Types of Raffinose Sugar

Beans contain high levels of raffinose.

The carbohydrate raffinose belongs to a larger family of sugars and starches. Raffinose contains three mono-saccharides parts, which makes it an oligosaccharide, a term reserved for all carbohydrates with three or more mono-saccharides. Known scientifically as substances like glucose and fructose, mono-saccharides commonly get called simple sugars. Raffinose, because it contains three mono-saccharides units, breaks down into simple sugars under the right conditions.

Sources of Raffinose

Found in a wide variety of carbohydrate-rich vegetables, raffinose provides the majority of the energy-giving substance in beans, peas and lentils. It's also found in some cereal grains such as wheat and rye. Green leafy vegetables like cabbage, asparagus, artichokes, Brussels sprouts and broccoli contain raffinose, as do onions and mushrooms in smaller amounts. Even non-edible plants such as yew manufacture raffinose in their leaves and stem.

Raffinose and Yeast

Yeast uses the energy from carbohydrates to reproduce, leaving behind simple sugars and carbon dioxide. Grains contain high levels of raffinose. The yeast in a bread recipe breaks down the raffinose in the wheat, leaving behind carbon dioxide gasses that cause the bread to rise and enough sugar to give the loaf a brown crust or the ability to toast to a golden brown. The more yeast in a loaf of bread, the higher the concentration of sugar. Thanks to raffinose, light, fluffy bread tastes sweeter and toasts better than heavier, denser loaves.

The Raffinose Taste Test

Closely related to sugar, raffinose tastes sweet but not as sweet as sugar. Pure raffinose tastes about 30 percent as sweet as mono-saccharides or simple sugars. This means that raffinose produces a sweet taste, but it takes more raffinose to get the same flavor. A recipe using raffinose requires roughly three and a half times the amount of raffinose to equal the flavor of sugar.

Raffinose and Digestion

Considered an indigestible carbohydrate, raffinose goes through the digestive system unused. This helps anyone counting calories or carbohydrates. High levels of raffinose impart the flavor of sugar without affecting insulin production or calorie count. Many low-carbohydrate foods contain raffinose. However, yeast breaks down raffinose and the human digestive tract naturally contains yeast, especially in the large intestine. This creates carbon dioxide bubbles in the large intestine, leading to bloating, gas pain and flatulence.

References

• Agriculture and Consumer Protection Agency: Dietary Carbohydrate Composition
• National Institutes of Health: A Simple Technique for Detecting Melibiose Fermenting Yeasts
• Consumer Reports Health.org: Intestinal Gas -- A Right of Passage