What Are Oligosaccharides and Starches?

Monosaccharides not only serve as building blocks for disaccharides but also for some larger forms of carbohydrates as well. The most recognizable larger carbohydrate is starch. Starch is found in varying degrees in plants and their products (for example, legumes, vegetables, fruits, and grains). It consists of large, straight and branching chains of the

monosaccharide glucose (Figure 4.1). Some shorter, branching chains of glucose can be found as well, and food manufacturers will also use these in the production of foods. The short, branching chains used by food manufacturers are often called maltodextrins and is typically derived from the partial digestion of corn starch.
 

In the human diet, we can also find a small amount of carbohydrates, called oligosaccharides, constructed from just a few monosaccharides (three to ten) linked together. Since these are found in relatively small amounts, they are not as essential to discuss. However, a few of these carbohydrates (for example, raffinose and stachyose) will require mention later on, not only for their nutritional value but for their effects within the digestive tract.
 

Plants make starch to store energy kind of like mammals store fat. Plant fibers, on the other hand, are not necessarily stored energy but serve more structural roles for plants. Like starch, fiber is also composed of straight and branching chains of monosaccharides, but their monosaccharides building block are not limited only to glucose. Fibers are discussed later in this chapter.