An improved method for hydrolysis of a grain product results in an increase soluble fiber content without producing undesirable levels of by-products associated protein hydrolysis. The method comprises mixing at high shear a mixture with a grain product having dietary fiber, a base and water at a pH from about 10 to about 13. A homogenous mixture is formed that hydrolyzes following heating with respect to the insoluble fiber. As described herein, a grain product can comprise at least about 30% dietary fiber comprising polysaccharides with arabinoxylan linkages, having at least about 8% soluble fiber, a ratio of soluble fiber to insoluble fiber of at least about 0.1 and no more than about 500 ppm total lysinoalanine. Similarly, some food compositions can comprise at least about 15% soluble fiber with polysaccharides having arabinoxylan linkages, from about 35% to about 65% water, a pH from about 10 to about 13.