Dr Thanatuksorn and his team at Tokyo University of Technology studied how the structure of the batter molecules changes during the frying process. By altering the water content and frying time they were able to suggest the perfect conditions to create batter with the best lasting crispiness, as well as helping to reduce the fat content (Journal of the Science of Food and Agriculture DOI 10.1002/jsfa.3027).
During the deep-frying process a rigid microstructure of pores is formed in the batter, and this microstructure is responsible for the textural properties of the food, as well as determining how much oil is absorbed during the frying. The amount of water in the batter before and after frying is critical. Water evaporates during cooking creating the pores responsible for crispiness, but residual moisture remaining after causes the batter to go soggy.
According to Thanatuksorn's research, larger pores trap less oil during cooking so will reduce the amount of fat in the cooked food. By using a batter with a moisture content of 60% and frying for 5 minutes a highly crisp lower-fat batter is formed. The scientists say the residual moisture should be less than 5%.
Thanatuksorn says this method can be extended to other food types, so next on the menu could be perfect chips.