Tofu Whey Permeate Is an Efficient Source To Enzymatically Produce Prebiotic Fructooligosaccharides and Novel Fructosylated α-Galactosides

This work addresses a novel and efficient bioconversion method for the utilization of tofu whey permeate (TWP), an important byproduct from the soybean industry, as a precursor of high value-added ingredients such as prebiotic fructooligosaccharides and novel fructosylated α-galactosides. This process is based on the high capacity of the commercial enzyme preparation Pectinex Ultra SP-L to transfructosylate the main carbohydrates present in TWP as sucrose, raffinose, and stachyose to produce up to a maximum of 164.2 g L(-1) (equivalent to 57% with respect to initial sucrose, raffinose, and stachyose contents in TWP) of fructooligosaccharides and fructosylated α-galactosides in a balanced proportion. Raffinose- and stachyose-derived oligosaccharides were formed by elongation from the nonreducing terminal fructose residue up to three fructosyl groups bound by β-(2→1) linkages. These results could provide new findings on the valorization and upgrading of the management of TWP and an alternative use of raw material for the production of FOS and derivatives.