Corn bran, as one of the high‐fructose corn syrup industries’ by‐products, is a rich source of functional fibers. The major fraction of corn bran is insoluble arabinoxylan having lower functional properties than the minor soluble function. Therefore, the main aim of this research was to increase the soluble fiber content of corn bran and use it for functional cake production. In this regard, milled corn bran with three different sizes was exposed to one factor enzymatic treatment to select the best sieving size (the criterion for selecting the best product in each stage of assay was production of the highest amount of soluble fiber). Then, milled corn bran with the best particle size was exposed to nine different enzymatic treatments to select the best enzymatic treatment condition. Additionally, the extruder feed (corn bran) moisture was adjusted to three levels to select the best level of feed moisture content and use it for performing nine different extruding experiments. Concerning integrated extrusion‐enzymatic treatment, nine different extruding pretreatments were conducted on corn bran through selecting the optimum moisture level of extruding. Afterward, the product was milled and sieved to the optimum size for enzymatic treatment, and the nine pretreatments were combined with nine different enzymatic treatments. The product containing the highest soluble fiber was selected and used at various levels for functional cake production. Finally, some organoleptic and physicochemical properties (springiness, gumminess, hardness, cohesiveness, Bostwick number, density) of the produced product were analyzed.