Galactooligosaccharide (GOS) is not only a water-soluble dietary fiber but also a natural active substance. Its thermal energy value is relatively low, allowing it to be well absorbed and utilized by the intestinal tract without causing obesity. Furthermore, it is resistant to oral flora, helping to avoid dental caries while enhancing the body's natural resistance.

In nature, trace amounts of GOS exist in animal milk, whereas human breast milk contains a significant amount. The establishment of bifidobacteria flora in infants largely depends on these GOS components. Its molecular structure typically consists of 1-7 galactose groups connected to galactose or glucose molecules.