a process of preparing a starch hydrolysate from wheat , barley or rye comprising the steps of contacting kernels of wheat , barley or rye with an aqueous solution to hydrate and soften the kernels , gently wet - milling the hydrated and softened kernels , separating fibres and pentosans attached thereto as well as germs and gluten from the wet - milled product to form a starch - containing slurry essentially free of insoluble pentosans , carefully washing the fraction to form a refined , starch - containing product , hydrolysing the refined product to form a starch hydrolysate and finally refining the hydrolysate .