Toward the design of insect-based meat analogue: The role of calcium and temperature in coagulation behavior of Alphitobius diaperinus proteins

This study focused on the coagulation behavior of protein from larvae of Alphitobius diaperinus. The effect of incremental CaCl₂ concentration (10, 15, 20 and 20 mmol/L) and temperature (90, 100 °C) on physical-chemical properties of insect coagula was investigated. A yield between 76 and 83 g of coagulum was obtained from 100 g of fresh larvae, decreasing with higher temperature and CaCl₂. Protein-protein interactions and microstructure of coagula were analyzed respectively by means of protein solubility, SDS-PAGE and SEM. When higher temperature was applied, hydrophobic interactions and disulphide bonds increased due to a larger degree of protein denaturation, thereby contributing to the formation of large protein aggregates. Thus, significant increase in hardness of the coagula was observed, with specimens at 20 mmol/L CaCl₂ being more than twice harder at 100 °C than at 90 °C. Moreover, proteins homologous to actin and tropomyosin contributed to the coagulum structure by hydrophobic interactions, whereas hemolymph proteins formed disulphide bonds. Increasing concentration of CaCl₂ from 10 to 20 mmol/L, at 100 °C, displayed a smoother network that increased coagula hardness from 1200 to 2900 g respectively. Results of this study provide important information for the product development in relation to insect protein-based meat analogues.