Effect of extraction condition on technological properties of protein from Protaetia brevitarsis larvae

Abstract

Alternative food sources are garnering increasing interest owing to overpopulation and environmental stresses. Edible insects are a promising alternative protein source. In this study, we evaluated the effect of pH and NaCl concentration on the quality and technical properties of extracted Protaetia brevitarsis protein. Nine different solutions were used to extract edible insect protein (pH 1, 4, 7, 10, and 14 and 0, 0.1, 0.5, and 1 M NaCl). The pH of the extracted protein increased with increasing pH (1.12±0.02 to 12.81±0.03) and decreasing NaCl concentration (6.52±0.02 to 6.89±0.01). Colour difference increased when deviating from neutral pH and 0 M NaCl. Further, surface hydrophobicity (μg) and solubility (mg/ml) of the protein decreased at pH 1 (12.25±1.39 μg and 0.74±0.08 mg/ml) and 14 (20.62±1.48 μg and 0.18±0.02 mg/ml) compared with pH 7 (71.81±1.76 μg and 1.26±0.22 mg/ml). Higher pH and NaCl concentrations yielded higher thermal stability. Foaming capacity was the highest at 0.5 (110.5±0.71%) and 1 M (100.5±10.61%) NaCl, and pH 14 (122.5±3.54%), followed by that at pH 1 (72.50±3.54%), although with low stability. Furthermore, emulsifying capacity and stability of the protein increased when deviating from pH 4. Therefore, the protein of P. brevitarsis had high functionality when extracted at highly alkaline conditions using NaCl.