title: PFG-NMR study for evaluating freezing damage to onion tissue.
abstract: We assessed the damage to onion tissue due to freeze-thawing as the water permeability determined by using PFG-NMR and light microscopy. The water diffusion in fresh onion tissue was restricted due to cellular barriers, and the estimated water permeability was 6.99 x 10(-6)m/s. The water diffusion became considerably less restricted after freeze-thawing; the convergent value for the restricted diffusion coefficient increased and the water permeability significantly increased to 2.85 x 10(-5) m/s. While NMR could detect a distinct change in the diffusion behavior of water molecules in freeze-thawed tissue, light microscopy revealed no significant tissue damage. These results suggest that freeze-thawing damaged the vegetable tissues primarily through destruction of the cell membrane rather than the cell wall.
authors.affiliation: Department of Biological and Environmental Engineering, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Ando
authors.forename: Mika
authors.initials: M
authors.lastname: Fukuoka
authors.forename: Osato
authors.initials: O
authors.lastname: Miyawaki
authors.forename: Manabu
authors.initials: M
authors.lastname: Watanabe
authors.forename: Toru
authors.initials: T
authors.lastname: Suzuki
mesh_terms: D005615:Freezing; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D019697:Onions; D010539:Permeability; D014867:Water
chemical_list: D014867:Water