Bioactivities of black soldier fly larvae protein hydrolysate

Abstract

One of the potential insects for feed and food sources is the Black Soldier Fly (BSF) (Hermetia illucens). The BSF originated in South America and has now spread to many tropical countries. The BSF larvae (BSFL) had attracted much attention due to their good nutrient content and were recently reported as having useful bioactivities. BSFL has been widely used as feed and has been found to reduce bad smells associated with the growth of pathogenic microbes. The high protein content in BSFL is advantageous in the production of bioactive peptides. This research aimed to extract and hydrolyze the protein from BSFL with protease enzyme to produce protein hydrolysate or peptides with antioxidant and antibacterial activities. The antioxidant activity was measured using DPPH and FRAP, while the antibacterial was analyzed using the agar well diffusion method. BSFL was hydrolyzed with bromelain extracted from pineapple or commercial enzyme (Enzyplex). The IC50 shown by protein hydrolysate was 9.43±0.84% (v/v) or 0.72 mg/mL. The FRAP value was 521.21±264.53 µM for BSFL protein without enzyme addition, 792.14±291.02 for BSFL with the addition of bromelain, and 5,352.114±861.99 µM for BSFL with the addition of Enzyplex. The addition of bromelain increased the FRAP value 1.2 times, while the addition of Enzyplex increased the FRAP value 10.2 times. The antibacterial activity indicated that protein hydrolysate with phosphate buffer pH 8 at 50℃ and 24 hrs incubation showed the highest antibacterial activity to the lowest are Vibrio cholerae, Bacillus cereus and Staphylococcus aureus, respectively. The results suggest that BSFL has antibacterial and antioxidant bioactivities using bromelain extracted from pineapple and Enzyplex, a commercial enzyme that contains protease, lipase and amylase. Using Enzyplex as an enzyme to hydrolyze BFSL shows a very high antioxidant capacity compared to bromelain as an enzyme. This suggests that more protein and other macromolecules contribute to the antioxidant capacity. Using bromelain as an enzyme to hydrolyze BSFL, shows that BSFL peptide has higher antibacterial activity in gramnegative bacteria.