Properties of protein concentrates and hydrolysates from Amaranthus and Buckwheat

Protein concentrates and pepsin hydrolysates were made after isoelectric pr ecipitation of the proteinaceous liquor from wet-milling of grain of five A maranthus and one buckwheat genotype. The Amaranthus protein concentrates e xhibited better solubility, foaming, and emulsification than two commercial soy protein controls. Many protein properties depend on solubility, and Am aranthus protein concentrates were more soluble than soy protein isolate. T he buckwheat protein concentrate was highly soluble with excellent emulsifi cation, but poor foaming ability. Partial pepsin hydrolysis further improve d solubility of the protein concentrates and also altered their foaming pro perty. Fractionation and subsequent characterization of protein concentrate s revealed that glutelins, albumins, and globulins predominated, with prola mins present in minor quantity. SDS-PAGE showed that globulins and glutelin s were comprised of several subunits with varying molecular weights from re latively high to low while albumins were mostly of low molecular weight. Th e prolamin fraction of the buckwheat concentrate was comprised of intermedi ate to low molecular weight subunits while those of Amaranthus concentrates were only of low molecular weight. This study demonstrated the feasibility of producing potentially useful functional protein concentrates as by-prod uct of Amaranthus and buckwheat starch extraction. (C) 1999 Elsevier Scienc e B.V. All rights reserved.