2nd Edition of Agriculture, Forestry, and Horticulture World Conference 2026

Abstract

Abstract: 
Pickering emulsions (PEs) stabilized by protein-polysaccharide complexes have emerged as highly promising alternatives to conventionally stabilized emulsions. Their particle-laden interfaces and percolated network microstructures enable effective fat mimicry, making them ideal candidates for clean-label fat replacement in structured foods. In this study, whey protein isolate (WPI)-pectin microgels were fabricated via heat-induced complex coacervation, followed by high-shear homogenization to yield sub-micron interfacial particles. These microgels were subsequently employed as Pickering stabilizers to formulate oil-in-water (O/W) emulsions, which were then incorporated into mango mousse systems as fat replacers. The primary objective was to systematically evaluate the influence of pectin type (citrus pectin [CP], apple pectin [AP]) and concentration (0.5-1.0% w/w, relative to total emulsion) on PEs microstructure, emulsion property, physical stability, and the resulting mousse’s visual appearance, texture, microstructure and color attribute.
Compared with CP, AP had a higher molecular weight, a greater degree of esterification and a more pronounced abundance of “hairy” regions. Zeta potential analysis confirmed that pectin incorporation significantly increased the net negative surface charge of WPI aggregates. The particle size decreased after pectin addition, indicating that pectin inhibited aggregation of protein particles. The intermoleular electrostatic repulsion plays a critical role in it. FTIR showed that predominant interactions between WPI and pectin were hydrogen bonding. The inclusion of pectin at all concentration reduced the content of α-helix and increased β-sheet and β-turn, indicating partial unfolding and interfacial rigidification. CLSM visualized that pectin decreased the oil droplet sizes, and the emulsion droplets became more concentrated and smaller in size as the concentration of pectin increases. In AP emulsion, the droplets maintained smaller and more homogeneous size compared to CP emulsion at the same concentration. Furthermore, the PEs with pectin, especially AP, showed higher emulsifying activity index, better long-term storage stability, salt ion stability compared to pure WPI-PEs.  
To evaluate application potential, Pickering emulsions with 1.0% pectin were used as fat replacer in mango mousse with different fat replacement rates (20%, 40%, and 60%, w/w). The results showed that the mousse with AP-PEs effectively mimicked structural integrity of full-fat counterparts, and had significantly better appearance and texture compared to skim mousse. AP-PEs mousse with 60% replacement rate has the most similar texture to full-fat mousse in terms of hardness, gumminess, and chewiness compared to pure WPI- and CP-PEs. 
These findings collectively indicated that pectin (particularly apple pectin) interacted predominantly with WPI via hydrogen-bonding, leading to its adsorption onto the surface of heat-induced WPI microgels. This interfacial assembly facilitated the formation of dense network structure that encapsulated oil droplets, thereby reinforcing the interfacial film and significantly enhancing both emulsifying efficiency and physical stability. Furthermore, Pickering emulsions formulated with 1.0% AP and incorporated into mousse at a 60% fat-replacement level used as fat replacers yielded products with more similar appearance and texture to full-fat mousse. Therefore, Pickering emulsion system with WPI-protein microgel is an excellent candidate for fat replacers in mousse production and shows great potential application in reduced-fat foods.