Dry fractionation of chickpea flour: Impact of de-oiling and flow aids

Air classified chickpea protein concentrates often lack the separation efficiency of other starch-rich pulses. We subjected chickpea flour to de-oiling or to blending with different types and concentrations of silica flow aids to reduce its cohesion and to increase its dispersibility in air. Air classification enriched protein to a content of 45%. Initial protein yields below 25% increased to 70% upon extensive de-oiling, and this de-oiled ingredient containing 51% protein was enriched to 56% by electrostatic separation. Alternatively, nanosized flow aids doubled the initial protein yield. SEM-EDS image analysis revealed that higher silica concentrations increased the accumulation of nanoparticles onto flour particles, which lowered the flour’s basic flow energy and moderately increased its dispersibility. This reduced fouling during air classification, but the protein yield levelled off with increasing silica concentrations because the microstructure was not disentangled further. Silica addition during milling rendered post-milling blending unnecessary, without compromising the protein yield.