Influence of the fractionation method on the protein composition and functional properties

Mild wet fractionation can separate pea proteins into a soluble and a non-soluble fraction. Soluble proteins and solutes are extracted into the soluble protein fraction, insoluble proteins are collected in the non-soluble protein fraction. The protein composition in the respective fractions was investigated by further fractionating the protein fractions with isoelectric precipitation. The molecular mass of the proteins in the fractions was determined by SDS-PAGE and size exclusion chromatography. The protein fractions' solubility was determined in excess water, and the gelation properties were investigated at the same protein concentration. With mild wet fractionation, compared to conventional wet fractionation, both globulins and albumins are extracted. The protein fractions were mixtures of both proteins, although the non-soluble protein fraction contained mainly globulins. Solubility and gelation properties varied with protein type, composition and protein state; isoelectric precipitation decreased the gelation capacity of the protein fractions.