Cereal Chem 55:469 - 480.  |  VIEW ARTICLE
Nature of the Residual Protein Associated with Starch Fractions from Air-Classified Field Peas.

R. D. Reichert and C. G. Youngs. Copyright 1978 by the American Association of Cereal Chemists, Inc. 

Smooth-seeded green field peas (Pisum sativum) were pin milled and air-classified to yield a green starch fraction and an off-white protein concentrate. Scanning electron microscopy of the starch fraction revealed protein bodies attached to starch granules, agglomerates, and an uneven granular surface. Repeated pin milling and air classification of this starch fraction removed the protein bodies and reduced the number of agglomerates. Partition of the chlorophyll, which is associated with chloroplast membrane structures, and a calculation based on the chlorophyll/starch ratio of the flour and air-classified starch fraction indicated that 84% of chloroplast membrane residues remained with the starch fraction after initial air classification. Water washing the air-classified starch suspended these membraneous residues and solubilized most of the remainder of the nitrogen. Amino acid analysis of adherent protein in air-classified starch indicated proportionately more acidic and less basic amino acids than in the air-classified protein concentrate. Polyacrylamide gel electrophoretic patterns and nitrogen solubility of the two protein types were markedly different.