Abstract
Confectionery coating fat (CCF ) emulsions (40 wt.%) were prepared by mixing liquid fat with solutions (1-4 wt.%) of selected polymeric and small molecule surfactants, and homogenizing to a mean particle diameter of 0.71±0.05 μm. Aliquots of the emulsions were temperature cycled (40 to -10 to 40°C at 1.5°C min-1) four times in a differential scanning calorimeter. The stable emulsion droplets crystallized at 0-6°C (depending on the type of emulsifier) while the non-emulsified fat crystallized at ∼15°C. The ratio of the enthalpies at these temperatures was used to calculate the proportion of the emulsion that had destabilized after each thermal cycle. All of the small molecule-stabilized emulsions largely destabilized after one cycle. The caseinate-stabilized emulsions were relatively resistant to several thermal cycles unless ethanol (30 wt.%) was added or the pH lowered to 5, in both cases they destabilized during the first cycle. When a small molecule surfactant was added to displace the caseinate from the interface, there was a sharp reduction in stability at the surfactant to protein molar ratio R>25. Whey protein-stabilized emulsions were partly unstable to freeze-thaw even following a thermal pretreatment to denature the proteins. Cryo-SEM confirmed the destabilization of the emulsions was due to partial coalescence.
Original language | English (US) |
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Pages (from-to) | 251-262 |
Number of pages | 12 |
Journal | Colloids and Surfaces A: Physicochemical and Engineering Aspects |
Volume | 223 |
Issue number | 1-3 |
DOIs | |
State | Published - Aug 21 2003 |
All Science Journal Classification (ASJC) codes
- Surfaces and Interfaces
- Physical and Theoretical Chemistry
- Colloid and Surface Chemistry