**6. Food Applications**

*6.1. Bioactive Encapsulation and Delivery*

Recently the interest in the fabrication of novel bioactive delivery systems increased continuously [70]. In food applications, various emulsion-based delivery systems are used but they still required long-time physical stability in various environmental conditions because the breakdown of emulsion significantly alter the texture, color, flavor, and shelf life of the products. Xu, Wang [56] found that the curcumin oral bioavailability of the casein– soy soluble polysaccharide complex stabilized emulsions was 11-fold higher compared with curcumin/Tween 20 suspension. Wang et al. [71] found that the addition of soy polysaccharides (soy hull polysaccharide and soy soluble polysaccharide) is capable to decrease the influence of simulated gastric fluid (i.e., pepsin, ionic strength, and pH) on the stability of emulsions.

In recent years, a few novel emulsions such as Pickering emulsions [60], emulsion gels [72], oleogel emulsions [68], high internal phase emulsions, multiple emulsions [69,73], nanoemulsions, and microemulsions [74] have been fabricated for encapsulation and delivery of bioactive compounds (Figure 8). Physically stabilized Pickering emulsions with solid particles that were moderately wetted by oil and water showed improved stability against steric mechanism-based flocculation and coalescence [59]. Soy-based emulsifiers are considered promising Pickering stabilizers due to easy availability, the ability to form nano-aggregates, and health effects. Liu and Tang [75] reported the heat-treated soy glycinin stabilized gel-like Pickering emulsions capable of sustained release β-carotene which was confirmed by the in vitro experiment for intestinal digestion which indicated that the formation of a gel-like network significantly slowed down the release of β-carotene. Muñoz-González et al. [76] produced four emulsion gels containing soy protein, olive oil, and alginate-based cold gelling agen<sup>t</sup> to encapsulate polyphenol. The emulsion gels with added polyphenols exhibited the presence of gallic acid, flavanol monomers, and their derivatives, which play a vital role to make it a suitable system for the delivery of various bioactive compounds. Zhuang, Gaudino [68] fabricated novel soy-lecithin based W/O oleogel emulsions for improved lipid stability and probiotic viability. The oleogel emulsion was composed of 20 wt% oleogelators (soy lecithin: stearic acid, 1:1), 70% canola oil, and 10% water. Flores-Andrade, Allende-Baltazar [61] compared the O/W paprika oleoresin nanoemulsions which were stabilized by whey protein concentrates, soy lecithin, and gum arabic under high-pressure homogenization, and found that soy lecithin was the most effective emulsifier for nanoemulsion preparation.

**Figure 8.** Structures of Pickering emulsions (**a**), emulsion gels (**b**), oleogel emulsions (**c**), high internal phase emulsions (**d**), multiple emulsions (**e**), and nanoemulsions (**f**).
