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Appropriate pretreatment of proteins and addition of xanthan gum (XG) has the potential to improve the stability of oil-in-water (O/W) emulsions. However, the factors that regulate the enhancement and the mechanism are still not clear, which restricts the realization of improving the emulsion stability by directional design of its structure. Therefore, the effects of whey protein micro-gel particles (WPMPs) and WPMPs-XG complexes on the stability of O/W emulsion were investigated in this article to provide theoretical support. WPMPs with different structures were prepared by pretreatment (controlled high-speed shear treatment of heat-set WPC gels) at pH 3.5–8.5. The impact of initial WPC structure and XG addition on Turbiscan Indexes, mean droplet size and the peroxide values of O/W emulsions was investigated. The results indicate that WPMPs and XG can respectively inhibit droplet coalescence and gravitational separation to improve the physical stability of WPC-stabilized O/W emulsions. The pretreatment significantly enhanced the oxidative stability of WPC-stabilized O/W emulsions. The addition of XG did not necessarily enhance the oxidative stability of O/W emulsions. Whether the oxidative stability of the O/W emulsion with XG is increased or decreased depends on the interface structure of the protein-XG complex. This study has significant implications for the development of novel structures containing lipid phases that are susceptible to oxidation. [ABSTRACT FROM AUTHOR]

Emulsion micro-gels exhibit significant potential as functional ingredients for modifying food texture, replacing saturated fats, or serving as templates for the controlled release of bioactive compounds. Structural design principles are being applied more frequently to develop innovative emulsion micro-gels. In this paper, whey protein concentrate (WPC), κ-carrageenan and sodium alginate (SA) were utilized for preparing emulsion micro-gels. To reveal the regulation mechanism of the structural and physicochemical properties of emulsion micro-gels on lipid digestion, the influence of SA additions on the structural, physicochemical properties and in vitro digestion behavior of κ-carrageenan/WPC-based emulsion micro-gel were explored. The FTIR results suggest that the emulsion micro-gels are formed through non-covalent interactions. With the increase of SA addition (from 0.7 g/100 mL to 1.0 g/100 mL), the decreased mean droplet size, the increased hardness, elasticity indexes, and water holding capacity, the reduced the related peak times all indicated that the emulsion micro-gels exhibit enhanced rheological, stability, and mechanical properties. It can be concluded from the microstructure, particle size distribution of the emulsion micro-gels during simulated digestion and free fatty acid release that both κ -carrageenan/WPC-based emulsion micro-gel and κ -carrageenan/WPC/SA-based emulsion micro-gel can inhibit lipid digestion due to the ability to maintain structural stability and hindering the penetration of bile salts and lipase through the hydrogel networks. And the ability is regulated by the binding properties the gel matrix and oil droplets, which determine the structure and physicochemical properties of emulsion micro-gels. The research suggested that the structure of emulsion micro-gels can be modified to produce various lipid digestion profiles. It may be significant for certain practical application in the design of low-fat food and controlled release of bioactive agents. [ABSTRACT FROM AUTHOR]

The aim of this research was to prepare curdlan-based emulsion micro-gel particles with different concentration of the curdlan (0.5 g/100 mL, 1.0 g/100 mL, 1.5 g/100 mL, 2.0 g/100 mL, 2.5 g/100 mL), which respectively named as CEM(0.5), CEM(1.0), CEM(1.5), CEM(2.0), CEM(2.5). And the microstructural, rheological and texture properties of the emulsion micro-gel particles were investigated. Then, CEM(1.0) was used as a compound fat replacement in pork sausages and the effects of different replacement rates on the caloric value, texture and sensory quality of pork sausages were investigated. The results showed that the WPI and curdlan aggregation, the hardness, shear stress, the G ′ and G ″ moduli of the curdlan-based emulsion micro-gel particles significantly increased with increasing curdlan concentration. CEM(1.0) has the closest sensory quality to pork back fat and uniform inner structure. Digestion behaviors of CEM(1.0) showed that the curdlan gel network can not only delay the lipid digestion, but also inhibit the lipid digestion. The results showed that curdlan-based emulsion micro-gel particles can be used to replace 40% fat to produce low-fat pork sausages which had similar sensory acceptance with full-fat samples. • The curdlan-based emulsion micro-gel particles (CEM) prepared by heat-shearing. • The influence of the curdlan concentration on the CEM was investigated. • CEM(1.0) could be selected as a replacement of pork back fat. • The curdlan gel network can delay and inhibit the lipid digestion. • CEM(1.0) can be used to replace 40% fat to produce low-fat pork sausages. [ABSTRACT FROM AUTHOR]