Moisture migration through chocolate-flavored confectionery coatings

The effect of sucrose, lactose, dextrose, cocoa powder, emulsifier, fat type, and storage environment on the water vapor permeability (WVP) of chocolate-flavored coatings was studied. The WVP of fat films decreased with an increase in the solid fat content (SFC). Cocoa powder and lecithin increased the WVP whereas sugar decreased the WVP through the coatings. There was an increase in the WVP with an increase in the absolute value of the relative humidity across coating containing about 12.5% cocoa powder, 33% sucrose, 0.5% lecithin in coconut oil. This increase was due to swelling of the cocoa powder particles that changed the structure of the coatings. Replacing sucrose with dextrose increased the WVP of the coatings. Failure of the coatings as a moisture barrier at sub-zero temperatures resulted from fracture induced by swelling of the cocoa powder.