Protein profile and allergenicity of edible silkworm (Bombyx mori) pupae as affected by gender, rearing substrate and processing

Edible insects, a traditionally food in Asia, can be a source of sustainable protein with low environmental impact [1]. Among these, the silkworm (Bombyx mori) pupae (SWP) has been included in the list of insect species with the biggest potential to be used as food and feed in the EU, even if a specific risk assessment should be performed, including the evaluation of the allergenic potential associated to entomophagy [2]. In this work, the protein profile of SWP was characterised by 2D-PAGE coupled to LC-MS/MS, to detect differences in protein expression related to the gender and to the diet (artificial or mulberry leaves). The SWP proteome analysis highlighted differences in abundance of several proteins, some of them strictly related to a single condition (gender or diet). Considering the sex-differentially regulated proteins, seven proteins better discriminated the sex effect (e.g. vitellogenin). As far as diet was concerned, five proteins were found highly related to the diet effect (e.g. bifunctional purine biosynthesis protein). Allergenicity of raw and fried SWP proteins was assessed by immunoblotting with sera of patients who were allergic to a different insect species (Tenebrio molitor). Processing (frying) was shown to enhance the IgE binding of both SWP reared on artificial and mulberry leaves diet. Moreover, overall proteomic investigation of SPW revealed the presence of three known allergens: arginine kinase, chitinase and 27-kDa glycoprotein. In conclusion, the study supports the importance of the comprehensive protein characterisation of novel foods, to assess the risk associated to their consumption.