A processing method is disclosed that provides malt root of wheat, barley, oats and rye including lots of functional ingredients such as free amino acids or dietary fibers. In more detail, the processing methods provide food or food products, medical products and cosmetic products having high functionality, in which products are provided by processing malt root or extracting functional ingredients from malt root, then using the processed malt or the extracted products as a part of manufacturing materials of food or food products, medical products and cosmetic products. Functional ingredients such as free amino acids like GABA or dietary fibers like .beta.-glucan can be increased by controlling the germination time appropriately, drying or roast-dry temperature appropriately, and both of time of germination and drying or roast-dry temperatures appropriately during soaking, germination and roast-dry processes of malt. Also, extracts of functional ingredients such as free amino acids like GABA or dietary fibers like .beta.-glucan in the extract solution can be increased by optimizing the extraction temperature of malt root in the extract solvent. Therefore, using malt root and its extract obtained by performing the above controls as a part of manufacturing materials, food or food products, medical products and cosmetic products including lots of functional ingredients, and their processing methods can be provided.