Production of Nutritional Protein Hydrolysates by Fermentation of Black Soldier Fly Larvae

The black soldier fly (<i>Hermetia illucens</i>) has become one of the most promising alternative protein sources in the feed and food industry. The aim of this work was to utilize microbial fermentation to enhance the nutritional properties of black soldier fly larvae (BSFL) as a food ingredient for human consumption by optimizing the amino acid profile and small peptide content. Free amino acids (FAA) have a critical role in human nutrition and bioavailability. Unlike whole proteins that require enzymatic breakdown in the digestive tract, FAA are directly absorbable by the small intestine, allowing for rapid utilization in protein synthesis and metabolic functions. BSFL pastes were fermented using <i>Lacticaseibacillus paracasei</i> (PCB 030) or a mixed starter culture preparation, and results were compared to pea protein and BSFL pastes that were enzymatically hydrolyzed. The resultant hydrolyzed BSFL pastes were analyzed for free amino acids and small peptides. The <i>L. paracasei</i> PCB 030 fermented BSFL pastes yielded significantly higher amounts of free amino acids than the control or pastes fermented using a commercial starter culture (named F-LC). The increased FAA availability in fermented BSFL makes it a more efficient protein source for human consumption. The <i>L. paracasei</i> PCB 030 fermented pastes showed an increase in small peptides after three days fermentation; nearly 80% of normalized abundances of small peptides increased by over 100 times compared to day zero (before the fermentation started). Over 90% of these small peptides consisted of more than 50% hydrophobic amino acids, which may contribute to their antioxidant and antibacterial properties. This study provides a promising and industrially practical process for hydrolyzing BSFL protein to yield a functional protein hydrolysate with an enhanced nutritional profile.