textural behavior. Turgor pressure of raw tissue was adjusted by immersion in hypotonic (0.0 mol m-3), isotonic (250 mol m-3) and plasmolyzing (1050 mol m-3) b...

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Autores principales: De Escalada Pla, M.F., Ponce, N.M., Wider, M.E., Stortz, C.A., Rojas, A.M., Gerschenson, L.N.
Formato: JOUR
Materias:
Enzymes
Pectins
Polysaccharides
Pumpkin
Turgor pressure
Cucumis
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00225142_v85_n11_p1852_DeEscaladaPla
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_00225142_v85_n11_p1852_DeEscaladaPla2023-10-03T14:33:32Z Chemical and biochemical changes of pumpkin (Cucumis moschata, Duch) tissue in relation to osmotic stress De Escalada Pla, M.F. Ponce, N.M. Wider, M.E. Stortz, C.A. Rojas, A.M. Gerschenson, L.N. Enzymes Pectins Polysaccharides Pumpkin Turgor pressure Cucumis Chemical and biochemical changes of pumpkin (Cucumis moschata, Duch) tissue in relation to osmotic stress were studied and related to tissue textural behavior. Turgor pressure of raw tissue was adjusted by immersion in hypotonic (0.0 mol m-3), isotonic (250 mol m-3) and plasmolyzing (1050 mol m-3) buffered (20 mol m-3 potassium phosphate, pH 6.8) solutions of poly(ethylene glycol) 400 (PEG). It was found that a substantial proportion of polysaccharides located in the cell wall (CW)-middle lamellae (ML) of studied tissue was water extractable. This proportion decreased when CW-stretch increased. Ionically bound peroxidase (POX) presented an increased activity in swollen and isotonic tissue, probably associated to oxidative cross-linking of extensin located in the CW of this tissue, as a response to stress promoted by cut, immersion and turgor pressure change. The resistance of CW to elongation when equilibrated in hypotonic medium, might be ascribed to reinforcement of the CW by the oxidative cross-linking of extensin, with simultaneous formation of pectin-in-extensin entanglements. Plasmolyzed tissue where CW is relaxed, showed pectin-rhamnogalacturonan degradation. The water-soluble fraction (WSF) was shown to be a negative function of CW stretching and infinite force of relaxation. © 2005 Society of Chemical Industry. Fil:De Escalada Pla, M.F. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Stortz, C.A. 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_v85_n11_p1852_DeEscaladaPla
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Enzymes
Pectins
Polysaccharides
Pumpkin
Turgor pressure
Cucumis
spellingShingle Enzymes
Pectins
Polysaccharides
Pumpkin
Turgor pressure
Cucumis
De Escalada Pla, M.F.
Ponce, N.M.
Wider, M.E.
Stortz, C.A.
Rojas, A.M.
Gerschenson, L.N.
Chemical and biochemical changes of pumpkin (Cucumis moschata, Duch) tissue in relation to osmotic stress
topic_facet Enzymes
Pectins
Polysaccharides
Pumpkin
Turgor pressure
Cucumis
description Chemical and biochemical changes of pumpkin (Cucumis moschata, Duch) tissue in relation to osmotic stress were studied and related to tissue textural behavior. Turgor pressure of raw tissue was adjusted by immersion in hypotonic (0.0 mol m-3), isotonic (250 mol m-3) and plasmolyzing (1050 mol m-3) buffered (20 mol m-3 potassium phosphate, pH 6.8) solutions of poly(ethylene glycol) 400 (PEG). It was found that a substantial proportion of polysaccharides located in the cell wall (CW)-middle lamellae (ML) of studied tissue was water extractable. This proportion decreased when CW-stretch increased. Ionically bound peroxidase (POX) presented an increased activity in swollen and isotonic tissue, probably associated to oxidative cross-linking of extensin located in the CW of this tissue, as a response to stress promoted by cut, immersion and turgor pressure change. The resistance of CW to elongation when equilibrated in hypotonic medium, might be ascribed to reinforcement of the CW by the oxidative cross-linking of extensin, with simultaneous formation of pectin-in-extensin entanglements. Plasmolyzed tissue where CW is relaxed, showed pectin-rhamnogalacturonan degradation. The water-soluble fraction (WSF) was shown to be a negative function of CW stretching and infinite force of relaxation. © 2005 Society of Chemical Industry.
format JOUR
author De Escalada Pla, M.F.
Ponce, N.M.
Wider, M.E.
Stortz, C.A.
Rojas, A.M.
Gerschenson, L.N.
author_facet De Escalada Pla, M.F.
Ponce, N.M.
Wider, M.E.
Stortz, C.A.
Rojas, A.M.
Gerschenson, L.N.
author_sort De Escalada Pla, M.F.
title Chemical and biochemical changes of pumpkin (Cucumis moschata, Duch) tissue in relation to osmotic stress
title_short Chemical and biochemical changes of pumpkin (Cucumis moschata, Duch) tissue in relation to osmotic stress
title_full Chemical and biochemical changes of pumpkin (Cucumis moschata, Duch) tissue in relation to osmotic stress
title_fullStr Chemical and biochemical changes of pumpkin (Cucumis moschata, Duch) tissue in relation to osmotic stress
title_full_unstemmed Chemical and biochemical changes of pumpkin (Cucumis moschata, Duch) tissue in relation to osmotic stress
title_sort chemical and biochemical changes of pumpkin (cucumis moschata, duch) tissue in relation to osmotic stress
url http://hdl.handle.net/20.500.12110/paper_00225142_v85_n11_p1852_DeEscaladaPla
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