A process for producing alpha-amylase resistant starch comprises extruding a feed starch at a temperature in the range of about 60-220.degree. C., thereby producing a product alpha-amylase resistant starch. The feed starch can be in the form of an aqueous slurry or paste that has a dry solids concentration of at least about 50% by weight. The process optionally can include the additional step of heating the product starch to a temperature of at least about 90.degree. C. in the presence of moisture, to increase further the alpha-amylase resistance of the product.