A method comprising treating a potato wastewater stream containing suspended free starch particles with a potato starch-complexing emulsifier to form agglomerated starch particle-emulsifier complexes, and separating the complexes from the remainder of said wastewater stream. Also the separated starch complex suitable for human or animal consumption alone or in combination with other food ingredients. In various embodiments, the products comprise (a) at least about 2000 mg/100 g, BDS, glutamic acid; and/or (b) at least about 2500 mg/100 g, BDS, aspartic acid; and/or (c) at least about 10 g/100 g, BDS, total protein.