Abstract
The ability of emulsifiers (gum arabic, starch and soy protein isolate (SPI)) and texture modifiers (gum tragacanth and carrageenan) alone and as a mixture with SPI to stabilize oil-in-water emulsions at high oil concentrations was studied. Parameters investigated included droplet size distribution, color (DE), viscosity and creaming stability. At 10% (w/v) emulsifier to oil ratio, emulsions stabilized with gum arabic, starch and SPI had average oil droplet sizes lower than 1µm. Increasing the oil content by two-fold (emulsifier/oil ratio of 10:20), increased the average droplet size of the gum arabic and SPI emulsions to 1.5 and 4.2 mm, respectively, while that of the starch emulsion remained unchanged. At 5% oil concentration, gum tragacanth and carrageenan stabilized emulsions yielded two average droplet sizes of 0.5 µm (52.7%) and 1.8 µm (46.5%), and 0.5 µm (48.8%) and 1.7 µm (46.6%), respectively. Increasing the oil concentration to 10% increased the particle size with fairly similar proportions. Gum arabic stabilized emulsions had lower DE than starch and SPI (except at 20% oil content). DE of carrageenan and tragacanth emulsion decreased significantly when used as a mixture with SPI. Droplet size strongly affected color. All concentrated emulsions exhibited shear-thinning behavior irrespective of oil, emulsifier type and concentration. SPI, followed by starch and gum arabic emulsions showed good stabilities over the 15 days storage period. Gum tragacanth and carrageenan emulsion stabilities were only improved when combined with SPI, particularly at 5% oil concentration.
Highlights
Emulsions form the basis of a wide variety of natural and manufactured materials used in the food, pharmaceutical and cosmetic industries (Becher 1985 and 1988; Schramm, 1992; Lin and Mei, 2000; McClements, 2005)
Emulsion concentrates stabilized with gum arabic and soy protein isolate (SPI) both showed an average droplet size of 0.7 m
The average oil droplet size for the starch-stabilized emulsion was smaller (0.4 m and 0.45 m at 10 and 20% oil concentrations, respectively). These results suggest that starch was more effective at producing small droplets during homogenization than gum arabic and SPI at both oil concentrations
Summary
Emulsions form the basis of a wide variety of natural and manufactured materials used in the food, pharmaceutical and cosmetic industries (Becher 1985 and 1988; Schramm, 1992; Lin and Mei, 2000; McClements, 2005). Existing and new ingredients are regularly incorporated into food systems to improve their rheological, physicochemical and nutritional properties. One of the major concerns for emulsions is keeping the emulsion droplets uniformly distributed during storage and consumption (Chanamai and McClements, 2002). This has led the food industry and many researchers to investigate the ability of hydrocolloids and proteins to stabilize emulsion droplets against creaming, flocculation and coalescence, depending on their intended application. The emulsion must have a significant degree of stability in both the concentrated and diluted forms (Tan, 1990)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
