There’s no such thing as junk
food. Some foods are just not as nutritious as others.” So says Dr.
Rickey Yada, Professor of Food Science at the University of Guelph,
rising in defence of the popular potato chip.
There’s no such thing as junk food. Some foods are just not as nutritious as others.” So says Dr. Rickey Yada, Professor of Food Science at the University of Guelph, rising in defence of the popular potato chip.
Yada was addressing a group of potato professionals at the 8th Annual Potato Research Field Day held in August at the Elora Research Station in Elora, Ontario, where scientists, potato farmers, and restaurant and food industry representatives gathered to view this year’s potato trial results from 89 varieties currently under scrutiny.
As a food scientist, Dr. Yada often finds himself in the role as a potato chip ambassador, and on this day he had a chance to share some of the words of wisdom that he passes on in answer to many questions he receives on a daily basis, as well as highlighting some of his current research.
Are potato chips ‘junk food’? As far as Dr. Yada is concerned, what makes you feel good leads to a less stressful life, so if eating potato chips can do that, more power to them. Although nutrition is important, eating food is also about aesthetics and the taste-good, feel-good qualities that eating conveys. Chips aren’t all bad – although one does not typically eat potato chips as a source of vitamin C, Yada noted that they do have more vitamin C on a per gram basis than raw potatoes.
When he is asked to speak to school children about their diet, he sees his role as helping them to make informed choices – “give ‘em the facts” – to empower them through knowledge. Chips are okay, but the message he tries to convey is, “it’s all about moderation.”
On the research side, factors such as storage traits are currently the subject of investigation by Dr. Yada and his team – why do some varieties store better than others?
Yada explained that potatoes are thought to be invincible but they can be damaged. He describes them as a living, breathing entity, even after they come out of the ground. If you doubt this, he says, look at the ‘Jack and the Beanstalk’ you end up with when you store them under the sink.
Unfortunately, although it would be ideal to store potatoes at low temperatures to slow their metabolism, putting them in the fridge could result in producing a dark product after processing such as frying. The problem is that consumers don’t want dark brown potato chips.
The phenomenon being studied is called low temperature sweetening, or LTS. What scientists do know is that sugars, and their interaction with protein, are the primary determinant of chip colour, but they don’t know exactly why one variety will respond differently to storage than another.
To confuse the issue more, the same variety of potatoes grown in Leamington won’t have exactly the same qualities as those grown in Elora. “Potatoes, like people, are really unique,” says Dr. Yada.
Part of his research is looking into what makes some varieties more suitable for storage than others. To do this he is working with his research associate Dr. Reena Pinhero, trying to identify “biomarkers” – compounds in potatoes that are related to certain traits such as LTS.
Their research into LTS initially started with one variety, North Dakota 860-2, which showed low temperature resistance that they actually discovered by mistake. Normally, table stock is stored at 10 to 12˚ C but when it was accidentally stored at the seedstock storage temperature of 4˚ C, it was not adversely affected.
“We chipped it and it was the colour we wanted,” said Yada. Now it’s his job to find out why.
By identifying the biomarkers associated with LTS, scientists can then select for this trait. As an added bonus, these biomarkers may also be useful in the future for identifying potatoes as a means of traceability through the food chain, something that is on the consumer demand radar screen.
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