## 3 Results and Discussion
### Core-in-Wall Emulsions (CIWEs)
At a given set of homogenization conditions and a non-limiting availability of surface active material (protein), an increase in d\({}_{3,2}\) with lipid load can be attributed to an overall longer particle disruption time inside the homogenization valve, a longer period of time that is needed to complete the adsorption of proteins at the newly formed O/W interface and to a very significant decrease in the particles encountering time, that is, the time that is needed for two or more partially protein-coated oil droplets to encounter each other and form a cluster [55; 56]. Results (Table 1) indicated that in most cases, d\({}_{3,2}\) of CIWE slightly, yet significantly, increased (\(p<0.05\)) with the proportion of WHPI in the WS. Although not quantified in this study, CIWEs exhibited an increase in viscosity with the concentration of WHPI, especially in CIWEs with high oil content. It has to be noticed that the viscosity of CIWEs 7.5/12.5/25:75 and 10.0/10.0/25:75 was too high to allow for atomization and spray drying. The effects of the concentration of WHPI on d\({}_{3,2}\) could thus probably be attributed to the inverse relationships between viscosity and homogenization efficiency [55]. Results (Figure 1 and Table 1) are in agreements with earlier reports about the formation and PSD properties of CIWEs with WS consisting of proteins and carbohydrates [30; 31; 43; 44]. In agreement with such earlier reports, results of this study have indicated that the utilization of a low-molecular-weight carbohydrate, lactose, allowed for preparing CIWEs with a PSD that exhibited only a very minimal manifestation of bimodality. Unlike what has been reported for CIWEs containing proteins and a low-DE-value maltodext [30], the inclusion of lactose in the WS did not adversely affect the formation of CIWEs with desired PSD properties. Figure 1: Representative particles size distribution (PSD) of core-in-wall-emulsions (CIWEs). The adsorption of proteins at the O/W interface and the properties of the resulting interfacially-adsorbed films is of great importance to the colloidal properties, stability, and functionality of protein-stabilized CIWEs. The composition, physico-chemical-, rheological-, and structural-properties of these films also affect, to a varying degree, the oxidative stability and core-release characteristics of the microcapsules that are prepared with these CIWEs [42; 54]. Results (Table 2) indicated that the surface excess (\(\Gamma\)) of the CIWEs ranged from 1.597 to 5.316 mg/m\({}^{2}\) and was influenced by the combined effects of the composition and PSD properties of the CIWE (\(p<0.05\)). In most cases, for a given W:C ratio, \(\Gamma\) increased with the proportion of WHPI that was included in the CIWE (\(p<0.05\)), however, at a W:C ratio of 50:50 and 25:75, similar \(\Gamma\) was obtained with wall systems 7.5/12.0 and 10.0/10.0 (\(p>0.05\)). In all cases, for a given wall composition, \(\Gamma\) was inversely related to the core content of the CIWE (\(p<0.05\)) and it thus reflected the overall increase in the interfacial area with core load. The extent to which \(\Gamma\) decreased with the increase in core content was influenced by wall composition. For example, \(\Gamma\) in CIWE 2.5/17.5/25:75 and 10.0/10.0/25:75 was 42 and 27% lower than that in CIWE 2.5/17.7/75:25 and 10.0/10.0/75:25, respectively. However, \(\Gamma\) in CIWEs 5.0/15.0/25:75 and 7.5/12.5/25:75 was 14 and 9% lower than that in CIWEs 5.0/15.0/75:25 and 7.5/12.5/75:25, respectively. Overall, the results were in agreement with what has been reported for CIWEs with wall systems consisting of WHPI and maltodext [30]. As explained in Section 2.3, and in agreement with what has been previously reported [30], the results reflected the presence of only protein molecules that were truly engaged at the O/W interface.