Search

Using non-amphiphilic polysaccharide to stabilize oil-in-water emulsions is still a challenge in food industry. Polysaccharide microgels showed emulsifying capacity, however, the stability of the formed emulsions is far from the requirements of the food industry. In this work, agarose microgel/Tween-20 suspensions were prepared and further employed in oil-in-water emulsion stabilization. Focuses were taken on the impact of Tween-20 on the emulsifying properties of agarose microgels. Results suggested that Tween-20 could complex with agarose microgels, and microamounts of Tween-20 (0.02 wt%) could apparently improve the emulsifying performance of microgels. Dynamic interfacial pressure and interfacial adsorption of microgels indicated that appropriate amount of Tween-20 (≤0.04 wt%) could benefit the interfacial adsorption of agarose microgels, while excessive Tween-20 (≥0.08 wt%) could compete with agarose microgels for adsorption sites on oil/water interface. Results of this work supporting that surfactant complexing could be a promising solution to prepare polysaccharides based Mickering emulsions. [ABSTRACT FROM AUTHOR]

This work was focused on the fabrication of a stable O/W Pickering emulsion by using cellulose-rich composites that prepared by selectively oxidation with sodium periodate firstly, and followed by grafting dodecylamine to the 2,3-dialdehyde cellulose particles. The structure and properties of the modified cellulose microparticles were characterized, and the performance for the stabilization of O/W Pickering emulsions was investigated. The surface wettability, rheological behavior of the cellulose microparticles before and after being modified had been compared. The results indicated that the hydrophobically modified cellulose microparticles were more effective in emulsifying oil than that of the pristine cellulose microparticles. The contents of oil and cellulose microparticles used had an influence on the size of emulsion droplets, however, the responsiveness of the emulsions towards pH changed slightly, and oil was not leaked from the droplets at decreased pH. This could be explained by the amphiphilicity of the hydrophobically modified cellulose particles. This work provided a facile method for the modification of cellulose microparticles with amphiphilic properties and enhanced emulsifying capacity. The cellulose based particles with biocompatible and environmentally friendly characteristics would be attractive for the applications in biomedicine, pharmaceuticals, cosmetics, etc. [ABSTRACT FROM AUTHOR]

Physical instability and oxidation were two of the most evident problems existing in food emulsions. In this research, a facile approach of solidifying the oil phase by stearic acid was adopted to overcome the above problems simultaneously, emphasising the effect of the oleogelation extent. Polarizing microscope, rheological analysis, and X-ray diffraction (XRD) were used to characterize the oleogelation of the oil phase, and droplet size, microscopic observation and peroxide value analysis were applied to evaluate the emulsion stability. Results showed that with moderate solidification of the oil phase (0.8%–1.0% w/v stearic acid in oil phase), the emulsions exhibited excellent physical stability under the stress of centrifugal force, high salt, and long-term storage. Moreover, the oxidative stability of the emulsions was improved simultaneously, that the increasing of peroxide value was slowed significantly. Excessive solidification (e. g. 3% w/v stearic acid) of the oil phase would weaken these advantages or even bring about opposite results, due to the destruction of the emulsion droplets by the excessive crystallization. Our results suggested that moderate solidification of oil phase would be a feasible and effective approach to improve the stability of o/w emulsions, which would be significant for the industrial-scaled production. • Stearic acid could be used to prepare the starch stabilized oleogel emulsions. • Oleogelation of the oil phase could improve the physical stability of the emulsions. • Lipid oxidation could be inhibited in the oleogel based emulsions. • The emulsion stability was related to the solidification extent of the oil phase. [ABSTRACT FROM AUTHOR]

• The food-grade W/O emulsions based on oleogels had no surfactant. • Beeswax played a decisive role in stabilizing the W/O emulsions. • The W/O emulsions exhibited high stability during 60 d storage. • The W/O emulsions performed excellent thermo-reversible and thixotropic properties. • The W/O emulsions would have promising potential as fat mimetics. Fabrication of food-grade water-in-oil (W/O) emulsions without surfactant, as the primary substitutes of trans -fat and saturated fat, was still a significant challenge in food science. A facial method has been adopted to fabricate W/O emulsions at 20 °C. The obtained emulsion had long-time stability, and there was no apparent phase separation or oiling-out after 60 days of storage. In this system, beeswax served as a stabilizer for both oleogels and oleogel-based emulsions. The sol–gel melting temperature of the oleogel was 37 ± 0.5 °C by regulating beeswax content to 4% w/w, and then the oleogel was used to fabricate W/O emulsion with the droplet diameter of around 9 μm. Thermo-reversible and thixotropic properties of oleogels were both retained for emulsions. Furthermore, both oleogels and oleogel-based emulsions had compact gel-like structures. The self-emulsifying W/O emulsions without surfactant would have great potential applications in food industry, pharmaceutical industry and feed industry. [ABSTRACT FROM AUTHOR]

[Display omitted] • A simple method to observe the oxygen diffusion in the emulsion system was developed. • The oxygen diffusion was strongly related to the lipid oxidation in emulsion. • The emulsion droplet surface could affect the oxygen diffusion and lipid oxidation. • The oil phase and water phase could affect the oxygen diffusion and lipid oxidation. Oxygen diffusion played an important role in the lipid oxidation of food emulsions. In this study, a simple method was developed to quantitatively observe the oxygen diffusion in the oil–water biphasic system, and it was further applied to investigate the relationship between the oxygen diffusion and lipid oxidation in O/W emulsions. Various factors that related to the emulsion oxidation were considered, from their influence on the oxygen diffusion and lipid oxidation in the emulsions. Results showed that there was obvious correlation between the oxygen diffusion and lipid oxidation in O/W emulsions, which reveals the inhibition of oxygen diffusion could apparently slow down the lipid oxidation. Moreover, the changes of oil phase, water phase and interfacial layer of the emulsions, which were related to the oxygen diffusion, could improve the oxidative stability of the emulsions effectively. Our findings are helpful for deep understanding the mechanisms of the lipid oxidation in food emulsions. [ABSTRACT FROM AUTHOR]

It has been a great challenge of using natural polysaccharides to stabilize food emulsions, due to their poor amphiphilicity. In this study, a novel strategy of using polysaccharide to stabilize O/W emulsions was developed, through in situ crosslinking of sodium alginate on oil-water interface. During the emulsifying process, the acetic acid migrated across the interface, and induced the released of calcium ions, which immediately crosslinked the sodium alginate on interface. Results showed that the oil droplets were encapsulated in the integral polysaccharide shells. The droplet size of the emulsions located in the range from 20 to 200 μm. The concentration of sodium alginate and HAc, as well as the mixing rates were showed to be positively related with the thickness of the shell. However, excess calcium ions would disintegrate the shell structure. Additionally, the interfacial crosslinked sodium alginate stabilized emulsions exhibited excellent physical stability under centrifugating and freeze-thawing. [Display omitted] • Emulsions based on in situ crosslinking of alginate were manufactured. • Oil droplets were encapsulated in the integral polysaccharide shells. • Influence of different factors on shell thickness of oil droplets was evaluated. • In situ crosslinking of alginate endow emulsions with excellent physical stability. [ABSTRACT FROM AUTHOR]