Rice is the staple food of people in China, Japan, India and parts of Africa. But it is increasingly posing problems of obesity among its consumers given that it is rich in fat-forming carbohydrates REUTERS

A new way of cooking rice has been shown to reduce its calories by as much as 50 percent and tackle obesity problems for rice eaters.

By cooking rice with a few spoons of coconut oil and then freezing the cooked rice, a student at the College of Chemical Sciences, Colombo, was able to achieve a 10 to 12 percent reduction in calories.

He expects to reduce the calories further by as much as 50 to 60 percent for better rice varieties.

Increasing resistant starch (RS) concentrations in rice was the novel approach adopted to the problem of calories.

"What we did is cook the rice as you normally do, but when the water is boiling, before adding the raw rice, we added coconut oil—about 3 percent of the weight of the rice you're going to cook," said Sudhair James, who presented his work at National Meeting & Exposition of the American Chemical Society (ACS). "After it was ready, we let it cool in the refrigerator for about 12 hours. That's it."

Rice has about 240 calories per cup. White rice is high in starch, both digestible and non-digestible types.

The digestible starches are quickly digested and turn into glucose, and then later glycogen. Excess glycogen ends up adding to the size of our guts if we don't expend enough energy to burn it off.

The resistant starches take a long time for the body to process, and are not converted into glucose or glycogen because we lack the ability to digest them and add up more calories.

So the idea was to transform digestible starch into RS and lower the number of usable calories of the rice.

James and his professor tested eight different recipes on 38 different kinds of rice found in Sri Lanka. By adding a lipid (coconut oil in this case, because it's widely used in Sri Lanka) ahead of cooking the rice, and then cooling the rice immediately after it was done, reduced its composition.

The oil enters the starch granules during cooking, changing its architecture so that it becomes resistant to the action of digestive enzymes and does not contribute to the calorie offering.

Chilling the rice then helps retain the conversion of starches and is not reversed when heating up the rice again.

"The cooling is essential because amylose, the soluble part of the starch, leaves the granules during gelatinization," James explained. "Cooling for 12 hours will lead to formation of hydrogen bonds between the amylose molecules outside the rice grains which also turns it into a resistant starch."

Benefits of RS

Reducing the amount of calories in a cup of rice by even as little as 10 percent could have an enormous impact for future generations.

Resistant starch that never enters the bloodstream has for some time been the hot nutrition trend.

Produced when food is cooked and cooled, resistant starch is a form of dietary fiber naturally found in many carbohydrate-rich foods such as potatoes, grains, and beans, especially when these foods are cooled.

Besides reducing hunger by filling up the stomach, resistant starch is believed to have many benefits.

The starch is fermented by certain bacteria in the gut and is well tolerated in healthy people. But in people with GI issues an excess of resistant starch can lead to gas formation and digestive illnesses.