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In a contest in which the interest in renewable raw materials is growing considerably, solid state fermentation is often applied to valorize organic wastes, thanks to the count-less benefits this process can bring to the unexploited biomasses, such as the microbial stabilization and the simultaneous production of antibiotics and bioactive compounds. Hermetia illucens (Black Soldier Fly, BSF) is a non-pathogenic insect that is often used in the bio-conversion processes of residual biomasses into feed ingredients. In this work, for the first time, a solid-state fermentation was conducted with 2 lactic acid bacteria (LAB) strains, isolated from food, on insect prepupae and insect-derived wastes (pupal membranes and adult insects at the end-of-life cycle) produced during bioconversion processes. The present work was undertaken to study the difference in the molecular composition between fermented and unfermented insect-derived waste materials, focusing on lipid, protein, and chitin fraction. The bulk evaluation of fat, protein, moisture, and ashes composition of insect-derived biomasses was carried out using standard procedures (AOAC, 2002). Fatty acid pro-files were determined by GC-MS, whereas total amino acid analysis, glucosamine monomer content (after chitin hydrolysis) and the formation of possible peptides or chi-tin oligomers was carried out by LC/ESI-MS methodologies. A metabolomics approach by 1H NMR was also applied to get further insight in both lipid and polar insect fractions. The results showed that the lipid fraction is the most affected by the fermentation: the fermented biomass had a higher percentage of lipids and a more complex fatty acid profile as compared to unfermented mass, with a fatty acid composition shifting from a typical one from BSF to a more typical one for LAB. Also, the protein fraction changes upon fermentation, especially in the amino acid composition, while the production of peptides was very limited. On the contrary no chitin oligomers formation was observed after the fermentation process. This study shows how fermentation can modify the molecular composition of insect-derived waste, exploiting the typical metabolic behavior of fermenting bacteria. Further studied are encouraged to better understand possible functional properties of insect fermented biomasses and related applications. [ABSTRACT FROM AUTHOR]

Nowadays, the insect mass rearing production is promoted not only for the insect nutritional value, but also for their ability to bioconvert agro-food leftovers, which otherwise would be discarded, into high valuable proteins and fats. Previous studies have already demonstrated the potentiality of tailoring a promising diet by mixing agro-food leftovers in order to maximize the feed conversion rate, as well as to improve the final nutritional value of Hermetia illucens larvae (BSFL). In the present work, we evaluated the potential production of carotenoid-rich BSFL by rearing them on specific agro-food leftovers rich in α- and β-carotene, lycopene, lutein and zeaxanthin. The results showed that the carotenoid concentration in BSFL was strictly correlated with the carotenoid content in the insect growth media. Among the different substrates, tomato and carrot leftovers allowed to obtain BSFL with a total carotenoid content 230% higher than the amount detected in the BSFL grown in the control diet. Furthermore, we demonstrated that the killing method plays a key role in preserving the BSFL carotenoid content, with dry heating (100 °C for 2 minutes) resulting in a significantly higher lycopene, α- and β-carotene content compared to blanching (100 °C for 40 seconds) and freezing (-20 °C). These results clearly support the exploitation and valorisation of agro-food leftovers for the production of BSFL naturally rich in carotenoids with enhanced bioactive properties, to be used for specific feed and food purposes. This work was done in the framework of the project "FLIES4VALUE" co-funded by POR FESR, Program 2014-2020 (Italy), Axis 1, Action 1.2.2 Call for Research Grouping. [ABSTRACT FROM AUTHOR]