Food grade arabinoxylan product from corn fiber

A method of isolating a food grade arabinoxylan product from corn fiber, wherein the method comprises in sequential order the steps of a) mixing a corn fiber with an aqueous medium to form an aqueous mixture of corn fiber, b) measuring the pH of the aqueous mixture of corn fiber, c) determining whether the measured pH of the aqueous mixture of corn fiber corresponds to a preselected initial pH value, wherein the preselected initial pH value of the aqueous mixture of corn fiber is from 4 to 6, d) if the measured pH does not correspond to the preselected initial pH value, adding an amount of acid or base to the aqueous mixture of corn fiber effective to bring the measured pH into correspondence with the preselected initial pH value, wherein the amount of acid or base is not more than 0.1% by weight based on the weight of the aqueous mixture of corn fiber, e) heating the aqueous mixture of corn fiber for a time and at a temperature effective to extract arabinoxylan oligosaccharide into the aqueous medium from the corn fiber such that at least 80% of the ferulic acid extracted into the aqueous medium is covalently bonded to the arabinoxylan oligosaccharide, and f) separating the aqueous medium containing extracted arabinoxylan oligosaccharide from the corn fiber.