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Preparation procedures - Ingredients - Emulsions and composites

4 important questions on Preparation procedures - Ingredients - Emulsions and composites

What is the difference of using lipids or emulsions as barrier?

Lipids may be difficult to apply and have poor mechanical properties when applied in isolation. When incorporated in emulsions, this is less.

How are emulsions applied as a barrier?

The emulsions are sprayed on the product. The solvent (usually water) has to be evaporated and multiple coating steps may be necessary to obtain a film that is sufficiently defect-free.

Why are the drying conditions highly important for emulsion casting techniques?

Drying at high temperatures may lead to creaming and coalescence of the fat globules, forming a homogeneous layer on top of the coating. This reduces the drying rate substantially, as it prevents the transport of water to the vapour phase. The coating may over-heat locally and defects may be formed, ultimately leading to a non-homogeneous, defective coating.