April 25, 2006
Study Shows Secret to Gas-Free Beans
WASHINGTON -- Two strains of bacteria are the key to making beans flatulence-free, Venezuelan researchers reported on Tuesday.
They identified two bacteria, Lactobacillus casei and Lactobacillus plantarum, which can be added to beans so they cause minimal distress to those who eat them, and to those around the bean-lovers, Marisela Granito of Simon Bolivar University in Caracas, Venezuela and colleagues reported.Flatulence is gas released by bacteria that live in the large intestine when they break down food. Fermenting makes food more digestible earlier on.
Writing in the Journal of the Science of Food and Agriculture, Granito and colleagues found that adding these two gut bacteria to beans before cooking them made them even less likely to cause flatulence.
They tested black beans, known scientifically as Phaseolus vulgaris.
"Legumes, and particularly Phaseolus vulgaris, are an important source of nutrients, especially in developing countries," Granito's team wrote in the report.
"In spite of being part of the staple diets of these populations, their consumption is limited by the flatulence they produce."
Smart cooks know they can ferment beans, and make them less gas-inducing, by cooking them in the liquor from a previous batch. But Granito's team wanted to find out just which bacteria were responsible for this.
When the researchers fermented black beans with the two bacteria, they found it decreased the soluble fiber content by more than 60 percent and lowered levels of raffinose, a compound known to cause gas, by 88 percent.
They fed the beans to rats and then analyzed the rats' droppings to ensure that the beans were digested and kept their nutritional value.
When pre-soaked in the L. casei, the beans stayed nutritious and produced few gas-causing compounds, they reported.
"Therefore, the lactic acid bacteria involved in the bean fermentation, which include L. casei as a probiotic, could be used as functional starter cultures in the food industry," the researchers wrote.
"Likewise, the cooking applied after induced fermentation produced an additional diminution of the compounds related to flatulence."