What's in potato peels?

What sort of bounty could possibly lie in piles of discarded potato peelings?

“We have been interested in by-products for quite a while now,” says Dr Nigel Brunton, a senior research officer with Teagasc who works with phytochemicals derived from plants. “They are mostly defence compounds the plants produce themselves that may have a beneficial effect for human health.”

Brunton and colleagues are currently looking for valuable chemicals in potato peels, which crisp manufacturers Largo Foods are only too happy to donate for the research.

The company produces around 30 to 40 tonnes of wet peel each week, and has to pay for its disposal, says Brunton. “So if we can do anything useful at all with the waste, that’s a good thing.”

Funded under the Department of Agriculture and Food’s Firm scheme, the scientists at Ashtown are starting to examine the peels for glycoalkaloid compounds, which can be toxic at high levels but have already proven their mettle when used as a topical treatment for skin cancer.

The project, which involves collaborators at University College Cork, will isolate glycoalkaloids from the potato waste and hopefully find some novel compounds in the process, explains Brunton.

Glycoalkaloids could also help farmers to ward off nematode (roundworm) pests, he says, noting that collaborator Peter Jones at UCC is working on this. “Nematodes are present as eggs in the soil and the glycoalkaloids basically cause the nematodes to hatch out,” explains Brunton. “So at a time when there are no potatoes growing there you apply the potato peel waste or the glycoalkaloid to the soil, causing the nematodes to hatch out, and they have no food source so they die.”