Mechanical Processing of Hermetia illucens Larvae and Bombyx mori Pupae Produces Oils with Antimicrobial Activity

The aim of this work was to develop processing methods that safeguard the quality and antimicrobial properties of and oils. We adopted a vegetable diet for both insects: leftover vegetables and fruit for and mulberry leaves for . First, alternative techniques to obtain a good oil extraction yield from the dried biomass of larvae were tested. Traditional pressing resulted to be the best system to maximize the oil yield and it was successfully applied to pupae. Oil quality resulted comparable to that obtained with other extraction methods described in the literature. In the case of pupae, different treatments and preservation periods were investigated to evaluate their influence on the oil composition and quality. Interestingly, agar diffusion assays demonstrated the sensitivity of Gram-positive and to and derived oils, whereas the growth of Gram-negative and was not affected. This study confirms that fat and other active compounds of the oil extracted by hot pressing could represent effective antimicrobials against bacteria, a relevant result if we consider that they are by-products of the protein extraction process in the feed industry.