Nowadays, the majority of prebiotics sold in the market are non-digestible oligosaccharides. Inulin, fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), lactulose and polydex- trose are recognized as the well established prebiotics, whereas isomaltooligosaccharides (IMO), xylooligosaccahrides (XOS), and lactitol are categorized as emerging prebiotics
However, there are few investigations on non-digestible long chain complex carbohy- drates as potential prebiotics. Resistant starch-rich whole grains can be considered as having prebiotic action since they are not absorbed in the small intestine of healthy individuals but are later fermented by gut microflora to produce short chain fatty acids (SCFAs)
Nevertheless, there are still some non-digestible long chain complex carbohydrates that are candidates as potential pre- biotics. Longer chain prebiotics can sometimes be referred as “slowly fermentable” substrates