A prebiotic is a substrate selectively utilised by host microorganisms, conferring a health benefit. Inulin qualifies because its β(2→1) bonds resist human digestive enzymes, delivering fermentable substrate to the colon.
Inulin enters as part of a food, beverage or supplement matrix, dissolved, dispersed or bound.
Acidic conditions may partially hydrolyse a small share of the chain, but the fructan structure largely persists.
No human enzyme cleaves β(2→1) bonds. Inulin is not absorbed here, which is also why it contributes little available energy.
Resident microbiota, including Bifidobacterium and Lactobacillus populations, utilise inulin as a substrate. Shorter chains are generally fermented faster and more proximally. Longer chains more slowly and more distally.
Fermentation yields short-chain fatty acids (acetate, propionate, butyrate) and gases. SCFAs are the main conceptual output shown in the ecosystem above.
Inulin belongs to the fructan family: linear chains of fructose units joined by β(2→1) glycosidic bonds, typically ending in a glucose unit (GFn). Human digestive enzymes hydrolyse α-bonds, not β(2→1), so inulin passes the small intestine largely intact.
Degree of polymerization (DP) is the number of monomer units in a chain. Native inulin from any source is a distribution of chain lengths, not a single molecule. Botanical source, cultivar, harvest timing and processing shift that distribution. Purification and fractionation can narrow it into a specific grade.
The directions below are widely reported trends for inulin-type fructans. Magnitudes depend on grade, concentration, pH, temperature and the food matrix, evaluate in your own system.
Exact DP distribution for the supplied grade is provided on the current technical data sheet.