1H-NMR Study of the Impact of High Pressure and Thermal Processing on Cell Membrane Integrity of Onions

:  Proton nuclear magnetic resonance (1H‐NMR) relaxometry was used to study the effects of high pressure and thermal processing on membrane permeability and cell compartmentalization, important components of plant tissue texture. High pressure treated onions were subjected to pressure levels from 20...

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Bibliographic Details
Published in:Journal of food science 2010-09, Vol.75 (7), p.E417-E425
Main Authors: Gonzalez, Maria E., Barrett, Diane M., McCarthy, Michael J., Vergeldt, Frank J., Gerkema, Edo, Matser, Ariette M., Van As, Henk
Format: Article
Language:English
Subjects:
Biological and medical sciences
Damage
Exposure
Food industries
Fruit and vegetable industries
Fundamental and applied biological sciences. Psychology
high pressure
Integrity
lactobacillus-plantarum
Magnetic permeability
maize roots
Membranes
mushrooms agaricus-bisporus
NMR
nuclear-magnetic-resonance
Onions
osmotic-stress
pfg-nmr
plant cell integrity
Relaxation time
spin-spin relaxation
Surface layer
Texture
thermal processing
tissue
vacuolar symplast
water diffusion
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Summary::  Proton nuclear magnetic resonance (1H‐NMR) relaxometry was used to study the effects of high pressure and thermal processing on membrane permeability and cell compartmentalization, important components of plant tissue texture. High pressure treated onions were subjected to pressure levels from 20 to 200 MPa at 5 min hold time at initial temperatures of 5 and 20 °C. Thermally treated onions were exposed for 30 min at temperatures from 40 to 90 °C. Loss of membrane integrity was clearly shown by changes in transverse relaxation time (T2) of water at temperatures of 60 °C and above. Destabilization effects on membranes exposed to high pressure were observed at 200 MPa as indicated by T2 measurements and cryo‐scanning electron microscopy (Cryo‐SEM). T2 relaxation successfully discriminated different degrees of membrane damage based on the T2 shift of the vacuolar component. Analyses of the average water self‐diffusion coefficient indicated less restricted diffusion after membrane rupture occurred in cases of severe thermal treatments. Milder processing treatments yielded lower average diffusion coefficients than the controls. 1H‐NMR proved to be an effective method for quantification of cell membrane damage in onions and allowed for the comparison of different food processes based on their impact on tissue integrity.
ISSN:0022-1147
1750-3841
DOI:10.1111/j.1750-3841.2010.01766.x