Optical Coherence Tomography – Developing Tools to interrogate the skin of fruits and vegetable

Professor Adrian Podoleanu, Applied Optics Group, University of Kent

Dr. Julien Lecourt, EMR, head of viticulture, wine research
on Divico grapes

Project Summary

As a barrier to moisture loss, the epidermis and epicuticular waxes play a critical role in maintaining cell turgor while providing structural support combined with plasticity to respond to pressures associated with fruit expansion during development and ripening.

After harvest moisture loss through epidermal cells and the stem scar cause epidermal cells to go from rounded and turgid to flat and flaccid, accelerating movement of water vapour through the apoplast. Oxidation and redeposition of waxes induces surface cracks increasing routes of vapour loss. Epidermal cell activity is supported by a network of primary and secondary vascular bundles, breakdown in tissues subtending the epidermis causes physiological disorders, increasing the risk of bruising in fruit and in particular pits in apple and slip skin in grape and cherries where the regions of the epidermis detach from subtending tissues resulting in the loss of saleable quality.

Access to non-destructive hand held devices that afford greater granularity in defining changes in cell turgor, wax deposition and vascular connectivity during develop will help shape future breeding and selection of fruit and vegetables by providing a better understanding of how epidermal cells respond to changes in the rate of fruit expansion and then shrinkage after harvest.

This proposal aims to generate a hand-held Optical Coherence Tomography and associated software that can penetrate the skin surface ( ~1 mm) and allow for high throughput resolution of images to allow sufficient numbers (100’s) of fruit to be processed at a single sitting.