Novel Insights on the Sustainable Wet Mode Fractionation of Black Soldier Fly Larvae (Hermetia illucens) into Lipids, Proteins and Chitin

The black soldier fly larvae (BSFL) is a sustainable ingredient for feed applications, biofuels, composite materials and other biobased products. Processing BSFL to obtain lipid and protein fractions with enhanced functional properties as a suitable replacement for conventional feed ingredients has gained considerable momentum. In this regard, a novel and sustainable wet mode fractionation (WMF) scheme for BSFL was explored. Fresh BSFL were steam blanched and pulped to obtain BSFL juice and juice press cake. Subsequent treatment of BSFL juice employing homogenization or enzyme incubation and further centrifugation resulted in the obtention of four different BSFL fractions (Lipid—LF; Cream—CF; Aqueous—AF; and Solid—SF). Total energy consumption for a batch BSFL (500 g) WMF process was 0.321 kWh. Aqueous and solid fractions were the predominant constituents of BSFL juice. Lauric acid (44.52–49.49%) and linoleic acid (19.12–20.12%) were the primary fatty acids present in BSFL lipids. Lipid hydrolysis was observed in lipids belonging to the solid (free fatty acids > triacylglycerides) and cream fractions. Aqueous fraction proteins (ctrl) displayed superior emulsion stability and foam capacity than other treatments. Juice press cake retained 60% of the total chitin content and the rest, 40%, was found in the solid fraction (ctrl). The material distribution of principal constituents in different fractions of the WMF process and amino acid profile was elucidated. Overall, the versatile WMF process proposed in this study involves simple unit operations to obtain functional ingredients from BSFL, which can be further explored by researchers and industry stakeholders.

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 H. illucens and B. mori oils. We adopted a vegetable diet for both insects: leftover vegetables and fruit for H. illucens and mulberry leaves for B. mori. First, alternative techniques to obtain a good oil extraction yield from the dried biomass of H. illucens larvae were tested. Traditional pressing resulted to be the best system to maximize the oil yield and it was successfully applied to B. mori pupae. Oil quality resulted comparable to that obtained with other extraction methods described in the literature. In the case of B. mori 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 Bacillus subtilis and Staphylococcus aureus to H. illucens and B. mori derived oils, whereas the growth of Gram-negative Pseudomonas aeruginosa and Escherichia coli 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.