Lecithin influences cocoa butter crystallization depending on concentration and matrix

The isothermal crystallization at 20°C of cocoa butter (CB) or milk chocolate (MC) with addition of two different sunflower lecithins and one soy lecithin in different concentrations was investigated by differential scanning calorimetry (DSC), oscillatory rheology and a dynamic experiment. A two-step crystallization process was observed with first formation of an unstable alpha polymorph followed by a polymorphic transition to betaâ . In the CB matrix, different measuring techniques led to distinct observations by addition of 1.5% lecithin on fat base. DSC showed a faster alpha crystallization with addition of lecithin, while rheology measurements demonstrated the reverse effect. However, both measuring techniques evidenced a faster polymorphic transition to the betaâ polymorph in lecithin enriched samples. Between the different lecithins no large differences could be detected by the static measuring techniques, while the dynamic experiment exhibited a clearly lower crystallization rate for lecithin B, which was even lower than the pure CB. A remarkable concentration effect was visible in the CB matrix with in general a reduced effect at higher lecithin concentrations. Finally, a different behavior was observed in the MC matrix compared to the CB matrix, presumably by the interaction of lecithin with sugar.