Temperature dependency of gas diffusivity and skin resistance of japanese pear ('oushuu') based on the fruit's true 3D geometry

Abstract

'Oushuu' is a late ripening cultivar of Pyrus pyrifolia. In the present study some of the physical and gas transport properties of this cultivar have been measured or estimated from a mathematical model written with COMSOL Multiphysics 4.2a, using the exact 3D geometry of the pear obtained with NextEngine 3D laser scanner. The experiments were done at 5, 15 and 25?. The model was validated by conducting experiments to measure the internal concentration at different points of the fruit and comparing them with the model results. The model was shown to be successful in predicting the internal gas concentrations. Gas diffusivity of 'Oushuu' at 5? was found to be 5.97 × 10-7 m2/s and its skin resistance to be 4.04 × 105 s/m. However the results at higher temperatures seem to be less accurate. As a result, a co-diffusion model was used to estimate the gas diffusivity and skin resistance of 'Oushuu' at higher temperatures. Copyright © 2014, Japanese Society for Food Science and Technology.