Effect of Alkaline Extraction–Isoelectric Precipitation and Salt-Assisted Extraction on Physicochemical and Techno-Functional Properties of Black Soldier Fly Larvae Proteins

Black soldier fly (BSF) larvae are an increasingly popular source of protein in the food industry, and they are showing great potential as a sustainable alternative to traditional protein sources. However, to fully utilize the potential of insect protein as food, it is important to improve their functional characteristics. The purpose of this study was to thoroughly examine the influence of alkaline extraction and isoelectric precipitation methods assisted by salting-in (NaCl) and salting-out ((NH4)2SO4) techniques on the functional properties of BSF larvae proteins. The physicochemical and techno−functional properties of the proteins were determined. The addition of (NH4)2SO4 significantly (p < 0.05) influenced the solubility of protein, particularly at pH 2, suggesting its potential applicability in acidic food systems. Surface hydrophobicity was modulated by salt treatment, with salting-out methods reducing hydrophobicity and affecting protein functionality. The correlation analysis demonstrated a significant positive relationship (p < 0.05) between the various functional properties, emphasizing their interconnected nature. Foam capacity and foam stability showed a positive relationship with protein solubility at pH 4 (r = 0.88, p < 0.05; r = 0.74, p < 0.01, respectively). These findings imply the potential use of BSF larvae proteins in food formulations, especially considering the positive correlations observed between emulsification properties, solubility, and surface hydrophobicity. The identified correlations lay the groundwork for further exploration of BSF larvae proteins as sustainable functional ingredients in food applications, aligning with growing interest in alternative protein sources for the food industry.