Apple and pear are stored under controlled atmosphere conditions. Too low internal oxygen (O2) or too high carbon dioxide (CO2) concentrations may lead to storage disorders such as browning. The internal gas concentration is mainly determined by the fruit’s gas exchange properties, which depend on the structural arrangement of fruit cells and tissues. We used (for the first time) submicron synchrotron X-ray computed tomography (CT) to investigate how pome fruit tissues are spatially organized to facilitate or impede gas exchange. The experiments were conducted on beamline ID19 at the European Synchrotron Radiation Facility (ESRF, Grenoble, France), i.e., on a long (150 m) imaging beamline where the spatial coherence of the beam is particularly large (transverse coherence length in the order of 100 μm). The method allows for imaging in phase contrast, which, as opposed to absorption contrast, is a powerful method to distinguish, in absorbing materials, phases with very similar X-ray attenuation but different electron densities. In this study, it is efficiently used for edge detection at cell-cell interfaces where absorption images have insufficient contrast. We visualized 3-D networks of gas-filled intercellular spaces in two fruits, apple (cv. Jonagold) and pear (cv. Conference), that provide the main routes for exchange of O2 and CO2 with the environment, using absorption as well as phase contrast synchrotron X-ray CT at a pixel resolution ranging from 0.7 to 5.0 μm. The differences in void dimensions and connectivity between tissues and fruits helped explain imbalances in gas exchange that may result in internal disorders and structural degradation. We also showed that tomography with synchrotron radiation operated in phase-contrast mode and is able to visualize the 3-D geometry of voids, cells, and cell walls of biological tissues with high water content at submicron voxel resolution. In terms of facilitating gas exchange, the network pattern of the voids indicated a large size and volume fraction difference with the unconnected void structure found in apple. The partial breakdown of such networks would quickly lead to an internal gas imbalance leading to internal disorders. The achievement of high-resolution 3-D microstructural properties of cells and tissues is an important breakthrough for the study of gas exchange mechanisms in fruits stored under controlled atmosphere conditions. In addition to gas exchange, the results will benefit the study of water relations and mechanics of foods.
Synchrotron Radiation Fruit Tissue Pear Fruit Pome Fruit Internal Disorder
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The K.U. Leuven Interfaculty Council for Development Co-operation (IRO), the K.U. Leuven Research Council (project OT-08023), the Fund for Scientific Research (project G.06.03.08), and the Institute for the Promotion of Innovation by Science and Technology in Flanders (projects IWT-060720 and IWT-050633) are gratefully acknowledged for financial support. Pieter Verboven is Fellow of the Industrial Research Fund of the K.U. Leuven. The results were obtained with a beamtime project of the European Synchrotron Radiation Facility in Grenoble, France (experiment MA222).
Babin P, Della Valle G, Dendievel R, Lassoued N, Salvo L (2005) Mechanical properties of bread crumbs from tomography based finite element simulations. J Mater Sci 40:5867–5873CrossRefGoogle Scholar
Cloetens P, Ludwig W, Baruchel J, Van Dyck D, Van Landuyt J, Guigay JP, Schlenker M (1999) Holotomography: quantitative phase tomography with micrometer resolution using hard synchrotron radiation x rays. Appl Phys Lett 75:2912–2914CrossRefGoogle Scholar
Cloetens P, Mache R, Schlenker M, Lerbs-Mache S (2006) Quantitative phase tomography of Arabidopsis seeds reveals intercellular void network. Proc Natl Acad Sci USA 103:14626–14630CrossRefGoogle Scholar
Davis TJ, Gao D, Gureyev TE, Stevenson AW, Wilkins SW (1995) Phase contrast imaging of weakly absorbing materials using hard X-rays. Nature 373:595–598CrossRefGoogle Scholar
Ho Q, Verboven P, Mebatsion H, Verlinden B, Vandewalle S, Nicolaï B (2009) Microscale mechanisms of gas exchange in fruit tissue. New Phytol 182:163–174CrossRefGoogle Scholar
Kim SA, Punshon A, Lanzirotti A, Li L, Alonso JM, Ecker JR, Kaplan J, Guerinot ML (2006) Localization of iron in Arabidopsis seed requires the vacuolar membrane transporter VIT1. Science 314:1295–1298CrossRefGoogle Scholar
Kuroki S, Oshita S, Sotome I, Kawagoe Y, Seo Y (2004) Visualization of 3-D network of gas-filled intercellular spaces in cucumber fruit after harvest. Postharvest Biol Technol 33:255–262CrossRefGoogle Scholar
Lammertyn J, Dresselaers T, Van Hecke P, Jancsok P, Wevers M, Nicolaï BM (2003) Magn Reson Imaging 21:805–815CrossRefGoogle Scholar
Léonard A, Blacher S, Nimmol C, Devahastin S (2008) Effect of far-infrared radiation assisted drying on microstructure of banana slices: an illustrative use of X-ray microtomography in microstructural evaluation of a food product. J Food Eng 85:154–162CrossRefGoogle Scholar
Lim KS, Barigou M (2004) X-ray micro-computed tomography of aerated cellular food products. Food Res Int 37:1001–1012CrossRefGoogle Scholar
Mebatsion HK, Verboven P, Ho QT, Mendoza F, Verlinden BE, Nguyen TA, Nicolaï BM (2006) Modeling fruit microstructure using novel ellipse tessellation algorithm. CMES-Comp Model Eng 14:1–14Google Scholar
Mebatsion H, Verboven P, Ho Q, Verlinden B, Nicolaï B (2008a) Modelling fruit (micro) structures, why and how? Trends Food Sci Technol 19:59–66CrossRefGoogle Scholar
Mebatsion HK, Verboven P, Jancsók PT, Ho QT, Verlinden B, Nicolaï BM (2008b) Modeling 3-D fruit tissue microstructure using a novel ellipsoid tessellation algorithm. CMES-Comp Model Eng 29:137–149Google Scholar
Mebatsion HK, Verboven P, Melese Endalew A, Billen J, Ho QT, Nicolaï BM (2009) A novel method for 3-D microstructure modeling of pome fruit tissue using synchrotron radiation tomography images. J Food Eng 93(2):141–148CrossRefGoogle Scholar
Mendoza F, Verboven P, Mebatsion HK, Kerckhofs G, Wevers M, Nicolaï B (2007) Three-dimensional pore space quantification of apple tissue using X-ray computed microtomography. Planta 226:559–570CrossRefGoogle Scholar
Thurner P, Muller R, Raeber G, Sennhauser U, Hubbell J (2005) 3D Morphology of cell cultures: a quantitative approach using micrometer synchrotron light tomography. Microsc Res Tech 66:289–298CrossRefGoogle Scholar
Veraverbeke EA, Van Bruaene N, Van Oostveldt P, Nicolaï BM (2001) Non destructive analysis of the wax layer of apple (Malus domestica Borkh.) by means of confocal laser scanning microscopy. Planta 213:525–533CrossRefGoogle Scholar
Verboven P, Kerckhofs G, Mebatsion H, Ho Q, Temst K, Wevers M, Cloetens P, Nicolaï B (2008) Three-dimensional gas exchange pathways in pome fruit characterized by synchrotron X-ray computed tomography. Plant Physiol 147:518–527CrossRefGoogle Scholar
Westneat MW, Betz O, Blob RW, Fezzaa K, Cooper WJ, Lee W-K (2003) Tracheal respiration in insects visualized with synchrotron X-ray imaging. Science 299:558–560CrossRefGoogle Scholar