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Gum arabic (GA) is the most widely used natural emulsifier in food industry. However, due to its high price and unstable market supply, the search for substitutes of gum arabic has attracted the attention of researchers. Recent studies have shown that sugar beet pectin (SBP) has great potential as a natural emulsifier. However, the mechanisms and differences of GA- and SBP-stabilized emulsions are still unclear. In this study, the interfacial behavior of GA and SBP on the oil-water interface was studied and compared through dissipative quartz crystal microbalance and interfacial dilatational rheology. Then, droplet size, zeta-potential and viscosity of the emulsion stabilized by GA and SBP were measured. Meanwhile, the long-term stability of GA- and SBP-stabilized emulsions was evaluated and compared through a LUMiSizer stability analyzer. The study showed that at the same concentration, SBP-stabilized emulsion had significant advantages of a smaller droplet size, a larger viscosity, a thicker and more elastic interfacial layer, and better long-term stability. A comparison of the long-term stability of SBP2.0%- and GA15.0%-stabilized emulsions, evidenced that the elasticity of the interfacial layer plays a crucial role in the long-term stability of emulsions. This research may provide useful information for finding alternatives to GA. [Display omitted] • SBP and GA forms different interfacial layers at oil-in-water interface. • Elasticity of interfacial layer is crucial to long-term stability of emulsion. • SBP may be a good alternative to GA. [ABSTRACT FROM AUTHOR]

In this study, structural characterization and chemical compositions of three pectins from different sources were studied, which showed that compared with apple pectin (AP) and citrus peel pectin (CPP), sugar beet pectin (SBP) has higher protein contents, feruloylated groups, acetyl groups and more hairy regions. Molecular dynamics simulations showed that HG domain was tiled on the oil-water interface, while RG-Ⅰ and RG-Ⅱ domains were adsorbed on the oil-water interface in a folded form, resulting in a thick viscoelastic film. Dissipative quartz crystal microbalance (QCM-D) and dilatational rheology studies showed that under high-concentration and acidic conditions, pectin molecules were adsorbed in multiple layers at the oil-water interface, forming a thicker viscoelastic film, which was crucial for the long-term stability of pectin-stabilized emulsions. [Display omitted] • HG domain was tiled on the oil-water interface. • RG-Ⅰ and RG-Ⅱ domains adsorbed on the oil-water interface in a folded form. • Pectin molecules adsorbed in multiple layers under acidic conditions. [ABSTRACT FROM AUTHOR]

Previous studies have shown that Mesona chinensis Benth polysaccharide (MP) has a variety of physiological activities, including anti-inflammation, anti-oxidation, immune regulation, etc. In addition, MP can also enhance the gel properties of starch. However, there are few reports about the interfacial properties and long-term emulsion stability of MP. In this study, we measured adsorption kinetics of MP molecules on the oil-water interface, interfacial viscoelasticity and adsorption mass, interfacial film thickness, the resistance of the interfacial film to external perturbations, and droplet size, zeta-potential, viscosity and long-term stability of MP-stabilized emulsion under different pH values. The results represented that MP could form much thicker and more elastic interfacial films on the oil-water interface under pH7 and pH9 conditions than that under pH5 condition. Besides, this interfacial film has stronger resistance to external perturbations, which is very significant for the long-term emulsion stability. This study explores the stability mechanism and application of MP in emulsion, which has a positive effect on expanding the application scene and scope of MP. [Display omitted] • Highly elastic interfacial films have greater resistance to external perturbations. • PH influences the stability and rheological behavior of MP-stabilized emulsion. • Elasticity of interfacial layer is crucial to long-term stability of emulsion. • MP-stabilized emulsion at pH7 and pH9 has better stability than that at pH5. [ABSTRACT FROM AUTHOR]

Emulsions are multiscale and thermodynamically unstable systems which will undergo various unstable processes over time. The behavior of emulsifier molecules at the oil-water interface and the properties of the interfacial film are very important to the stability of the emulsion. In this paper, we mainly discussed the instability phenomena and mechanisms of emulsions, the effects of interfacial films on the long-term stability of emulsions and summarized a set of systematic multiscale combined methods for studying emulsion stability, including droplet size and distribution, zeta-potential, the continuous phase viscosity, adsorption mass and thickness of the interfacial film, interfacial dilatational rheology, interfacial shear rheology, particle tracking microrheology, visualization technologies of the interfacial film, molecular dynamics simulation and the quantitative evaluation methods of emulsion stability. This review provides the latest research progress and a set of systematic multiscale combined techniques and methods for researchers who are committed to the study of oil-water interface and emulsion stability. In addition, this review has important guiding significances for designing and customizing interfacial films with different properties, so as to obtain emulsion-based delivery systems with varying stability, oil digestibility and bioactive substance utilization. [Display omitted] • A set of systematic techniques and methods for the study of oil-water interface were presented. • Structure-induced self-assembly of emulsifier molecules at the oil-water interface is critical for the long-term stability of emulsions. • Emulsion-based delivery systems with varying stability, oil digestibility and bioactive substance utilization can be obtained based on the design and customization of the interfacial film. [ABSTRACT FROM AUTHOR]