Saehun Mun, David Julian McClements, Jeonghee Surh
Abstract:
Three types of emulsions (ß-Lg-, ß-Lg-pectin-, and ß-Lg-?-carrageenan-coated emulsions) with controlled electrostatic and/or steric interactions were prepared, and then examined for their freeze-dry stability in the absence or presence of 6% maltodextrin (MD). In the absence of MD, all emulsions were highly unstable to freeze-drying, nevertheless, the ß-Lg-pectin-coated emulsions (d 32 =5.37, d 43 =35.11 µm) that were stabilized mostly by steric repulsion showed better stability than the other 2 emulsions (no dried power was obtained). The freeze-dry instability of all emulsions was improved with MD addition, particularly in the ß-Lg- (d 43 =1.10 µm) and ß-Lg-?-carrageenan-coated emulsions (d 43 =0.58 µm) that were stabilized by electrostatic repulsive force. In the presence of MD, the ß-Lg-?-carrageenan-coated emulsions showed the highest stability to freeze-drying, which was attributed to the cooperative impact of steric and electrostatic repulsion. This study implicates that the major mechanism for stabilizing emulsions against freeze-drying could be different depending on the absence or presence of MD.
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Keywords
emulsion, maltodextrin, freeze-dry stability, electrostatic, steric
