Influence of pH and salt conditions on extraction efficiency and functional properties of Macrotermes nigeriensis protein concentrate for food applications

The search for alternative proteins from non-conventional sources for food processing has become important due to the shortage of conventional protein sources. Protein extractability from Macrotermes nigeriensis and its functional properties were investigated under various conditions of pH (2–10) and salt concentration (0.1–1.0 M). Extracted proteins were precipitated through pH adjustment and micellization, respectively. Results showed that maximum protein extractability was 68% and 62.1% at 0.5 M salt concentration and pH10.0, respectively. Salt-extracted protein-rich fraction (SP) had the highest protein composition (68.68 ± 0.41 g/100 g), seconded by alkaline-extracted protein-rich fraction (AP) (62.91 ± 0.53 g/100 g), compared with the raw and defatted fraction (34.36 ± 0.44 and 42.12 ± 0.15 g/100 g), respectively. The highest emulsion capacity (49%) and emulsion stability (35%) were recorded in alkaline pH 10.0. In comparison, the highest foaming capacity (24%) and foaming stability (16%) were recorded in the salt-extracted fraction at 6%. This information could be useful for further studies on the food application potential of proteins isolated from edible M. nigeriensis.