Protein extraction from edible insects: Implications for IgE-binding capacity

Edible insects are attracting increasing interest as sustainable alternative protein sources. Despite being considered a safe food for most population, their consumption can pose health risks for allergic patients. This work focused on isolating proteins from the four-European Union approved insects (Tenebrio molitor, Alphitobius diaperinus, Acheta domesticus, and Locusta migratoria) and evaluating their potential immunoglobulin E (IgE)-reactivity with crustacean-allergic patients' sera. For this purpose, 16 protein extraction protocols were applied to the four insect species. A simple/fast extraction protocol (3.5 h) using 100 mM Tris-HCl + 4 % SDS (pH 7.6) buffer in a single incubation step (60 °C/2 h) proved to be the most efficient in isolating IgE-reactive proteins of the four species. Most of the proteins extracted with the proposed protocol showed IgE-reactivity with sera from crustacean-allergic patients. Their IgE-binding capacity was attributed mainly to conformational epitopes, with protein denaturation enhancing epitope accessibility and/or exposing linear epitopes.