Synthesis and Fractionation of Protein Hydrolysate from Hermetia illucens L. Pre-treated with Lactobacillus spp

This study aimed to investigate the effects of fermentation pretreatment using Lactobacillus spp. on the protein content of black soldier fly larvae as well as the protein recovery, degree of hydrolysis, and amino acid composition of protein hydrolysate from these larvae. Solid state fermentation of black soldier fly larvae with Lactobacillus spp. carried out for 72 h at 37℃ increased the protein and fat content from 32.35 to 36.75–41.99% and 36.91 to 40.03–41.99%, respectively. Protein content in the fermented samples was extracted using an alkaline extraction method, which resulted in a protein recovery of 31.41 to 35.99%. The protein extract was then hydrolyzed using bromelain enzymes for 24 h to produce protein hydrolysates with a degree of hydrolysis ranging from 47.64 to 52.61%. The protein hydrolysate was further fractionated using size-exclusion chromatography with a flow rate of 0.5 to 1.5 mL/min. The protein concentration of each fraction was determined using a UV-visible spectrophotometer, and the results varied from 0.004 to 2.03 mg/mL, with the highest protein concentration for each fermented sample observed at a chromatography flow rate of 1-1.5 mL/min. The amino acid composition of the fractionated protein hydrolysate was determined using ultra-high-performance liquid chromatography. The results show that the fractionated protein hydrolysates fermented with Lactobacillus spp. contained several amino acids, such as glycine and L-methionine, which were significantly different from the unfermented samples. The findings highlight that fermentation of black soldier fly larvae using Lactobacillus spp. positively influenced the protein and amino acid composition of protein hydrolysate from black soldier fly larvae.

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