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Applied research
Application of fundamental research to problems in agro-food sector
Application areasEgg quality and incubation (Josse De Baerdemaeker)
Food quality (Jeroen Lammertyn)
Predictive microbiology and risk analysis (Annemie
Geeraerd)
Agrofood process design (Josse De Baerdemaeker)
Postharvest technology (Bart Nicolaï)
Precision mechanics (Herman Ramon)
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0.00E+00
1.00E-08
2.00E-08
3.00E-08
4.00E-08
5.00E-08
6.00E-08
0.15 0.17 0.19 0.21 0.23
DO
2(m
2/s)
VmO2 (mmol/m3.s)
Jonagold
Conference
Cameo
Kanzi
Biophysics
Biology
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TemperatureO2
CO2
Full factorial screening design23+1=9 combinations
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Full factorial response surface design33=27 combinations
TemperatureO2
CO2
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BIOSYST-MeBioS www.biw.kuleuven.be
Multiscale modelling of gas transport in plant tissue
Bart M. Nicolaï
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Continuum model
States: O2, CO2 and N2
Enzyme kinetics: Michaëlis-MentenInhibition by CO2
Vmax dependent on temperature according to Arrhenius
Transport: diffusion + permeation
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2
2 2
2
OO O
O
C Lflux D D fluxL C
Δ= ⇒ =
Δ
L
5% O2
15% O2
Brown, 1827; Fick,1855; Einstein,1905.Ho et al. Postharvest Biol Technol, 41:113-120.
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2
2 2
2
OO O
O
C Lflux D D fluxL C
Δ= ⇒ =
Δ
L
5% O2
15% O2
Brown, 1827; Fick,1855; Einstein,1905.Ho et al. Postharvest Biol Technol, 41:113-120.
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Lammertyn et al. 2003. Postharvest Biol Technol 30: 29-42Ho et al. 2006. J. Exp. Bot. 57, 4215-4224.Ho et al. 2008. PLoS Computational Biology 4(3): e1000023 doi:10.1371/journal.pcbi.1000023
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Validation: gas partial pressure in jar with pear
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ProblemsFit reasonable but not perfectApparent model parametersSimulations do not provide direct information about gas related disorders
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ProblemsFit reasonable but not perfectApparent model parametersSimulations do not provide direct information about gas related disorders
Multiscale model
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Multiscale modelling
1 cm 100 μm 10 μm 100 nm
Fruit Cell Membrane Plasmodesmaton
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2
2 2
2
OO O
O
C Lflux D D fluxL C
Δ= ⇒ =
Δ
L
5% O2
15% O2
L
5% O2
15% O2
2-D Microscale model
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Light microscopy image and ellipse tesselation of apple cortex tissueMebatsion et al. (2008) Computational Modeling in Engineering and Sciences 14, 1-14; Trends in Food Science & Technology 19(2), 59-66
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Microscale O2 transport in apple cortex tissueHo et al. (2008) New Phytologist, 182: 163–174
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Diffusivity (m2 s-1):
Cell 2.01×10-9
Air 1.6×10-5
Cell wall 4.25×10-9
⇒ Cell wall porous ?
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Diffusivity (m2 s-1):
Cell 2.01×10-9
Air 1.6×10-5
Cell wall 4.25×10-9
⇒ Cell wall porous ?
Plant Cell wall Albert et al., 1994)
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Flatland (1884)E. A. Abbot
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X-Ray micro computed tomography (MTM K.U.Leuven)
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Micro CT image of apple parenchyma tissue Mendoza et al., Planta 226, 559-570
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European Synchrotron Radiation Facility (ESRF)
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3-D rendering of the void network of apple (A) and pear (B) fruit cortexVerboven et al. Plant Physiol. 2008;147:518-527
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3-D microscale modelModel:
Pore, cell: Fick’s second law of diffusionIntracellular respiration: Michaelis Menten Kinetics Interface between gas and liquid phase: Henry’ s law
Finite volume discretisation~ 2 106 or 4 106 control volumesAlgebraic multigrid solver
Solution on cluster computerAMD Opteron cluster16 Gb RAM
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Epidermis and sub-epidermis
E1 E2
mol m-3
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Parenchyma tissue
mol m-3
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Vascular bundles regionmol m-3
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Simulation Experiment Reference
Epidermis / 8.5×10‐10―1.9×10‐10 1.9×10‐10―3.3×10‐10 Ho et al. (2006)
hypodermis Schotsmans et al. (2003)
Cortex parenchyma 3.6×10‐10―2.7×10‐8 2.8×10‐10 ―5.6 ×10‐10 Ho et al. (2006)
Schotsmans et al. (2003)
Brachysklereids 1.48×10‐10
Vascular tissue 3.45×10‐8
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Conclusions
O2 transport is mainly through the intercellular space3D modelling necessaryMacroscopic diffusivity depends to a large extent on microstructureMeasured and predicted diffusion coefficients are in the same range
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Outlook
Smaller scales ?Coupling with metabolic pathway modelsTransport of other species (water, ethanol, ethylene)ValidationVirtual plant
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AcknowledgementsWendy SchotsmansJeroen LammertynFernando MendozaQuang Tri HoPieter VerbovenHibru MebatsionBert VerlindenGreet KerckhofsTuan PhamNguyen Trung AnhNico ScheerlinckJustyna CybulskaStijn Verlaak