Isolation of amaranth proteins

The use of whole and defatted amaranth flours for protein isolation is described. Extraction of proteins at pH 11 with NaOH and isoelectric precipitation between pH 4.5 and 5.5 with HCl gave the highest recoveries for both flours. Yields of salt-soluble proteins increased upon increasing the NaCl concentration to 0.8-1 M. Protein fractionation by an Osborne-modified procedure gave for both flours 46-49% albumins + globulins, 1-3% prolamins, and 30-33% glutelins. Albumins/globulins ratios, determined after dialysis, were about 2 and 1.7 for whole and defatted flours, respectively. Glutelins were the most abundant protein class in both flours.