Better cold-storage performance could reduce potato waste, extend Ontario supply and create new opportunities for growers.
Keeping Ontario-grown potatoes suitable for potato chip production throughout the winter could become easier thanks to research underway at the University of Guelph.
Researchers are investigating how different potato varieties respond to cold storage, with the goal of identifying potatoes that can remain in storage longer without sacrificing the colour, flavour and processing characteristics required by chip manufacturers.
The work could have important implications for Ontario growers. Better storage performance could reduce potato losses, extend the period when locally grown potatoes are available to processors and potentially reduce the need to bring potatoes into Ontario from other provinces or the United States.
More than half of Ontario's potato crop is used to make potato chips, according to the University of Guelph.
Potatoes destined for chip production are harvested from July through October. Some move directly into processing, while the remainder must be stored to maintain supplies through the winter.
That's where the challenge begins.
The cold storage issue
Cold storage helps suppress sprouting and preserve potatoes, but low temperatures can also trigger a physiological process known as cold-induced sweetening.
During this process, starch in the potato breaks down and reducing sugars accumulate. When potatoes containing higher sugar levels are fried, the result can be chips that are darker and may develop an undesirable bitter flavour.
University of Guelph researchers say cold-induced sweetening can affect as much as 20 per cent of the potato supply, contributing to product rejection, lost revenue, food waste and additional disposal costs.
The university's related research indicates that approximately 15 to 20 per cent of tubers can be rejected by processors because of cold-induced sweetening.
The problem is particularly significant for processing potatoes because manufacturers require consistency in characteristics such as colour and flavour.
Testing potatoes at different temperatures
The research is led by Dr. Katerina Jordan, a professor in the University of Guelph's Department of Plant Agriculture and director of the Guelph Turfgrass Institute.
Working with technician Vanessa Currie at the Ontario Crops Research Centre - Elora and industry partner WD Potato, researchers are storing different potato varieties at various temperatures to identify which varieties are better able to tolerate cold conditions.
They are also investigating new cooling and storage approaches that could be used with emerging potato varieties.
"Storage is an art and a science unto itself," Currie said. "A potato is a living plant, so it breathes, it respires, it has a physiology to it."
The work builds on more than 70 years of potato research at the University of Guelph.
WD Potato is contributing cold storage capabilities as well as sucrose and dextrose analysis to the project.
"Research like this helps bridge the gap between new potato varieties and the practical realities of commercial storage and processing," said Patrick Dol, sustainability, quality and food safety manager with WD Potato.
"Understanding how they respond to different storage temperatures can give growers and the industry more options to maintain high chip quality throughout the storage season."
University of Guelph researcher Dr. Ian Tetlow's laboratory is also analyzing invertase, an enzyme involved in breaking sucrose down into glucose and fructose.
Related University of Guelph research is investigating the biological mechanisms responsible for cold-induced sweetening and identifying potato breeding lines that could have improved cold-storage and processing characteristics.
What could it mean for Ontario potato growers?
Successfully identifying varieties that retain their processing quality during longer periods of cold storage could have benefits throughout the potato supply chain.
For farmers, reducing the number of potatoes rejected because of cold-induced sweetening could mean more of the harvested crop ultimately reaches the processor.
Improved storage performance could also lengthen the window during which Ontario potatoes can supply chip manufacturers. That could help processors maintain a more consistent domestic supply and potentially reduce the need to source potatoes from outside the province during parts of the year.
Jordan believes the research could eventually create opportunities beyond replacing imports.
"Ideally, this could lead to producing more potatoes for Canada to export as well," she said. "We would love to see Ontario expand the types of potatoes grown here."
Those outcomes are longer-term possibilities rather than guaranteed results. The immediate research objective is determining which potato varieties and storage conditions offer the best combination of storage life and processing quality.
The Ontario Potato Board is among the organizations providing financial support for the research.
For Jordan, collaboration among researchers, growers and the potato industry is critical to moving potential new varieties from research plots into commercial production and processing.
"These partnerships are mutually beneficial," she said. "Our industry partners are supportive of U of G and our research both in theory and financially. That support is integral and enabled us to expand our research programs and share knowledge."
If the research succeeds, a better-storing potato could ultimately mean less waste for growers and processors, more Ontario potatoes available throughout the year and a more resilient domestic supply chain.