Method and apparatus for isolating protein from glandless cottonseed

A storage protein isolate and a nonstorage protein concentrate are produced in a method where the nonstorage protein is extracted from an oilseed flour, such as cottonseed, using water. The pH of the nonstorage protein extract is then adjusted to about 4 to precipitate a nonstorage protein curd, leaving a nonstorage protein-containing whey. The nonstorage protein curd can then be passed through a spray dryer to produce the nonstorage protein concentrate. The residue from the original extraction step includes storage protein which is extracted in an alkali solution. After removing insoluble residues, the storage protein extract is intermixed with the nonstorage protein whey and subjected to filtration through a semipermeable membrane to produce the storage protein isolate.U