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Mathematical modelling of gas exchanges in film-wrapped cucumbers

Cazier, Jean-Baptiste (2000). Mathematical modelling of gas exchanges in film-wrapped cucumbers. Diss. (sammanfattning/summary) Alnarp : Sveriges lantbruksuniv., Acta Universitatis agriculturae Sueciae. Agraria, 1401-6249 ; 251
ISBN 91-576-5763-7
[Doctoral thesis]

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Abstract

Preserving cucumber (Cucumis sativus L.) quality by film wrapping is common practice in Sweden. Nevertheless, no theoretical background is available to explain the choice of the films currently used. A better understanding of the phenomena involved in preserving quality by film wrapping of greenhouse cucumbers can be achieved by means of mathematical modelling of the gas exchanges. An apparatus controlled by a computer was developed to measure gas exchanges in fresh produce. The transpiration and respiration rates evolution of film-wrapped cucumbers was investigated by emulation of the different gas levels present in the packages. A modification of this set-up was used to study the effect of various films on preserving the quality of cucumbers. In further experiments, the influence of surrounding conditions on the respective role of cuticular and stomatal permeability in the gas exchanges was investigated. It appeared that a reduction of moisture loss was of highest importance in the preservation of cucumber mass. Both respiration and transpiration rates were strongly influenced by the surrounding temperature and relative humidity. The transpiration rate under constant conditions decreased rapidly resulting in severe loss of quality directly after harvest. Film wrapping reduced significantly the effect of surrounding temperature and relative humidity. Moreover the introduction of a modified atmosphere inside the packages reduced both respiration and transpiration rates. However, the appearance of water vapour condensation inside the film favours microbial hazard. Based on data from the experiments and known physiological and physical phenomena, a mathematical model of the gas exchanges was designed. Two versions were derived to study the gas concentration in a jar corresponding to the experiments, as well as giving a closer insight into what happens between the epidermis and a film. These models take into account many parameters relative to the cucumber such as permeability, degree of opening or distribution of stomata. Furthermore, film properties such as thickness, size of perforation or permeability could also be investigated. Simulations from the implementation of the mathematical model enable theoretical studies of the importance of those parameters when direct measurements are not possibl

Authors/Creators:Cazier, Jean-Baptiste
Title:Mathematical modelling of gas exchanges in film-wrapped cucumbers
Year of publishing :January 2000
Volume:251
Number of Pages:22
Papers/manuscripts:
NumberReferences
ALLI. Cazier, J.-B., Nilsson, T., Gekas, V. 2000. Monitoring respiration and transpiration of fresh horticultural produce. Journal of Food Engineering. Submitted II. Cazier, J.-B., Nilsson, T., Gekas, V. 2000. Effect of Film Wrapping on Quality of Greenhouse Cucumbers. Journal of Agricultural Engineering Research. Submitted III. Cazier, J.-B., Gekas V. 2001. Water activity and its prediction: a review. International Journal of Food Properties. In press IV. Cazier, J.-B., Gekas, V., Nilsson, T. 2000. Epidermis influence on the gas exchanges around a produce. International Journal of Food Properties. Submitted V. Cazier, J.-B., Gekas, V., Nilsson, T. 2000. Mathematical modelling of water vapour exchange through stomata and microperforated packaging film. Applied Mathematical Modelling. Submitt
Place of Publication:Alnarp
Associated Programs and Other Stakeholders:Z - SLU - Libray > Odla mera
ISBN for printed version:91-576-5763-7
ISSN:1401-6249
Language:English
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:Q Food science > Q02 Food processing and preservation
Subjects:Not in use, please see Agris categories
Agrovoc terms:controlled atmosphere storage, cucumbers, gas exchange, mathematical models, plastic film covers, postharvest decay, storage, gas exchange
Keywords:Finite element method, modified atmosphere packaging, partial differential equation, respiration, transpiration, water activity
ID Code:8
Department:(NL, NJ) > Institutionen för växtvetenskap
Deposited By: Staff Epsilon
Deposited On:23 Apr 2002 00:00
Metadata Last Modified:22 Mar 2015 15:11

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