Refractive Index of the Dispersed Phase in Oil-in-Water Emulsions: Its Dependence on Droplet Size and Aging

Authors

  • APURBA K. RAY,

    1. Authors Ray, Johnson, and Sullivan are affiliated with Corporate Research & Development Dept. The Coca-Cola Company, Atlanta, GA 30301.
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  • JOHN K. JOHNSON,

    1. Authors Ray, Johnson, and Sullivan are affiliated with Corporate Research & Development Dept. The Coca-Cola Company, Atlanta, GA 30301.
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  • ROBERT J. SULLIVAN

    1. Authors Ray, Johnson, and Sullivan are affiliated with Corporate Research & Development Dept. The Coca-Cola Company, Atlanta, GA 30301.
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  • Thanks are due to Mr. James Cyrus for experimental assistance and to Dr. George Miller of Georgia Institute of Technology, Atlanta, for his help in the refractive index measurements.

ABSTRACT

A simple method of determining the refractive index of the dispersed phase was applied on different gum-stabilized oil-in-water emulsions, in which this refractive index is taken to be equal to that of the continuous phase at (extrapolated) zero optical density point. Refractive indices of dispersed phases were usually lower than those of the oil part alone. In dilute emulsions, the refractive index of the dispersed phase increased with time, while optical density of emulsion decreased. In aged concentrated emulsions, both refractive index and optical density decreased with time. At a given composition, the refractive index and optical density varied directly with droplet size. The results are interpreted in terms of reasonable physical and chemicl phenomena.

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