Turning off a gene in potatoes creates potato chips with less carcinogens

While you might not think about the intricacies of cold-storage while enjoying a packet of chips, a new study has brought the darkest chips into the spotlight.

Researchers in the US have created a genetically modified chip that doesn’t darken as easily – if successful this would minimise waste for the spud industry and limit a potential carcinogen from ending up in your snack.

“This discovery represents a significant advance in our understanding of potato development and its implications for food quality and health,” said Michigan State University professor Jiming Jiang.

“It has the potential to affect every single bag of potato chips around the world.”

Potatoes are only harvested once a year, but our obsession for the starchy vegetable lasts all year. So, to keep up with that demand, tuber producers put their potatoes into cold storage.

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This helps protects potatoes from all kinds of diseases and ways it could spoil. However, it also increases the expression of a gene in the potato which turns starches into sugar.

“This process, referred to as ‘cold-induced sweetening’ (CIS), is a major postharvest problem for the potato industry,” the researchers write in their new paper.

When the chips are deep fried, this extra sugar increases the Maillard reaction, which causes darker chips and produces more acrylamide – the char which is a potential carcinogen.  

There’s been some work looking into this in the past, and researchers discovered back in the early 2000s that it was a gene called VInv that was to blame for CIS. But current solutions to this problem add cost and reduce flavour.

Instead, the team looked at the section of DNA which controls the gene itself.

“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,” explained 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.”

Vinv fried potatoes 1
Credit: Bhaskar, P.B., et al. Plant Physiology, 2010, 154 (2), 939–948

Using CRISPR/Cas-9 gene editing, the team created potatoes that had that regulatory switch turned off. This produced potatoes that had less CIS and didn’t brown the same way.

However, we cannot confirm if the researchers tried these creations, and more research will need to be done to confirm if this is the next big chip.  The research has been published in The Plant Cell.

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