Countercurrent extraction‐isoelectric precipitation of sunflower seed protein isolates

A countercurrent extraction‐isoelectric precipitation procedure for the preparation of protein isolates from defatted sunflower seed meal is described. Using 0.04M NaOH and a solvent:meal ratio of 20:1, as much as 95% of meal nitrogen was extracted. Precipitation at pH 4.0 resulted in an isolate containing 88.4% of the meal protein. Using 0.1% sodium sulphite with the alkaline solution in the countercurrent extraction resulted in a white, bland and highly pure protein isolate. Isolated sunflower seed protein is limiting in the amino acid lysine, while other essential amino acids are present in amounts which meet the dietary requirements of chicks and human adults.