Production of protein-rich pulse ingredients through dry fractionation: A review

Abstract

As the global protein demand is expected to double in the coming decades due to the increasing population and new consumer trends, pulses have been identified as a nutritious and inexpensive alternative source of protein. With the increasing interest in plant-based proteins, dry fractionation has shown promising results as a sustainable method to produce native protein fractions for food applications. The objective of this review is to describe the studied strategies to produce protein-rich pulse ingredients through dry fractionation. Dehulling is used to separate the seed coat which contains most of the fiber. Dry or wet pretreatment methods can utilize to facilitate the better separation of seed coat during dehulling. Then dehulled material can mill and separate into two main fractions which contain, one with relatively large starch granules and the other with the smaller protein matrix fragments with fiber plus embedded starch granules. The milling step needs to be carefully chosen to break up the cotyledon into a suitable particle size without severely damaging starch granules. Air classification, sieving, and electrostatic separation are used to increase the purity of the protein fractions. During separation, air classification and sieving use the particle size and/or density, where electrostatic separation uses the charging behavior of particles. Protein-rich pulse ingredients can be sustainably produced by optimizing the dehulling, milling, separation techniques, hybrid fractionation, and functional fractionation. However, dry fractionation methods should continue to be explored, to facilitate the better separation of protein fractions in view of final applications.