Influence of Maltodextrin Addition on the Freeze-dry Stability of β-Lactoglobulin-based Emulsions with Controlled Electrostatic and/or Steric Interactions

초록

Three types of emulsions (beta-Lg-, beta-Lg-pectin-, and beta-Lg-iota-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 beta-Lg-pectin-coated emulsions (d(32)=5.37, d(43)=35.11 mu m) 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 beta-Lg- (d(43)=1.10 mu m) and beta-Lg-iota-carrageenan-coated emulsions (d(43)=0.58 mu m) that were stabilized by electrostatic repulsive force. In the presence of MD, the beta-Lg-iota-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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