Which oligosaccharide is mainly found in milk?

Galactooligosaccharides (GOS) are the oligosaccharides primarily found in milk. They are a type of carbohydrate made up of galactose units and are especially abundant in human breast milk. GOS serves important roles in nutrition and gut health, acting as prebiotics that support the growth of beneficial bacteria in the digestive system. This ability to promote healthy gut flora makes them particularly important for infants but also beneficial throughout life.

In contrast, the other listed options do not relate to milk in the same way. Fructooligosaccharides (FOS) are primarily found in plants like onions and garlic, and they are not the primary oligosaccharides in milk. Starch is a polysaccharide commonly found in grains and tubers, serving as a major energy source, but it is not typically associated with dairy. Chitin is a structural polysaccharide found in the exoskeletons of insects and crustaceans, and it has no presence in milk. Therefore, GOS is specifically recognized for its significant association with milk, differentiating it from the other types of carbohydrates mentioned.