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Published on: May 5, 2017
PFG-NMR study for evaluating freezing damage to onion tissue
Hiroko Ando1, Mika Fukuoka, Osato Miyawaki
1Department of Biological and Environmental Engineering, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
Bioscience, Biotechnology, and Biochemistry
|June 9, 2009
Summary
Freeze-thawing significantly increases water permeability in onion tissue by damaging cell membranes, as detected by pulsed-field gradient nuclear magnetic resonance (PFG-NMR), even when light microscopy shows no visible tissue damage.
Area of Science:
- Plant physiology
- Biophysics
- Food science
Background:
- Freeze-thawing is a common process affecting vegetable tissues.
- Understanding cellular damage mechanisms is crucial for food preservation.
- Water transport properties are key indicators of cellular integrity.
Purpose of the Study:
- To quantify the effect of freeze-thawing on water permeability in onion tissue.
- To investigate the cellular structures affected by freeze-thaw cycles.
- To compare the sensitivity of PFG-NMR and light microscopy in detecting freeze-thaw damage.
Main Methods:
- Water permeability was measured using pulsed-field gradient nuclear magnetic resonance (PFG-NMR).
- Light microscopy was employed to visually assess tissue integrity.
- Water diffusion coefficients and permeability were calculated for fresh and freeze-thawed onion tissues.
Main Results:
- Water diffusion in fresh onion tissue was restricted, with a permeability of 6.99 x 10(-6) m/s.
- Freeze-thawing significantly increased water permeability to 2.85 x 10(-5) m/s.
- PFG-NMR detected altered water diffusion, while light microscopy showed no significant structural damage.
Conclusions:
- Freeze-thawing primarily damages vegetable tissues by disrupting cell membranes, not cell walls.
- PFG-NMR is a sensitive technique for detecting sub-visual cellular damage caused by freeze-thawing.
- Cell membrane integrity is critical for regulating water transport in plant tissues.
