Isolation and proteomic characterization of tropomyosin extracted from edible insect protein.

Edible insects are considered promising sustainable protein sources. Thermal treatments and proteolysis are commonly used to improve their safety and quality. However, their allergenicity remains mostly unexplored. Tropomyosin, a major insect pan-allergen, can be used to study processing effects on its immunoreactivity. In this study, selective precipitation was used to extract tropomyosin from heated and protease-treated crickets. Immunoinformatics predicted 31 epitope regions, while proteomic analysis suggested decreased amounts of intact epitope regions in microwave-heated/protease-treated crickets. Tropomyosin peptide sequences were identified in higher abundance in convection-heated samples. Finally, tropomyosin immunoreactivity by immunoblotting and ELISA, revealed that protease treatments under microwave heating had lower (p < 0.05) IgE and IgG reactivity. Based on results, processing insects using proteolysis and microwave-heating could be effective for generating hypoallergenic cricket protein ingredients. The use of proteomics and bioinformatics proved to be useful tools in understanding the impact of processing on allergenic reactivity of insect proteins.

Functional properties of tropical banded cricket (Gryllodes sigillatus) protein hydrolysates.

Recently, the benefits of entomophagy have been widely discussed. Due to western cultures' reluctance, entomophagy practices are leaning more towards incorporating insects into food products. In this study, whole crickets (Gryllodes sigillatus) were hydrolyzed with alcalase at 0.5, 1.5, and 3.0% (w/w) for 30, 60, and 90min. Degree of hydrolysis (DH), amino acid composition, solubility, emulsion and foaming properties were evaluated. Hydrolysis produced peptides with 26-52% DH compared to the control containing no enzyme (5% DH). Protein solubility of hydrolysates improved (p<0.05) over a range of pH's, exhibiting >30% soluble protein at pH 3 and 7 and 50-90% at alkaline pH, compared with the control. Emulsion activity index ranged from 7 to 32m2/g, while foamability ranged from 100 to 155% for all hydrolysates. These improved functional properties demonstrate the potential to develop cricket protein hydrolysates as a source of functional alternative protein in food ingredient formulations.