High hydrostatic pressure for decontamination of soluble insect proteins prevents protein denaturation better than blanching

Abstract

Insect production currently involves thermal processes to ensure microbial safety and inactivate endogenous enzymes, but these processes negatively affect the protein's technological properties. Therefore, this study compared high hydrostatic pressure (HHP) at 200/400/600 MPa for 10 min to blanching at 90 °C for 10 min, on soluble protein fractions (pH 3) from house crickets (Acheta domesticus) and lesser mealworms (Alphitobius diaperinus). HHP significantly reduced the microbial load, especially at 400 and 600 MPa. For aerobic counts of mealworms, blanching (from ∼6 to ∼3 log CFU/mL) was more effective than HHP (∼4 log CFU/mL). HHP preserved the secondary protein structure better than blanching, but was less effective in protease inactivation, though only evident in mealworms. HHP did not affect foaming and emulsification properties but improved protein solubility after pH adjustment to 7 compared to untreated fractions by 14–22%. We thus demonstrate that HHP can be an effective alternative to conventional blanching treatments. The emerging edible insect industry is currently struggling with several challenges. Conventional thermal processes that are often applied can negatively affect the techno-functional protein properties. We demonstrated that high hydrostatic pressure (HHP) can be an effective milder alternative to thermal processes. The evaluated blanching condition did not always negatively affect the functional protein properties, and blanching was more effective in protease inactivation compared to HHP for lesser mealworms. HHP can be of industrial relevance for inactivating house cricket fractions with high protein solubility intended for emulsion applications. Blanching could be better suited to provide proteolytically stable fractions.

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