Leg muscles of migratory locust (Locusta migratoria) as a protein source: Extraction, protein composition and foaming...

Migratory locust (Locusta migratoria) is an edible insect species that is usually consumed at the adult developmental stage and represents a valuable source of proteins. Locusts can be processed into food ingredients or directly consumed after removal of legs and wings. Legs represent a unique matrix, which comprises a chitin-based exoskeleton typical for insects and muscle tissues commonly occurring also in other animals. Muscle proteins can be easily extracted from traditional animal sources, but the efficiency of these methods for locust legs as well as the functional characteristics of the resulting protein extracts have not been previously explored. This study first compared protein extraction methods at acid, alkaline, and salt-assisted conditions. All three methods resulted in a significantly higher extraction yield from locust leg muscles (0.465-0.595 g/g) than from whole locusts (0.061-0.125 g/g). Shotgun proteomics of the protein fraction extracted at alkaline conditions assigned 310 muscle proteins, comprising components assigned to energy and carbon metabolism, as well as to skeletal, protein folding, membrane trafficking, and cell adhesion functions. The techno-functional potential of locust leg muscles was assessed by a foamability assay. Foam stability of locust leg extracts varied as a function of pH extraction and re-solubilization conditions and was significantly higher (58.3-70.8 %) than for whey proteins taken as a benchmark (38.3-51.7 %); foam capacity at t = 0 h was in the range of 48.6-68.8 %. This study demonstrates that locust legs, which can be a by-product of locust consumption or processing, should be considered a rich source of muscle proteins with promising technological functionality.