PURPOSE: To obtain the titled dextrin and oligosaccharide in the nonreducible syrup with selective fractionation without causing discoloration, by decomposing starch with α-amylase followed by hydrogenation.

CONSTITUTION: Starch is subjected to α-amylase so that the decomposition rate pref. be DE 10W40, to form a saccharized liquid comprising branched dextrin and straight chain oligosaccharide. Thence, the resulting saccharized liquid is hydrogenated into a non-reducible syrup, which is then brought into contact with a gel type filter medium (pref. ion exchange resin with a crosslinking degree of 4W8 and granular size of 40W80 mesh) followed by, pref. through a pseudo-moving bed system, selective fractionation of the objective non-reducible branched dextrin and non-reducible straight chain oligosaccharide in the syrup to obtain the both products.