A batter with a moisture content of 60 per cent and frying for 5 minutes results in a highly crisp lower-fat batter with a residual moisture content below 5 per cent, according to Pariya Thanatuksorn and his research team at Tokyo University of Technology.
The research team developed the parameters by studying how the micro structure of the batter molecules changes during the frying process.
The research is another example of how the study of microstructures and even smaller is resulting in a better understanding of how foods behave under processing conditions.
By altering the water content and frying time they were able to come up with what they claim are the "perfect conditions" to create batter with the best lasting crispiness, as well as helping to reduce the fat content.
During the deep-frying process a rigid microstructure of pores is formed in the batter.
The microstructure is responsible for the textural properties of the food, as well as determining how much oil is absorbed during the frying, Thanatuksorn stated in the resulting research paper.
"The amount of water in the batter before and after frying is critical," he stated.
"Water evaporates during cooking creating the pores responsible for crispiness, but residual moisture remaining after causes the batter to go soggy."
The scientists studied wheat flour batter containing an initial moisture content.
These were fried in oil at 150 ?
C for 1 to 7min.
They then evaluated the thermal properties of wheat flour, structure alteration and the textural properties of the fried samples.
Thanatuksorn's research found that larger pores trap less oil during cooking so will reduce the amount of fat in the cooked food.
Thanatuksorn says the method can be extended to other food types, such as chips.
"The results revealed that physicochemical changes during frying influence the alteration of microstructure and quality of fried food, and the state diagram could be applied to explain the formation of microstructure during the frying process and used as a decision-making tool to choose the proper conditions to provide desirable qualities in fried food," the scientists concluded.
A report on the research is published in the current issue of the Journal of the Science of Food and Agriculture (JSFA), published by the Society of Chemical Industry (www.chemind.org).