Combining traditional frying with microwave heating may produce French fries that are less greasy without ruining their taste, according to scientists. Researchers claim their technique could reduce the amount of oil absorbed during frying while still producing crispy chips.
Study leader Professor Pawan Singh Takhar, an expert in food engineering at the University of Illinois Urbana-Champaign, US, said: “Consumers want healthy foods, but at the time of purchase, their cravings often take over. High oil content adds flavour, but it also contains a lot of energy and calories.
“My research team studies frying with the aim of obtaining lower fat content without significant differences in taste and texture.”
A key challenge when frying is preventing oil from entering food, Prof Takhar explained.
Early in the process, the potato’s pores are filled with water, leaving no space for oil. That water evaporates while cooking, creating empty spaces that allow oil to be drawn in through negative pressure.
The team initially worked with researchers at Washington State University to use a specially designed microwave fryer.
Potatoes were rinsed, peeled, cut into strips, blanched, and salted, then fried in soybean oil heated to 180C.
Prof Takhar said: “When we heat something in a conventional oven, the heat moves from outside to inside, but a microwave oven heats from the inside out, because the microwaves penetrate everywhere in the material.
“The microwaves oscillate water molecules, causing more vapour formation and thus shifting the pressure profile towards the positive side. The higher pressure in microwaves helps reduce oil penetration.”
This method of microwave frying led to quicker moisture loss and lower oil update, but did not produce the desired texture.
Prof Takhar added: “If you just use microwave frying, you get soggy food. To obtain a crispy texture and taste, you need conventional heating.
“Therefore, we propose combining the two approaches in the same unit. Conventional heating maintains the crispiness, while microwave heating lowers the oil intake.”
The team suggested that industrial fryers could be upgraded with low-cost microwave generators to use this combined method for large-scale food production.
Their findings were published in the Journal of Food Science and Current Research in Food Science.
Dining and Cooking