2.1D: Polysaccharides

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Within complex carbohydrates, there are oligosaccharides and polysaccharides. Oligosaccharides (oligo means few) are composed of 3-10 sugar units and polysaccharides contain greater than 10 sugar units.

Figure 2.141.png

Figure 2.141: Overview of carbohydrates

Raffinose and stachyose are the most common oligosaccharides. They are found in legumes, onions, broccoli, cabbage, and whole wheat¹. The link below shows the raffinose and stachyose content of some plant foods. The structures of the two oligosaccharides are shown below.

Figure 2.142.png Figure 2.143.png

Figure 2.142: Structures of raffinose (left) and stachyose (right).

Our digestive system lacks the enzymes necessary to digest these alpha 1-6 glycosidic bonds found in oligosaccharides. As a result, the oligosaccharides are not digested and reach the colon where they are fermented by the bacteria there. Gas is produced as a byproduct of this bacteria fermentation that can lead to flatulence. To combat this problem, Beano® is a popular product that contains an enzyme (alpha-galactosidase) to break down oligosaccharides, thereby preventing them from being used to produce gas.

References & Links

Byrd-Bredbenner C, Moe G, Beshgetoor D, Berning J. (2009) Wardlaw's perspectives in nutrition. New York, NY: McGraw-Hill.
en.Wikipedia.org/wiki/File:Raffinose.png
en.Wikipedia.org/wiki/File:Stachyose.png

Contributors and Attributions

Brian Lindshield (Kansas State University). Content originates from the Human Nutrition (FNDH 400) Flexbook. goo.gl/vOAnR.