Black soldier fly (Hermetia illucens L.) larvae (BSFL) are capable to convert various organic waste into high-protein biomass. This study aimed to obtain protein hydrolysate from BSFL by pre-treatment with acid or alkaline solutions prior to hydrolysis utilizing a bromelain enzyme. Protein extraction from the BSFL was carried out using hydrochloric acid and sodium hydroxide with different extraction time (30–60 min) and temperature (25–50°C). The BSFL used in this study contains 32.11% protein with a maximum protein recovery of 38.42% after extraction with sodium hydroxide at 50°C for 30 min. The extracted protein solution was then hydrolyzed using bromelain enzyme at different concentrations (2–4%), pH (7–9), and hydrolysis time (4–24 h) to determine the greatest conditions for the hydrolysis procedure in terms of degree of hydrolysis and antioxidant activity of the protein hydrolysate using a response surface method with a face-centered central composite design. At the optimum conditions (3% enzyme, pH 8, 24 h), the degree of hydrolysis was 58.52%. The antioxidant activity of the protein hydrolysate was measured with an IC50 of 1.15%. The amino acid content of the protein was also identified and primarily consists of glutamic acid (3.7%), leucine (2.1%), and valine (2.0%).
Key words: antioxidant activity, black soldier fly, enzymatic hydrolysis, protein hydrolysate