Protein concentrate from Rhynchophorus phoenicislarvae: nutritional profile, protein identification, and emulsifying properties

The nutritional profile, protein identification of Rhynchophorus phoenicislarvae protein concentrate (Rp PC) were evaluated, as well as its emulsifying properties at different pH levels. Rp PC larvae was prepared from defatted insect flour through alkaline solubilization (pH 9.0) followed by acid precipitation (pH 4.5). The composition of Rp PC consisted of 70.66 g/100 g of proteins, 10.30 g/100 g of lipids (including triacylglycerols and free fatty acids at 3.09 g/100 g and 4.87 g/100 g, respectively), and 11.30 g/100 g of water. The amino acid profile of Rp PC showed high nutritional value, with 38.33 g/100 g of indispensable amino acids. Similarly, the polyunsaturated fatty acid content was 1.14 g/100 g, with an excellent n-6/n-3 ratio of 2.98. Among the identified proteins, some were muscle proteins while others were allergens. In terms of functional properties, Rp PC exhibited maximum solubility of 84.6 ± 2.0 g/100 g protein at pH 10.0, and minimum solubility of 11.6 ± 0.7 g/100 g protein at pH 4.0. Rp PC was able to form oil-in-water emulsions with monomodal particle size distributions and volume-weighted average diameters ranging from 2.2 ± 0.1 µm (at pH 9.0) to 4.8 ± 1.6 µm (at pH 5.0). Rp PC allowed for the stabilization of oil-in-water emulsions for at least 24 h at pH 7.0 and 9.0. Proteins extracted from Rhynchophorus phoenicislarvae at alkaline pH exhibited valuable nutritional and emulsifying properties, suggesting that Rp PC could be used as an emulsifying agent or in the formulation of new food products.