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RESEARCH PRODUCT
Firming of fruit tissues by vacuum infusion of pectin methylesterase: Visualisation of enzyme action
Françoise HuberAnne GuilleminMarc LahayeCorinne RondeauFabienne GuillonEric BadelRémi SaurelMarie-françoise DevauxPascal Degraevesubject
0106 biological sciencesfood.ingredientPectinPectin methylesterasechemistry.chemical_elementCalciumPolysaccharide01 natural sciencescomplex mixturesAnalytical ChemistryFruit firmnessCell wallVacuum-impregnation0404 agricultural biotechnologyfood010608 biotechnology[SDV.IDA]Life Sciences [q-bio]/Food engineeringchemistry.chemical_classificationRIGIDITE MOLECULAIRE04 agricultural and veterinary sciencesGeneral MedicinePenetration (firestop)PECTIN METHYLESTERASE 040401 food sciencePectinPectinesteraseEnzymechemistryBiochemistryBiophysicsIntracellularFood Sciencedescription
; Apple pieces were vacuum-impregnated with either a pectin methylesterase (PME) and calcium solution or with water prior to pasteurization. Pasteurized apple pieces impregnated with PME and calcium showed a significantly higher firmness. Moreover, solid state C-13 NMR spectroscopy of apple cell wall residues revealed an increase of their molecular rigidity. Exogenous PME addition involved a decrease from 82% to 45% of apple pectin degree of methyl-esterification. Microscopic observations of apple slices immunolabelled with antibodies specific for pectins showed that (i) demethyl-esterification was more intense in the cell wall region lining intercellular spaces (demonstrating a key role for these intercellular channels in the enzyme penetration in the tissue during vacuum-infusion) and that (ii) the number of calcium-dimerized deesterified homogalacturonan chains increased. The results corroborate the hypothesis that vacuum-impregnated PME action liberates free carboxyl groups along pectin chains that could interact with calcium, increasing the rigidity of pectins and finally the mechanical rigidity of apple tissue. (C) 2007 Elsevier Ltd. All rights reserved.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2008-01-01 |