Are FOS and inulin the same thing? No, They are Different.
Different raw materials:
Fructooligosaccharides are sourced from "Sucrose", it is synthesized from high-concentration sucrose water and enzymatically synthesized by fucosyltransferase.
Inulin (FOS) derived from chicory uses natural inulin as raw material, which is enzymatically hydrolyzed by inulinase, and the long-chain is cut into short chains
Different Degree of Polymerization:
Both Inulin and fructooligosaccharides are polysaccharides, that is, multiple fructose molecules are aggregated together, and how many molecules are aggregated together, this quantity is called "Degree of Polymerization or DP". The degree of polymerization of fructooligosaccharides is between 2 and 10, and the degree of polymerization of natural inulin is between 2 and 4.
Ferment Speed Difference:
Natural inulin (mixture of oligofructose 30% and polyfructose 60%) ferment slow and gentle in the colon, but has a more comprehensive range of effects. fructooligosaccharides (Sucrose source) are more quickly fermented in the body.