*2.11. Emulsifying Properties*

The spectroturbidimetric procedure of Pearce and Kinsella with the modifications by Liceaga-Gesualdo and Li-Chan was used to determine the emulsifying activity index (EAI) and the emulsion stability index (ESI) [38,54]. Briefly, samples (hydrolysates and insect meals) were dispersed at 3.0%, 1.0% and 0.5% (*w*/*v*) in 100 mL McIlvaine buffer (pH 4.0, 5.5 and 7.0) and stored at 4 ◦C for 12 h. Then, sample dispersions were mixed with 25 mL of canola oil using an Ultra-Turrax at 13,500 rpm for 1 min and diluted into tubes containing 0.3% SDS solution to reach an absorbance greater than 0.1. Homogeneity of dilution was ensured by inverting the tube six times. Absorbance

was read at 500 nm with a UV-visible spectrometer. EAI was calculated from the Equation (6) used by Hall et al. [3]:

$$\text{EAI} = \frac{\text{2} \cdot \text{T} \cdot \text{A} \cdot df}{\text{Z} \cdot \text{c} \cdot 100} \tag{6}$$

where *T* is the turbidity, *A* is the absorbance measured, *df* is the dilution factor, *L* is the light path (in meters), ∅ is the volume of the oil phase (0.25) and *c* is the concentration of the aqueous phase. The turbidity was calculated according to Pearce and Kinsella [54]. For ESI, the emulsion was read every 30 min for 90 min and was calculated from the equation used 7 by Hall et al. [3]:

$$\text{ESI} = 100 - \left(\frac{\text{EAI}\_0 - \text{EAI}\_l}{\text{EAI}\_0}\right) \times 100\tag{7}$$

where EAI<sup>0</sup> is the initial EAI (time zero) and EAI<sup>t</sup> is the EAI at 30, 60 and 90 min.
