Which of the following will not be sweet in taste?

Glycogen

The correct answer is option 2. Glycogen.

The sweetness of a carbohydrate is influenced by its chemical structure and how it interacts with taste receptors on the tongue. Let us break down each option:

1. Maltose: Maltose is a disaccharide composed of two glucose molecules linked together. Glucose is a monosaccharide known for its moderate sweetness. Therefore, maltose is moderately sweet in taste due to the presence of glucose.

2. Glycogen: Glycogen is a polysaccharide composed of long chains of glucose molecules linked together. Unlike monosaccharides and disaccharides, glycogen is not sweet in taste. This is because its complex structure and large size prevent it from interacting effectively with the taste receptors on the tongue that perceive sweetness.

3. Lactose: Lactose is a disaccharide composed of one glucose molecule and one galactose molecule linked together. While lactose is a sugar, it is not as sweet as other sugars like fructose or sucrose. In fact, some individuals perceive lactose as having a slightly "bitter" taste, especially those who are lactose intolerant and cannot properly digest lactose.

4. Fructose: Fructose is a monosaccharide commonly found in fruits and honey. It is the sweetest of all natural sugars and is responsible for the sweet taste of fruits and many sweetened products. Fructose interacts strongly with sweetness receptors on the tongue, giving it its characteristic sweet taste.

In summary, while maltose, lactose, and fructose are sweet-tasting carbohydrates, glycogen, being a polysaccharide, does not exhibit sweetness due to its complex structure and large size. Therefore, among the options provided, glycogen is not sweet in taste.