What exactly makes fried foods so impossible to ignore?
Pawan Takhar, a researcher and “food scientist” at the University of Illinois decided to use an interesting new method to find out the answer: an X-ray machine.
As reported by UPI, , Takhar and his team of researchers conducted a study on fried foods using an X-ray micro-computed tomography (micro-CT) machine to create 3-D images of fried potato disks that had been deep-fried for varying lengths of time.
Because X-ray machines can accurately scan and map items that are incredibly small — sometimes as small as .5 mm in length — Takhar found that the resulting 3-D images would be able to accurately depict the microstructures of the food as more oil saturated it.
Researchers used russet potatoes cut into disks that measured 45 mm in diameter and 1.5 mm thick. The disks were fried at 190 degrees Celsius for 20, 40, 60, or 80 seconds and then freeze-dried before being scanned and examined to understand how the oil was distributed.
When food is deep-fried, Phys.org explains, the food is immersed in hot oil and water in the food evaporates very quickly. This results in steam pressure, and the pressure builds up so much that it affects the microstructure and the porosity of the food. As the food becomes more porous, “pathways” of pores open up and allow more oil to seep in.
Using the X-rayed images, the researchers were able to see how different porous pathways formed when the same type of food was heated for different lengths of time. The pathways are very complex at first and make it difficult for oil to penetrate past the surface. As the food heats up, the pathways become looser and the oil is able to soak farther into the food.
This is exactly what makes fried foods — especially french fries — so tempting, Takhar says. The foods are cooked at a very high temperature for a very short length of time and this results in a crispy exterior and softer interior.
Takhar has been studying frying for about 10 years now and he still says that researchers probably “only understand about 10 percent of what is taking place during frying.” Hopefully, he says, this recent research will help food scientists figure out how to make healthier foods just as tempting as fried foods — and without any frying involved.
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