Beans, Beans
Beans, beans, they’re good for your heart, the more you eat the more you…uh, well, you know how the rest goes. What is is about eating beans in particular that has such memorable after effects?
Bite-Sized Science
Beans and other vegetables such as cabbage, broccoli, and Brussels sprouts contain a carbohydrate (carb) called raffinose. Our bodies can’t digest raffinose, but the bacteria in our gastrointestinal system can. These bacteria produce gas when they eat the raffinose, which we then expel to the delight of those around us. To decrease the amount of raffinose consumed (and gas produced) when eating beans, you can soak beans in water before cooking.
A Closer Look
Carbohydrates are one of the four macromolecules that make up our bodies. Carbohydrates are also called “carbs,” “sugars,” and “saccharides.” Carbohydrates are made of individual subunits or monomers that connect together like pop beads to form more complicated structures. For example, glucose is made of one sugar unit. Starch is a carbohydrate used for storage in plants is made of thousands of sugar units. Raffinose is an oligosaccharide, meaning it has a few sugar units.
Breaking down complicated carbohydrates requires specialized help called enzymes. Although we have the enzymes for breaking down carbohydrates such as glycogen (which supplies energy when you’re working out) we do not have the enzymes to break down cellulose (which as part of our diets is called fiber) or raffinose. Carbohydrates will dissolve in water, which is why soaking beans prior to eating them and then discarding the water is an effective strategy for decreasing gas after eating beans.
Suggestions for Teaching
Have students research other carbohydrates in our diet. Which ones can we digest?
Have students research other raffinose containing foods. See if they can figure out how Beano works.
Have students research other macromolecules in our diet (protein, lipids (fats), nucleic acids).