Transport properties of fermentation metabolites inside 'Conference' pear fruit

- Diffusivity of ethanol, acetaldehyde and ethyl acetate in pear tissue was measured.
- Measured values corresponded well with those computed from a microscale model.
- Cell membrane limits diffusion of fermentation metabolites in cortex tissue.
- Permeation through the epidermis was related to lenticel density.

Ethanol, acetaldehyde and ethyl acetate are the major fermentation metabolites in 'Conference' pear fruit under severe hypoxic or anoxic storage conditions. Predicting diffusion of the fermentation metabolites in fruit tissue will allow to understand the accumulation of the harmful fermentation metabolites under anoxic conditions and to predict their release during reoxygenation after anoxia. In this paper, the diffusivity of fermentation metabolites of pear fruit tissue was computed using a multiscale diffusion model and experimentally validated. The effect of temperature on the diffusion of the metabolites inside the fruit was assessed. Simulation results revealed that the cell membrane is an important barrier to diffusion of fermentation metabolites in cortex tissue. The diffusivity of fermentation metabolites across the epidermis was much lower than that of cortex tissue, and was highly affected by the density of lenticels. The diffusivities of fermentation metabolites increased with increasing temperature in both cortex and epidermis tissues.