Effect of sonication pretreatment parameters and their optimization on the antioxidant activity ofHermitia illucenslarvae meal protein hydrolysates

Abstract

The study investigated the effect of sonication conditions on antioxidant activity of Hermetia illucens larvae meal protein hydrolysates. Three-factor three-level: pH (7–9), time (10–30 min), and temperature (25–55°C) were optimized. Box–Behnken's design was applied to optimize sonication treatment. Ferrous ion chelating activity (ICA), DPPH-radical scavenging activity (DPPHRSA), Hydroxyl radical scavenging activity (HRSA), and cupric ion chelating activity (CCA) were considered as responses. Findings demonstrated that sonication preceding enzymolysis significantly impacted on ICA, DPPHRSA, HRSA, and CCA. ANOVA showed the determination coefficient (R2) were 0.98 (ICA), 0.99 (DPPHRSA), 0.98 (HRSA), and 0.88 (CCA); demonstrating that the models were reasonably fit with experimental results. Optimum sonication conditions were pH (9), time (29.84 min), and temperature (54.93°C). For these conditions, the experimental data obtained [ICA (37.84%), DPPHRSA (43.19%), HRSA (71.01%), and CCA (68.93%)] were consistent with predicted values, higher than control, and supported by protein subunits, fluorescence spectra and microstructure. Practical applications With a rich nutrient profile, edible insects are potential ingredient for food applications. Hermetia illucens is one of the most encouraging edible insect species for incorporation in food products as it has several benefits to the environment, coupled with the already available knowhow for their rearing. With the prediction that in the next few decades insects will be reliable source of protein for humans and livestock, it is logical that the antioxidants activity of insect larvae meal proteins are investigated for new product development. Ultrasound is reported to enhance enzyme action in the preparation of bioactive hydrolysates/peptides. The present study showed that the use of ultrasonication pretreatment in the enzymatic hydrolysis of HILMP to generate hydrolysates with antioxidant constituents was efficient (likened to conventional approach). The study outcome could help the food and/or pharmaceutical industry to advance new bioactive products/ functional foods from HILMP hydrolysates.