Characterization of Black Soldier Fly Larvae Protein for Functional Food

Abstract

Black Soldier Fly (BSF; Hermetia illucens) is wasp-like fly that is useful to manage extensive amounts of animal manure. BSF is not a mechanical vector of disease as adult BSF do not feed and survive merely on fat stores from their larval stage. BSF and their larvae has gained intensifying attention within these past few years due to their high contents of protein and lipid that may result in a high-value feed ingredient and potential uses in many applications. Indonesia is a country with rapid population growth, economic development, and urbanization. However, Indonesia also possesses nutritional problems such as malnutrition in children. Therefore, demands for quality food arises. As demands arise, meat and dairy production should also be increased. However, the increase in meat and dairy production will then lead to the substantial increase in demand for protein-rich animal feeds. Hence, alternative protein-rich food and feed that is economically viable such as those sourced from BSF is needed. However, the study regarding the extraction and characterization of protein from BSF for its utilization in functional food are not done yet. This research aims to (1) characterize the protein profile of BSF larvae and (2) identify the digestibility of protein extracted from BSF larvae. This research was conducted in two stages: first and second stage research. First stage research was aimed to characterize the isolated BSFL protein. Second stage research was aimed to conduct the in-vitro simulated digestion of BSFL protein and determining its eligibility for functional food. Data processing was done using one-way ANOVA, followed by Duncan’s Multiple Range Test. Black Soldier Fly Larvae (BSFL) protein in this research had 73.46 ± 0.20% protein content. Through SDS-PAGE analysis, BSFL protein showed thick bands at 35 kDa and below, indicating the presence of low molecular weight protein/peptides that refers to the glutelin proteins. BSFL protein hydrolysed with external digestive enzymes showed 97.48 ± 0.04% digestibility. Whey protein isolate as a protein control in the human in-vitro digestion process showed 97.84 ± 0.03% digestibility. Hence, comparing with the digestibility of whey protein isolate, BSFL protein can be regarded as a good protein. The digested BSFL protein no longer displayed protein bands above 15 kDa in the SDS-PAGE analysis indicating its high digestibility. BSFL extract contained internal enzyme with an α-amylase activity of 48.93 ± 1.57 U/ml, pepsin activity of 2.04 ± 0.005 U/ml, and pancreatin activity of 1.65 ± 0.006 U/ml. The in situ internal enzyme activity was also observed in the zymogram analysis. Upon zymogram analysis, BSFL internal enzyme exhibited activity at 50-75 kDa and under 25 kDa. BSFL protein hydrolysed with BSFL internal enzyme displayed 44.1 ± 0.21% digestibility, still leaving protein bands at 35, 25, and 15 kDa. Overall, experimental data suggested the exceptional potencies of BSFL protein as food alternative protein source as it was well digested by external digestive enzyme.