Black soldier fly larvae (Hermetia Illucens) as a sustainable and concentrated source of bioavailable lutein for feed
Black soldier fly larvae (BSFL) are increasingly used to recycle and convert food waste into feed. We attempted to assess whether they can bioaccumulate lutein, a xanthophyll used as a food coloring, and whether it is then sufficiently bioavailable for an economically relevant incorporation of BSFL into feed. Vegetables and larvae lutein concentrations were measured by HPLC. Lutein bioaccessibility was estimated by in vitro digestion and lutein absorption efficiency by Caco-2 cells. BSFL were at least as rich, and sometimes richer (P < 0.05), in lutein than the vegetables they were reared on. For example, the larvae reared on kale contained 160.2 ± 3.4 mg/kg vs 23.0 ± 3.5 mg/kg of lutein, on a fresh weight basis, for the kale substrate. For the same substrate, lutein bioaccessibility was not statistically different between BSFL and the substrate (respectively 14.8 ± 1.2% and 16.2 ± 2.8%; P = 0.7). Finally, by considering the lutein concentration in BSFL enriched in lutein and in lutein-rich substrates, as well as the bioaccessibility and intestinal absorption efficiency of lutein contained in these matrices, it was estimated that consumption of lutein-enriched larvae would lead to a theoretical amount of absorbed lutein about 2 to 13 times higher compared to that following the consumption of an equal quantity of lutein-rich vegetables. Thus, BSFL can be used as a sustainable and concentrated source of bioavailable lutein for feed and, indirectly, for food.