Effect of alkaline pH-shifting process on extraction rate, structural, and functional properties of black soldier fly (Hermetia illucens) larvae protein

The effect of pH-shifting (10.5, 11.0, 11.5, 12.0, and 12.5) on the extraction rate, structural, and functional properties of black soldier fly larvae protein (BSFLP) was studied. The results showed that alkaline pH-shifting increased the extraction rate of BSFLP by 135–1080% (relative to the control). Fourier transform infrared and circular dichroism spectroscopy showed structural changes in BSFLP. The protein extracted under extreme alkaline pH (12.0, 12.5) was partially unfolded, leading to a substantial reduction in the disulfide bonds, hydrogen bonds, α-helix, and particle size; whereas a notable increase in the absolute zeta potential, surface hydrophobicity, and protein dispersion were realized. The solubility, foaming, and emulsifying properties of BSFLP were significantly improved (especially at pH 12.5). The outcome of the study provides a better understanding of the changes in structural traits and functionality of BSFLP – important for its utilization in the industry.