The answer lies in microwave heating: it accelerates moisture loss, shortens cooking time and reduces oil absorption.
A new way has recently been discovered to reduce the amount of oil absorbed by fried foods, such as French fries, without compromising the crispy texture we love so much.
The solution announced by a team of researchers at the University of Illinois Urbana-Champaign involves combine microwave heating with frying conventional, according to two recent studies.
Fried foods remain among the most popular, but their high fat content has long been linked to worrying health problems such as obesity and high blood pressure. Producing lower-fat versions of these delicious foods while preserving flavor and texture was a priority for the Illinois team, led by Pawan Singh Takharprofessor of food engineering in the Department of Food Science and Human Nutrition at the North American university.
In studies ( and ), carried out in collaboration with the University of Washington, researchers used a microwave fryer designed to operate at two frequencies: 2.45 gigahertz, similar to that of a household microwave, and 5.8 gigahertz. The potatoes were washed, peeled, cut into strips, blanched, salted and then fried in soybean oil heated to 180 degrees Celsius. During and after cooking, the team monitored temperature, pressure, volume, texture, moisture content and oil absorptionto understand how oil gets into food during frying.
Initially, the potato’s microscopic pores are filled with water, which prevents oil from entering. As the water evaporates, voids and negative pressure conditions are created that favor oil penetration. This is where the microwave heating could make a difference.
Unlike conventional heating, which transmits heat from the outside to the inside, microwaves heat the food more internally, making the water molecules oscillate and promoting greater steam formation. This effect shifts the pressure profile to more positive values, reducing the tendency for oil to enter the food structure, explains .
The results show that the Microwave frying accelerates moisture loss, shortens cooking time and reduces oil absorption. However, used alone, it tends to produce soft foods. Therefore, researchers advocate combining the two methods in the same equipment: conventional heating ensures crispiness, while microwaves help to reduce the fat content.
The team is confident that their approach could be applied on a large scale: they suggest retrofitting continuous industrial fryers with microwave generators.
