A novel method to measure gas diffusion properties of pear tissue and skin
was developed. In a temperature and pressure controlled system, a diffusion
cell was attached to a polarographic oxygen electrode to measure gas diffu
sivity. A dynamic finite element model based on simultaneous gas diffusion
and respiration for pear slices and pear skin was developed. The average ex
perimentally determined values for oxygen diffusivity in tissue and skin we
re, respectively, 1.71 x 10(-9) m(2) s(-1) and 2.84 x 10(-10) m(2) s(-1). T
he mean estimated tissue and skin respiration values did not differ statist
ically, at a 5% level of significance, from the mean respiration values obt
ained in an independent traditional respiration experiment. If the oxygen c
onsumption and the oxygen diffusivity needed to be estimated accurately and
simultaneously from one experiment, the experiment typically lasted 15 h.
The duration of the diffusion measurement could be reduced to 3 h, when the
respiration characteristics were measured in a separate experiment. Monte-
Carlo simulations were performed to calculate the variability due to biolog
ical variation of oxygen transport and consumption in slices of pear tissue
covered with skin. (C) 2001 Elsevier Science B.V. All rights reserved.