Samena Chaudhry Birmingham

Irradiation could reduce the flatulence caused by eating beans. Scientists at the food science laboratory at the Bhabha Atomic Research Centre, Trombay, India, used standard food irradiation technology and discovered that zapping beans reduces the chemicals which cause flatulence.

The researchers tested mung beans, chickpeas, black eyed beans, and red kidney beans. Some samples were treated with a low intensity gamma ray beam, others with a beam three times as strong. All beans were then soaked in cold water for two days before testing (oligosaccharide concentrations are reduced naturally by soaking.) Soaking plus a low dose of radiation reduced oligosaccharide concentrations in mung beans by 70%. Concentrations in beans treated with a high dose decreased by 80%. In untreated beans soaking reduced concentrations by only 35%. Although black eyed beans and chickpeas also showed a marked oligosaccharide reduction, kidney beans were unaffected by the treatment.

When bacteria in the large intestine break down certain types of carbohydrates--oligosaccharides--they produce sulphurous gases which make wind smell. The average adult produces four to five litres of gas a day.

Jammala Machaiah, who carried out the research with a colleague, explains, "In India, beans are a very popular and important part of the national diet, but some people can't eat a lot of beans because of the flatulence problem. This is unfortunate, as they are a very good source of essential nutrients. Irradiation would make beans less of a problem."

In Europe, food can be irradiated only under licence. The process extends the shelf life of herbs and spices by killing the bacteria that make them rot.