“Because obesity is a growing health problem, especially in many developing countries, we wanted to find food-based solutions,” said team leader Sudhair A James from the College of Chemical Sciences, Colombo, Sri Lanka. “We discovered that increasing rice resistant starch (RS) concentrations was a novel way to approach the problem,” he said.
Scientists used a specific heating and cooking regimen and determined that when using the best variety of rice is processed, the method of cooking might reduce the calories between 50 and 60 percent.
Rice contains starch which can be digestible or indigestible. Unlike digestible types of starch, RS is not broken down in the small intestine, where carbohydrates normally are metabolised into glucose and other simple sugars and absorbed into the bloodstream.
Based on this observation, scientists determined that if they could transform digestible starch into RS, the result is a reduced number of rice calories the body will use.
“After your body converts carbohydrates into glucose, any leftover fuel gets converted into a polysaccharide carbohydrate called glycogen,” James said.
In the study, scientists used 38 types of rice from Sri Lanka and developed a new way of cooking the rice that increased the RS content. The method consists of adding a teaspoon of coconut oil to boiling water. Next, they added a cup of rice, and let it simmer for 40 minutes even though boiling it for 20-25 minutes worked as well. In the final stage, scientists refrigerate the rice for 12 hours. As a result, the procedure increased the RS ten-fold for traditional, non-fortified rice.
Reheating the rice for consumption does not affect the RS levels, James noted.
The study was presented at the National Meeting & Exposition of the American Chemical Society (ACS) in Denver.