Soya oligosaccharides

Specifically on soya bean fermentations, reviews on Thua Nao (Chukeatirote, Dajanta, Apichartsrangkoon, 2010), the use of okara (soya milk residue) (O Toole, 1999) and the functionality of soya oligosaccharides (Choct, Dersjant-Li, McLeish, Peisker, 2010) are reconunended. 

The digestibility of soya is limited because of the presence of some anti-nutritional factors such as trypsin inhibitors, lectins and flatulence-causing oligosaccharides, and because of structural barriers (cell walls) that are poorly digestible and that inhibit diffusion of digestive enzymes. 

The defatted toasted soya flour can be upgraded to a concentrate (70 % protein) by removing soluble material by leaching with water, or better still, with aqueous alcohol. This removes the oligosaccharides, sugars with 2-5 hexose units, i.e. sucrose, raffinose, stachyose and verbascose. Of these, the last three are recognised as flatus factors since it has been demonstrated that their metabolism involves intestinal gas production. 

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