Black soldier fly (Hermetia illucens) larvae accumulate bioactive compounds that modulate antioxidant activity when reared with bioactive agrifood by-products

Abstract

The effect of feeding Hermetia illucens larvae (black soldier fly, BSFL) with by-products from olive oil (dry olive leaves, OL; full-fat dry olive pomace, OP) or quinoa (quinoa husk, QH) on the bioaccumulation of bioactive compounds and antioxidant activity of the meals was evaluated. Diets were formulated with different percentages of inclusion (OL15, OL30, OL50; OP30, OP50, OP70, OP90; QH15, QH30, QH50). Antioxidant activity (DPPH and ABTS methods), total phenolic compounds (TPC), targeted bioactive compounds analysis, and estimation of efficiency of bioaccumulation (EB) were performed, and compared to the experimental substrates. TPC were evidenced in all meals, but without a clear patter relationship with the diets. All meals exhibited DPPH and ABTS antioxidant activity. Improvements on DPPH inhibition were found for most treatments, especially remarkable for OP90. No improvement was observed for ABTS inhibition. BSFL meals accumulated bioactive compounds from olive oil by-products but, while diets were rich in phenolic compounds (oleuropein or hydroxytyrosol) and minor in pentacyclic tritepernes, the meals mainly accumulated pentacyclic triterpenes (mainly oleanolic acid and maslinic acids). The total bioactive EB ranged 0.6-3.5 %, with net accumulated total content of 46-383 mg/100 g of meal, depending on the diet. Additionally, total bioactive content correlated strongly with the DPPH antioxidant activity of the meals (r = -0.929, p < 0.05). The potential of dietary strategies of BSFL to enhance the bioactive profile and bioactivity is demonstrated. Moreover, when feeding bioactive-rich by-products, such as those from olive oil, these strategies for health value of insects simultaneously align with circular economy practices.

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