Researchers have discovered a key mechanism behind the darkening and potential health concerns associated with cold-stored potatoes.
The findings hold promise for the development of potato varieties that could be stored under cold temperatures and lead to healthier and tastier chips and fries.
These snacks have a market worth billions of dollars in the US. In Michigan—the nation’s leading producer of potatoes for chips—the potato industry is valued at $240 million annually.
But farmers can’t grow the crops year-round and snack makers need a constant supply of fresh spuds to meet their demands. Preserving spuds in cold storage ensures chip and fry producers have what they need, but the low temperatures also trigger a process called cold-induced sweetening, or CIS, which converts starches to sugars.
Processing tubers loaded with sugars results in darkened fries and chips. It also generates acrylamide, a carcinogenic compound formed during high-temperature processing, which has been linked to health concerns including an increased cancer risk.
Although there are techniques to reduce the impact of sugars in cold-stored tubers, these add cost and can affect the flavor of the final product. So Jiming Jiang, a professor in the plant biology and horticulture department at Michigan State University, and colleagues have focused on the root of the problem to work toward potatoes that aren’t affected by CIS to begin with.
“We’ve identified the specific gene responsible for CIS and, more importantly, we’ve uncovered the regulatory element that switches it on under cold temperatures,” explains Jiang. “By studying how this gene turns on and off, we open up the possibility of developing potatoes that are naturally resistant to CIS and therefore will not produce toxic compounds.”
Jiang has dedicated his career to solving this puzzle.
As one of the most pressing issues in the potato industry, Jiang started his work to minimize acrylamide in potato chips and fries at the University of Wisconsin-Madison. There, Jiang and his team published a paper in 2010 identifying a key gene responsible for potato CIS. Moving to Michigan State in 2017, Jiang and his team have worked to pinpoint which elements of that gene could be modified to stop the process of cold-induced sweetening.
Jiang’s research team used a combination of gene expression analysis, protein identification, and enhancer mapping to pinpoint the regulatory element controlling the CIS gene.
The potential benefits of this research extend beyond improved snack food quality. Reducing acrylamide formation in potatoes could have implications for other processed starchy foods. Additionally, cold-resistant potatoes could offer greater flexibility in storage and transportation, potentially reducing food waste and costs.
Jiang believes the new CIS-resistant potatoes could be commercially available in the near future.
“This discovery represents a significant advancement in our understanding of potato development and its implications for food quality and health,” says Jiang. “It has the potential to affect every single bag of potato chips around the world.”
The findings appear in the journal The Plant Cell.
Source:Samantha Brichta for Michigan State
