## 3 Results and Discussion
### Emulsifying Properties  
Emulsification is the process by which proteins enable and maintain the interface between oil and water. Generally, soluble, amphiphilic, and versatile proteins serve as effective emulsifiers [48]. The emulsifying properties of BSF larvae were evaluated using the emulsifying activity index (EAI) and emulsion stability index (ESI), as shown in Figure 5. Our protein isolates exhibited noteworthy (\(p<0.05\)) variations in EAI values, spanning from 32.50 to 87.78 m\({}^{2}\)/g (Figure 5). These values corresponded to, or surpassed, those reported for other edible insects, including _Patanga succineta_ (23.23 m\({}^{2}\)/g) [49], _Gryllodes sigillatus_ (32 m\({}^{2}\)/g) [23], and _Chondracris roseaprunner_ (36.96 m\({}^{2}\)/g) [49]. The salting-out proteins demonstrated the most promising results, making them suitable candidates for emulsifying agents.  
Generally speaking, the phenomenon of emulsification can be attributed to the adsorption of proteins at the interface between oil droplets and the surrounding water in emulsions [24]. The observation that the salting-out group exhibited a higher EAI could be attributed to the greater availability of small, soluble proteins at the oil-water interface  
Figure 4: Effect of extraction methods on foaming capacity and stability of black soldier fly larvae isolates obtained by AAF (alkaline–acid extraction), AAFSI (salting-in technique), AAFSO (salting-out technique), and AAFSISO (salting-in and out technique). Various letters (a, b, c, d) point to noteworthy variations at \(p<0.05\). Error bars show standard deviation.  
due to increased protein solubility [50]. The disparities in EAI are thought to be related to differences in surface hydrophobicity and protein-protein/oil interactions [51; 52]. Ref. [51] suggested that proteins with a high surface hydrophobicity are prone to be adsorbed at the oil-water interface, which would enhance the emulsification effect. According to [51], a robust correlation exists between high surface hydrophobicity and a high emulsion stability index, which is consistent with our findings. Ref. [52] noted that an increase in the ionic strength of the extraction solution can enhance the shielding of surface charge, leading to an increase in protein-protein interactions while reducing protein-oil interactions. The stability of an emulsion is determined by the balance between repulsive and intramolecular forces at the water-oil interface, which can be influenced by various factors such as ionic strength, pH, amino acid polarity, and protein composition [53].  
Our results, as illustrated by the ESI values, showed that the AAF and AAFSI proteins exhibited higher values (62.28% and 70.12%, respectively) compared to the _T. molitor_ proteins (51.31%), as previously reported by [36] (Figure 5). Additionally, the fastest destabilization of the emulsions was observed in the AAFSO proteins, which was more than twice that of the AAFSI proteins (Figure 5). The results obtained from the salting-out-assisted treatments revealed a decrease in ESI, which is consistent with previous studies that found that proteins isolated by isoelectric precipitation had higher ESI levels than those isolated by ammonium sulfate precipitation [32]. The high hydrophobicity levels of BSF larvae isolates may also enhance protein adsorption at the oil/water interface, resulting in a decrease in interfacial tension and an increase in ESI levels [15]. Presently, casein and whey proteins are the most commonly utilized emulsifiers in the food industry. However, researchers are continuing to explore alternative protein sources that could potentially replace these traditional options. The BSF larvae extracts studied in this research produced similar results and could be used as alternative protein emulsifiers in both existing food products and new formulations.