Highly efficient recovery of nutritional proteins from Australian Rock Lobster heads (Jasus edwardsii) by integrating ultrasonic extraction and chitosan co-precipitation

Australian Rock lobster head by-products (LHBs) are underutilised, but they contain about 43.5% protein. An integrated process of ultrasonic intensification and chitosan co-precipitation was developed for the efficient protein recovery. This process efficiency is influenced by pH, the ratio of water/LHBs and chitosan concentration. Up to 99% lobster head proteins (LHPs) could be ultrasonically extracted within 5 min at a pH of 13 and water to LHBs ratio of 8 mL/g, of which 86.6% LHPs could be recovered by 250 mg/L chitosan co-precipitation. Nutritionally, 83.2% of LHPs are relatively intact proteins (molecular weights 50–150 kDa) enriched with umami, aromas and essential amino acids (EAAs – up to 38.9% - double the amount of adult requirements that is suggested by WHO/FAO), and low lysine/arginine ratio (1.0). The LHPs recovered have digestibility comparable to that of the egg protein and contain significantly lower toxic metals satisfying food safety standards, that makes this novel process and the extracted proteins very attractive for industrial applications.