Parboiling husked rice reduces arsenic content

Arsenic contamination in rice poses a serious health risk in many parts of the world. But an international study has shown that husking rice before parboiling reduces arsenic content, potentially lowering the risk of cancer.

Rice terrace. Photo: Sebastian Pena Lambarri/Unsplash

Parboiling rice in-the-husk is the traditional method by which rough rice is soaked in water and then partially cooked to nutritionally improve it and make it easier to process or store.

About half of the 700 million tonnes of rice harvested annually across the world is subjected to parboiling. However, according to a study, the traditional method of parboiling does not remove inorganic arsenic which naturally occurs in groundwater and contaminates the husk.

Parboiling husked whole grain, on the other hand, not only reduces arsenic by 25 per cent, but also increases its calcium content significantly, according to the researchers from Bangladesh and Northern Ireland.

Arsenic is found in two forms: inorganic arsenic and organic arsenic, in which the arsenic atoms remain attached to carbon atoms. The aim was to remove inorganic arsenic because it is much more toxic than organic arsenic.

Arsenic causes cancers of the skin, urinary bladder, kidneys and lungs. Besides drinking water, rice is another route to arsenic exposure in countries such as Bangladesh, China, India and Vietnam, where rice is a staple. Rice readily takes up arsenic from soil and groundwater.

This is especially a problem in Bangladesh, where it is estimated that groundwater pumped from shallow aquifers for irrigation adds one million kilograms of arsenic per year to arable soil. Was set a maximum limit of 0.2 milligrams of arsenic per kilogram of polished rice.

Husked whole grain parboiling lets inorganic arsenic escape, the researchers explained. On the other hand, when parboiling unhusked rice, the high levels of arsenic in the husk can get transferred to the grain during the parboiling process.

The scientists, tested the efficiency of the modified parboiling process at 13 locations across Bangladesh and found that it removed 25 per cent of arsenic in whole grain rice across all sites. However, they admitted the process has the drawback that it can lead to significant loss of nutrients like potassium, molybdenum (an essential mineral) and vitamins.

Parboiling whole grain fortifies polished rice grain with calcium by 213 per cent. This is thought to be due to migration of calcium from the outer layer of rice to inner layers during parboiling.

Parboiling of both whole grain and rough rice also enhanced copper, iron and phosphorus, while potassium content decreased, the study found. (SciDev.Net)

YOU MAY ALSO LIKE

International Research Team Finds Correlation Between Genetics and Obesity Is Modified by Diet

A correlation between obesity and genetics has been found to be modified by diet. A research group led by a U.S. Department of Agriculture scientist found that a specific gene—APOA2—can result in a higher body mass index.

Grey Hair Linked with Increased Heart Disease Risk in Men

Grey hair has been linked with an increased risk of heart disease in men.

New Experimental Drug Reverses Hair Loss, Skin Damage

Investigators successfully reversed hair loss, hair whitening and skin inflammation linked using an experimental compound.

Embracing Darker Moods Makes You Feel Better

Pressure to feel upbeat can make you feel downbeat, while embracing your darker moods can actually make you feel better in the long run.

Catalog of Known Near-Earth Asteroids Tops 15,000

The number of discovered near-Earth asteroids (NEAs) now tops 15,000, with an average of 30 new discoveries added each week. This milestone marks a 50 percent increase in the number of known NEAs since 2013, when discoveries reached 10,000 in August of that year.

Anxiety molecules affect male and female mice differently

Researchers found that neurons activated by the “social hormone” oxytocin lessen anxiety in male mice, but not females.