Talbot, G., Smith, K., Favre, L., ‘t Zand, I., Tackling migration, Food Ingredients, Feb 2008, 22-24
Migration of oils from soft filling fat phases into outer chocolate coatings has long been a problem for the confectionery industry. Such migration causes a softening of the chocolate and a hardening of the filling, thus losing much of the textural difference found in the original, fresh product. To a large extent, such effects are understandable. It is the liquid phase of the filling which moves out of the filling so what is left must be more solid and, hence, harder. As it is also the liquid phase of the filling which moves into the chocolate, the chocolate must become richer in liquid and, hence, softer. It’s obvious, really! What is not quite so obvious is that such oil migration is often accompanied by the formation of fat bloom on the chocolate surface. Why should migration of oils from a filling into chocolate accelerate the formation of fat bloom?